whisperv5: integrate whisper and add whisper RPC simulator

18 files changed, 1133 insertions, 472 deletions

diff --git a/whisper/whisperv5/api.go b/whisper/whisperv5/api.go
index 1a4e4d879..fd25a4206 100644
--- a/whisper/whisperv5/api.go
+++ b/whisper/whisperv5/api.go
@@ -17,494 +17,575 @@
 package whisperv5
 
 import (
-	"encoding/json"
+	"context"
 	"errors"
 	"fmt"
+	"time"
+	"crypto/ecdsa"
+	"sync"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p/discover"
+	"github.com/ethereum/go-ethereum/rpc"
 )
 
-var whisperOfflineErr = errors.New("whisper is offline")
+const (
+	filterTimeout = 300 // filters are considered timeout out after filterTimeout seconds
+)
+
+var (
+	SymAsymErr             = errors.New("specify either a symetric or a asymmetric key")
+	InvalidSymmetricKeyErr = errors.New("invalid symmetric key")
+	InvalidPublicKeyErr    = errors.New("invalid public key")
+	InvalidSigningPubKey   = errors.New("invalid signing public key")
+	TooLowPoWErr           = errors.New("message rejected, PoW too low")
+	NoTopicsErr            = errors.New("missing topic(s)")
+)
 
-// PublicWhisperAPI provides the whisper RPC service.
+// PublicWhisperAPI provides the whisper RPC service that can be
+// use publicly without security implications.
 type PublicWhisperAPI struct {
-	whisper *Whisper
+	w *Whisper
+
+	mu       sync.Mutex
+	lastUsed map[string]time.Time // keeps track when a filter was polled for the last time.
 }
 
 // NewPublicWhisperAPI create a new RPC whisper service.
 func NewPublicWhisperAPI(w *Whisper) *PublicWhisperAPI {
-	return &PublicWhisperAPI{whisper: w}
+	api := &PublicWhisperAPI{
+		w:        w,
+		lastUsed: make(map[string]time.Time),
+	}
+
+	go api.run()
+	return api
 }
 
-// Start starts the Whisper worker threads.
-func (api *PublicWhisperAPI) Start() error {
-	if api.whisper == nil {
-		return whisperOfflineErr
+// run the api event loop.
+// this loop deletes filter that have not been used within filterTimeout
+func (api *PublicWhisperAPI) run() {
+	timeout := time.NewTicker(2 * time.Minute)
+	for {
+		<-timeout.C
+
+		api.mu.Lock()
+		for id, lastUsed := range api.lastUsed {
+			if time.Since(lastUsed).Seconds() >= filterTimeout {
+				delete(api.lastUsed, id)
+				if err := api.w.Unsubscribe(id); err != nil {
+					log.Error("could not unsubscribe whisper filter", "error", err)
+				}
+				log.Debug("delete whisper filter (timeout)", "id", id)
+			}
+		}
+		api.mu.Unlock()
 	}
-	return api.whisper.Start(nil)
 }
 
-// Stop stops the Whisper worker threads.
-func (api *PublicWhisperAPI) Stop() error {
-	if api.whisper == nil {
-		return whisperOfflineErr
-	}
-	return api.whisper.Stop()
+// Version returns the Whisper sub-protocol version.
+func (api *PublicWhisperAPI) Version(ctx context.Context) string {
+	return ProtocolVersionStr
 }
 
-// Version returns the Whisper version this node offers.
-func (api *PublicWhisperAPI) Version() (hexutil.Uint, error) {
-	if api.whisper == nil {
-		return 0, whisperOfflineErr
-	}
-	return hexutil.Uint(api.whisper.Version()), nil
+// Info contains diagnostic information.
+type Info struct {
+	Memory         int     `json:"memory"`         // Memory size of the floating messages in bytes.
+	Message        int     `json:"message"`        // Number of floating messages.
+	MinPow         float64 `json:"minPow"`         // Minimal accepted PoW
+	MaxMessageSize uint32  `json:"maxMessageSize"` // Maximum accepted message size
 }
 
-// Info returns the Whisper statistics for diagnostics.
-func (api *PublicWhisperAPI) Info() (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
+// Info returns diagnostic information about the whisper node.
+func (api *PublicWhisperAPI) Info(ctx context.Context) Info {
+	stats := api.w.Stats()
+	return Info{
+		Memory:         stats.memoryUsed,
+		Message:        len(api.w.messageQueue) + len(api.w.p2pMsgQueue),
+		MinPow:         api.w.MinPow(),
+		MaxMessageSize: api.w.MaxMessageSize(),
 	}
-	return api.whisper.Stats(), nil
 }
 
-// SetMaxMessageLength sets the maximal message length allowed by this node
-func (api *PublicWhisperAPI) SetMaxMessageLength(val int) error {
-	if api.whisper == nil {
-		return whisperOfflineErr
-	}
-	return api.whisper.SetMaxMessageLength(val)
+// SetMaxMessageSize sets the maximum message size that is accepted.
+// Upper limit is defined in whisperv5.MaxMessageSize.
+func (api *PublicWhisperAPI) SetMaxMessageSize(ctx context.Context, size uint32) (bool, error) {
+	return true, api.w.SetMaxMessageSize(size)
 }
 
-// SetMinimumPoW sets the minimal PoW required by this node
-func (api *PublicWhisperAPI) SetMinimumPoW(val float64) error {
-	if api.whisper == nil {
-		return whisperOfflineErr
-	}
-	return api.whisper.SetMinimumPoW(val)
+// SetMinPow sets the minimum PoW for a message before it is accepted.
+func (api *PublicWhisperAPI) SetMinPoW(ctx context.Context, pow float64) (bool, error) {
+	return true, api.w.SetMinimumPoW(pow)
 }
 
-// AllowP2PMessagesFromPeer marks specific peer trusted, which will allow it
-// to send historic (expired) messages.
-func (api *PublicWhisperAPI) AllowP2PMessagesFromPeer(enode string) error {
-	if api.whisper == nil {
-		return whisperOfflineErr
-	}
+// MarkTrustedPeer marks a peer trusted. , which will allow it to send historic (expired) messages.
+// Note: This function is not adding new nodes, the node needs to exists as a peer.
+func (api *PublicWhisperAPI) MarkTrustedPeer(ctx context.Context, enode string) (bool, error) {
 	n, err := discover.ParseNode(enode)
 	if err != nil {
-		return errors.New("failed to parse enode of trusted peer: " + err.Error())
+		return false, err
 	}
-	return api.whisper.AllowP2PMessagesFromPeer(n.ID[:])
+	return true, api.w.AllowP2PMessagesFromPeer(n.ID[:])
 }
 
-// HasKeyPair checks if the whisper node is configured with the private key
-// of the specified public pair.
-func (api *PublicWhisperAPI) HasKeyPair(id string) (bool, error) {
-	if api.whisper == nil {
-		return false, whisperOfflineErr
-	}
-	return api.whisper.HasKeyPair(id), nil
+// NewKeyPair generates a new public and private key pair for message decryption and encryption.
+// It returns an ID that can be used to refer to the keypair.
+func (api *PublicWhisperAPI) NewKeyPair(ctx context.Context) (string, error) {
+	return api.w.NewKeyPair()
 }
 
-// DeleteKeyPair deletes the specifies key if it exists.
-func (api *PublicWhisperAPI) DeleteKeyPair(id string) (bool, error) {
-	if api.whisper == nil {
-		return false, whisperOfflineErr
+// AddPrivateKey imports the given private key.
+func (api *PublicWhisperAPI) AddPrivateKey(ctx context.Context, privateKey hexutil.Bytes) (string, error) {
+	key, err := crypto.ToECDSA(privateKey)
+	if err != nil {
+		return "", err
 	}
-	return api.whisper.DeleteKeyPair(id), nil
+	return api.w.AddKeyPair(key)
 }
 
-// NewKeyPair generates a new cryptographic identity for the client, and injects
-// it into the known identities for message decryption.
-func (api *PublicWhisperAPI) NewKeyPair() (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
+// DeleteKeyPair removes the key with the given key if it exists.
+func (api *PublicWhisperAPI) DeleteKeyPair(ctx context.Context, key string) (bool, error) {
+	if ok := api.w.DeleteKeyPair(key); ok {
+		return true, nil
 	}
-	return api.whisper.NewKeyPair()
+	return false, fmt.Errorf("key pair %s not found", key)
 }
 
-// GetPublicKey returns the public key for identity id
-func (api *PublicWhisperAPI) GetPublicKey(id string) (hexutil.Bytes, error) {
-	if api.whisper == nil {
-		return nil, whisperOfflineErr
-	}
-	key, err := api.whisper.GetPrivateKey(id)
+// HasKeyPair returns an indication if the node has a key pair that is associated with the given id.
+func (api *PublicWhisperAPI) HasKeyPair(ctx context.Context, id string) bool {
+	return api.w.HasKeyPair(id)
+}
+
+// GetPublicKey returns the public key associated with the given key. The key is the hex
+// encoded representation of a key in the form specified in section 4.3.6 of ANSI X9.62.
+func (api *PublicWhisperAPI) GetPublicKey(ctx context.Context, id string) (hexutil.Bytes, error) {
+	key, err := api.w.GetPrivateKey(id)
 	if err != nil {
-		return nil, err
+		return hexutil.Bytes{}, err
 	}
 	return crypto.FromECDSAPub(&key.PublicKey), nil
 }
 
-// GetPrivateKey returns the private key for identity id
-func (api *PublicWhisperAPI) GetPrivateKey(id string) (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
-	}
-	key, err := api.whisper.GetPrivateKey(id)
+// GetPublicKey returns the private key associated with the given key. The key is the hex
+// encoded representation of a key in the form specified in section 4.3.6 of ANSI X9.62.
+func (api *PublicWhisperAPI) GetPrivateKey(ctx context.Context, id string) (hexutil.Bytes, error) {
+	key, err := api.w.GetPrivateKey(id)
 	if err != nil {
-		return "", err
+		return hexutil.Bytes{}, err
 	}
-	return common.ToHex(crypto.FromECDSA(key)), nil
+	return crypto.FromECDSA(key), nil
 }
 
-// GenerateSymmetricKey generates a random symmetric key and stores it under id,
-// which is then returned. Will be used in the future for session key exchange.
-func (api *PublicWhisperAPI) GenerateSymmetricKey() (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
-	}
-	return api.whisper.GenerateSymKey()
+// NewSymKey generate a random symmetric key.
+// It returns an ID that can be used to refer to the key.
+// Can be used encrypting and decrypting messages where the key is known to both parties.
+func (api *PublicWhisperAPI) NewSymKey(ctx context.Context) (string, error) {
+	return api.w.GenerateSymKey()
 }
 
-// AddSymmetricKeyDirect stores the key, and returns its id.
-func (api *PublicWhisperAPI) AddSymmetricKeyDirect(key hexutil.Bytes) (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
-	}
-	return api.whisper.AddSymKeyDirect(key)
+// AddSymKey import a symmetric key.
+// It returns an ID that can be used to refer to the key.
+// Can be used encrypting and decrypting messages where the key is known to both parties.
+func (api *PublicWhisperAPI) AddSymKey(ctx context.Context, key hexutil.Bytes) (string, error) {
+	return api.w.AddSymKeyDirect([]byte(key))
 }
 
-// AddSymmetricKeyFromPassword generates the key from password, stores it, and returns its id.
-func (api *PublicWhisperAPI) AddSymmetricKeyFromPassword(password string) (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
-	}
-	return api.whisper.AddSymKeyFromPassword(password)
+// GenerateSymKeyFromPassword derive a key from the given password, stores it, and returns its ID.
+func (api *PublicWhisperAPI) GenerateSymKeyFromPassword(ctx context.Context, passwd string) (string, error) {
+	return api.w.AddSymKeyFromPassword(passwd)
 }
 
-// HasSymmetricKey returns true if there is a key associated with the given id.
-// Otherwise returns false.
-func (api *PublicWhisperAPI) HasSymmetricKey(id string) (bool, error) {
-	if api.whisper == nil {
-		return false, whisperOfflineErr
-	}
-	res := api.whisper.HasSymKey(id)
-	return res, nil
+// HasSymKey returns an indication if the node has a symmetric key associated with the given key.
+func (api *PublicWhisperAPI) HasSymKey(ctx context.Context, id string) bool {
+	return api.w.HasSymKey(id)
 }
 
-// GetSymmetricKey returns the symmetric key associated with the given id.
-func (api *PublicWhisperAPI) GetSymmetricKey(name string) (hexutil.Bytes, error) {
-	if api.whisper == nil {
-		return nil, whisperOfflineErr
-	}
-	b, err := api.whisper.GetSymKey(name)
-	if err != nil {
-		return nil, err
-	}
-	return b, nil
+// GetSymKey returns the symmetric key associated with the given id.
+func (api *PublicWhisperAPI) GetSymKey(ctx context.Context, id string) (hexutil.Bytes, error) {
+	return api.w.GetSymKey(id)
 }
 
-// DeleteSymmetricKey deletes the key associated with the name string if it exists.
-func (api *PublicWhisperAPI) DeleteSymmetricKey(name string) (bool, error) {
-	if api.whisper == nil {
-		return false, whisperOfflineErr
-	}
-	res := api.whisper.DeleteSymKey(name)
-	return res, nil
+// DeleteSymKey deletes the symmetric key that is associated with the given id.
+func (api *PublicWhisperAPI) DeleteSymKey(ctx context.Context, id string) bool {
+	return api.w.DeleteSymKey(id)
 }
 
-// Subscribe creates and registers a new filter to watch for inbound whisper messages.
-// Returns the ID of the newly created filter.
-func (api *PublicWhisperAPI) Subscribe(args WhisperFilterArgs) (string, error) {
-	if api.whisper == nil {
-		return "", whisperOfflineErr
-	}
+//go:generate gencodec -type NewMessage -field-override newMessageOverride -out gen_newmessage_json.go
+
+// NewMessage represents a new whisper message that is posted through the RPC.
+type NewMessage struct {
+	SymKeyID   string    `json:"symKeyID"`
+	PublicKey  []byte    `json:"pubKey"`
+	Sig        string    `json:"sig"`
+	TTL        uint32    `json:"ttl"`
+	Topic      TopicType `json:"topic"`
+	Payload    []byte    `json:"payload"`
+	Padding    []byte    `json:"padding"`
+	PowTime    uint32    `json:"powTime"`
+	PowTarget  float64   `json:"powTarget"`
+	TargetPeer string    `json:"targetPeer"`
+}
 
-	filter := Filter{
-		PoW:      args.MinPoW,
-		Messages: make(map[common.Hash]*ReceivedMessage),
-		AllowP2P: args.AllowP2P,
-	}
+type newMessageOverride struct {
+	PublicKey hexutil.Bytes
+	Payload   hexutil.Bytes
+	Padding   hexutil.Bytes
+}
 
-	var err error
-	for i, bt := range args.Topics {
-		if len(bt) == 0 || len(bt) > 4 {
-			return "", errors.New(fmt.Sprintf("subscribe: topic %d has wrong size: %d", i, len(bt)))
-		}
-		filter.Topics = append(filter.Topics, bt)
+// Post a message on the Whisper network.
+func (api *PublicWhisperAPI) Post(ctx context.Context, req NewMessage) (bool, error) {
+	var (
+		symKeyGiven = len(req.SymKeyID) > 0
+		pubKeyGiven = len(req.PublicKey) > 0
+		err         error
+	)
+
+	// user must specify either a symmetric or a asymmetric key
+	if (symKeyGiven && pubKeyGiven) || (!symKeyGiven && !pubKeyGiven) {
+		return false, SymAsymErr
 	}
 
-	if err = ValidateKeyID(args.Key); err != nil {
-		return "", errors.New("subscribe: " + err.Error())
+	params := &MessageParams{
+		TTL:      req.TTL,
+		Payload:  req.Payload,
+		Padding:  req.Padding,
+		WorkTime: req.PowTime,
+		PoW:      req.PowTarget,
+		Topic:    req.Topic,
 	}
 
-	if len(args.Sig) > 0 {
-		sb := common.FromHex(args.Sig)
-		if sb == nil {
-			return "", errors.New("subscribe: sig parameter is invalid")
-		}
-		filter.Src = crypto.ToECDSAPub(sb)
-		if !ValidatePublicKey(filter.Src) {
-			return "", errors.New("subscribe: invalid 'sig' field")
+	// Set key that is used to sign the message
+	if len(req.Sig) > 0 {
+		if params.Src, err = api.w.GetPrivateKey(req.Sig); err != nil {
+			return false, err
 		}
 	}
 
-	if args.Symmetric {
-		if len(args.Topics) == 0 {
-			return "", errors.New("subscribe: at least one topic must be specified with symmetric encryption")
+	// Set symmetric key that is used to encrypt the message
+	if symKeyGiven {
+		if params.Topic == (TopicType{}) { // topics are mandatory with symmetric encryption
+			return false, NoTopicsErr
 		}
-		symKey, err := api.whisper.GetSymKey(args.Key)
-		if err != nil {
-			return "", errors.New("subscribe: invalid key ID")
+		if params.KeySym, err = api.w.GetSymKey(req.SymKeyID); err != nil {
+			return false, err
 		}
-		if !validateSymmetricKey(symKey) {
-			return "", errors.New("subscribe: retrieved key is invalid")
-		}
-		filter.KeySym = symKey
-		filter.SymKeyHash = crypto.Keccak256Hash(filter.KeySym)
-	} else {
-		filter.KeyAsym, err = api.whisper.GetPrivateKey(args.Key)
-		if err != nil {
-			return "", errors.New("subscribe: invalid key ID")
+		if !validateSymmetricKey(params.KeySym) {
+			return false, InvalidSymmetricKeyErr
 		}
-		if filter.KeyAsym == nil {
-			return "", errors.New("subscribe: non-existent identity provided")
+	}
+
+	// Set asymmetric key that is used to encrypt the message
+	if pubKeyGiven {
+		params.Dst = crypto.ToECDSAPub(req.PublicKey)
+		if !ValidatePublicKey(params.Dst) {
+			return false, InvalidPublicKeyErr
 		}
 	}
 
-	return api.whisper.Subscribe(&filter)
-}
+	// encrypt and sent message
+	whisperMsg, err := NewSentMessage(params)
+	if err != nil {
+		return false, err
+	}
 
-// Unsubscribe disables and removes an existing filter.
-func (api *PublicWhisperAPI) Unsubscribe(id string) {
-	api.whisper.Unsubscribe(id)
-}
+	env, err := whisperMsg.Wrap(params)
+	if err != nil {
+		return false, err
+	}
+
+	// send to specific node (skip PoW check)
+	if len(req.TargetPeer) > 0 {
+		n, err := discover.ParseNode(req.TargetPeer)
+		if err != nil {
+			return false, fmt.Errorf("failed to parse target peer: %s", err)
+		}
+		return true, api.w.SendP2PMessage(n.ID[:], env)
+	}
 
-// GetSubscriptionMessages retrieves all the new messages matched by the corresponding
-// subscription filter since the last retrieval.
-func (api *PublicWhisperAPI) GetNewSubscriptionMessages(id string) []*WhisperMessage {
-	f := api.whisper.GetFilter(id)
-	if f != nil {
-		newMail := f.Retrieve()
-		return toWhisperMessages(newMail)
+	// ensure that the message PoW meets the node's minimum accepted PoW
+	if req.PowTarget < api.w.MinPow() {
+		return false, TooLowPoWErr
 	}
-	return toWhisperMessages(nil)
+
+	return true, api.w.Send(env)
 }
 
-// GetMessages retrieves all the floating messages that match a specific subscription filter.
-// It is likely to be called once per session, right after Subscribe call.
-func (api *PublicWhisperAPI) GetFloatingMessages(id string) []*WhisperMessage {
-	all := api.whisper.Messages(id)
-	return toWhisperMessages(all)
+//go:generate gencodec -type Criteria -field-override criteriaOverride -out gen_criteria_json.go
+
+// Criteria holds various filter options for inbound messages.
+type Criteria struct {
+	SymKeyID     string      `json:"symKeyID"`
+	PrivateKeyID string      `json:"privateKeyID"`
+	Sig          []byte      `json:"sig"`
+	MinPow       float64     `json:"minPow"`
+	Topics       []TopicType `json:"topics"`
+	AllowP2P     bool        `json:"allowP2P"`
 }
 
-// toWhisperMessages converts a Whisper message to a RPC whisper message.
-func toWhisperMessages(messages []*ReceivedMessage) []*WhisperMessage {
-	msgs := make([]*WhisperMessage, len(messages))
-	for i, msg := range messages {
-		msgs[i] = NewWhisperMessage(msg)
-	}
-	return msgs
+type criteriaOverride struct {
+	Sig hexutil.Bytes
 }
 
-// Post creates a whisper message and injects it into the network for distribution.
-func (api *PublicWhisperAPI) Post(args PostArgs) error {
-	if api.whisper == nil {
-		return whisperOfflineErr
+// Messages set up a subscription that fires events when messages arrive that match
+// the given set of criteria.
+func (api *PublicWhisperAPI) Messages(ctx context.Context, crit Criteria) (*rpc.Subscription, error) {
+	var (
+		symKeyGiven = len(crit.SymKeyID) > 0
+		pubKeyGiven = len(crit.PrivateKeyID) > 0
+		err         error
+	)
+
+	// ensure that the RPC connection supports subscriptions
+	notifier, supported := rpc.NotifierFromContext(ctx)
+	if !supported {
+		return nil, rpc.ErrNotificationsUnsupported
 	}
 
-	var err error
-	params := MessageParams{
-		TTL:      args.TTL,
-		WorkTime: args.PowTime,
-		PoW:      args.PowTarget,
-		Payload:  args.Payload,
-		Padding:  args.Padding,
+	// user must specify either a symmetric or a asymmetric key
+	if (symKeyGiven && pubKeyGiven) || (!symKeyGiven && !pubKeyGiven) {
+		return nil, SymAsymErr
 	}
 
-	if len(args.Key) == 0 {
-		return errors.New("post: key is missing")
+	filter := Filter{
+		PoW:      crit.MinPow,
+		Messages: make(map[common.Hash]*ReceivedMessage),
+		AllowP2P: crit.AllowP2P,
 	}
 
-	if len(args.Sig) > 0 {
-		params.Src, err = api.whisper.GetPrivateKey(args.Sig)
-		if err != nil {
-			return err
-		}
-		if params.Src == nil {
-			return errors.New("post: empty identity")
+	if len(crit.Sig) > 0 {
+		filter.Src = crypto.ToECDSAPub(crit.Sig)
+		if !ValidatePublicKey(filter.Src) {
+			return nil, InvalidSigningPubKey
 		}
 	}
 
-	if len(args.Topic) == TopicLength {
-		params.Topic = BytesToTopic(args.Topic)
-	} else if len(args.Topic) != 0 {
-		return errors.New(fmt.Sprintf("post: wrong topic size %d", len(args.Topic)))
+	for i, bt := range crit.Topics {
+		if len(bt) == 0 || len(bt) > 4 {
+			return nil, fmt.Errorf("subscribe: topic %d has wrong size: %d", i, len(bt))
+		}
+		filter.Topics = append(filter.Topics, bt[:])
 	}
 
-	if args.Type == "sym" {
-		if err = ValidateKeyID(args.Key); err != nil {
-			return err
+	// listen for message that are encrypted with the given symmetric key
+	if symKeyGiven {
+		if len(filter.Topics) == 0 {
+			return nil, NoTopicsErr
 		}
-		params.KeySym, err = api.whisper.GetSymKey(args.Key)
+		key, err := api.w.GetSymKey(crit.SymKeyID)
 		if err != nil {
-			return err
+			return nil, err
 		}
-		if !validateSymmetricKey(params.KeySym) {
-			return errors.New("post: key for symmetric encryption is invalid")
-		}
-		if len(params.Topic) == 0 {
-			return errors.New("post: topic is missing for symmetric encryption")
+		if !validateSymmetricKey(key) {
+			return nil, InvalidSymmetricKeyErr
 		}
-	} else if args.Type == "asym" {
-		kb := common.FromHex(args.Key)
-		if kb == nil {
-			return errors.New("post: public key for asymmetric encryption is invalid")
-		}
-		params.Dst = crypto.ToECDSAPub(kb)
-		if !ValidatePublicKey(params.Dst) {
-			return errors.New("post: public key for asymmetric encryption is invalid")
-		}
-	} else {
-		return errors.New("post: wrong type (sym/asym)")
+		filter.KeySym = key
+		filter.SymKeyHash = crypto.Keccak256Hash(filter.KeySym)
 	}
 
-	// encrypt and send
-	message, err := NewSentMessage(&params)
-	if err != nil {
-		return err
+	// listen for messages that are encrypted with the given public key
+	if pubKeyGiven {
+		filter.KeyAsym, err = api.w.GetPrivateKey(crit.PrivateKeyID)
+		if err != nil || filter.KeyAsym == nil {
+			return nil, InvalidPublicKeyErr
+		}
 	}
-	envelope, err := message.Wrap(&params)
+
+	id, err := api.w.Subscribe(&filter)
 	if err != nil {
-		return err
-	}
-	if envelope.size() > api.whisper.maxMsgLength {
-		return errors.New("post: message is too big")
+		return nil, err
 	}
 
-	if len(args.TargetPeer) != 0 {
-		n, err := discover.ParseNode(args.TargetPeer)
-		if err != nil {
-			return errors.New("post: failed to parse enode of target peer: " + err.Error())
-		}
-		return api.whisper.SendP2PMessage(n.ID[:], envelope)
-	} else if args.PowTarget < api.whisper.minPoW {
-		return errors.New("post: target PoW is less than minimum PoW, the message can not be sent")
-	}
-
-	return api.whisper.Send(envelope)
-}
-
-type PostArgs struct {
-	Type       string        `json:"type"`       // "sym"/"asym" (symmetric or asymmetric)
-	TTL        uint32        `json:"ttl"`        // time-to-live in seconds
-	Sig        string        `json:"sig"`        // id of the signing key
-	Key        string        `json:"key"`        // key id (in case of sym) or public key (in case of asym)
-	Topic      hexutil.Bytes `json:"topic"`      // topic (4 bytes)
-	Padding    hexutil.Bytes `json:"padding"`    // optional padding bytes
-	Payload    hexutil.Bytes `json:"payload"`    // payload to be encrypted
-	PowTime    uint32        `json:"powTime"`    // maximal time in seconds to be spent on PoW
-	PowTarget  float64       `json:"powTarget"`  // minimal PoW required for this message
-	TargetPeer string        `json:"targetPeer"` // peer id (for p2p message only)
-}
-
-type WhisperFilterArgs struct {
-	Symmetric bool     // encryption type
-	Key       string   // id of the key to be used for decryption
-	Sig       string   // public key of the sender to be verified
-	MinPoW    float64  // minimal PoW requirement
-	Topics    [][]byte // list of topics (up to 4 bytes each) to match
-	AllowP2P  bool     // indicates wheather direct p2p messages are allowed for this filter
-}
-
-// UnmarshalJSON implements the json.Unmarshaler interface, invoked to convert a
-// JSON message blob into a WhisperFilterArgs structure.
-func (args *WhisperFilterArgs) UnmarshalJSON(b []byte) (err error) {
-	// Unmarshal the JSON message and sanity check
-	var obj struct {
-		Type     string        `json:"type"`
-		Key      string        `json:"key"`
-		Sig      string        `json:"sig"`
-		MinPoW   float64       `json:"minPoW"`
-		Topics   []interface{} `json:"topics"`
-		AllowP2P bool          `json:"allowP2P"`
-	}
-	if err := json.Unmarshal(b, &obj); err != nil {
-		return err
-	}
-
-	switch obj.Type {
-	case "sym":
-		args.Symmetric = true
-	case "asym":
-		args.Symmetric = false
-	default:
-		return errors.New("wrong type (sym/asym)")
-	}
-
-	args.Key = obj.Key
-	args.Sig = obj.Sig
-	args.MinPoW = obj.MinPoW
-	args.AllowP2P = obj.AllowP2P
-
-	// Construct the topic array
-	if obj.Topics != nil {
-		topics := make([]string, len(obj.Topics))
-		for i, field := range obj.Topics {
-			switch value := field.(type) {
-			case string:
-				topics[i] = value
-			case nil:
-				return fmt.Errorf("topic[%d] is empty", i)
-			default:
-				return fmt.Errorf("topic[%d] is not a string", i)
-			}
-		}
-		topicsDecoded := make([][]byte, len(topics))
-		for j, s := range topics {
-			x := common.FromHex(s)
-			if x == nil || len(x) > TopicLength {
-				return fmt.Errorf("topic[%d] is invalid", j)
+	// create subscription and start waiting for message events
+	rpcSub := notifier.CreateSubscription()
+	go func() {
+		// for now poll internally, refactor whisper internal for channel support
+		ticker := time.NewTicker(250 * time.Millisecond)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ticker.C:
+				if filter := api.w.GetFilter(id); filter != nil {
+					for _, rpcMessage := range toMessage(filter.Retrieve()) {
+						if err := notifier.Notify(rpcSub.ID, rpcMessage); err != nil {
+							log.Error("Failed to send notification", "err", err)
+						}
+					}
+				}
+			case <-rpcSub.Err():
+				api.w.Unsubscribe(id)
+				return
+			case <-notifier.Closed():
+				api.w.Unsubscribe(id)
+				return
 			}
-			topicsDecoded[j] = x
 		}
-		args.Topics = topicsDecoded
-	}
+	}()
 
-	return nil
+	return rpcSub, nil
 }
 
-// WhisperMessage is the RPC representation of a whisper message.
-type WhisperMessage struct {
-	Topic     string  `json:"topic"`
-	Payload   string  `json:"payload"`
-	Padding   string  `json:"padding"`
-	Src       string  `json:"sig"`
-	Dst       string  `json:"recipientPublicKey"`
-	Timestamp uint32  `json:"timestamp"`
-	TTL       uint32  `json:"ttl"`
-	PoW       float64 `json:"pow"`
-	Hash      string  `json:"hash"`
+//go:generate gencodec -type Message -field-override messageOverride -out gen_message_json.go
+
+// Message is the RPC representation of a whisper message.
+type Message struct {
+	Sig       []byte    `json:"sig,omitempty"`
+	TTL       uint32    `json:"ttl"`
+	Timestamp uint32    `json:"timestamp"`
+	Topic     TopicType `json:"topic"`
+	Payload   []byte    `json:"payload"`
+	Padding   []byte    `json:"padding"`
+	PoW       float64   `json:"pow"`
+	Hash      []byte    `json:"hash"`
+	Dst       []byte    `json:"recipientPublicKey,omitempty"`
 }
 
-// NewWhisperMessage converts an internal message into an API version.
-func NewWhisperMessage(message *ReceivedMessage) *WhisperMessage {
-	msg := WhisperMessage{
-		Payload:   common.ToHex(message.Payload),
-		Padding:   common.ToHex(message.Padding),
+type messageOverride struct {
+	Sig     hexutil.Bytes
+	Payload hexutil.Bytes
+	Padding hexutil.Bytes
+	Hash    hexutil.Bytes
+	Dst     hexutil.Bytes
+}
+
+// ToWhisperMessage converts an internal message into an API version.
+func ToWhisperMessage(message *ReceivedMessage) *Message {
+	msg := Message{
+		Payload:   message.Payload,
+		Padding:   message.Padding,
 		Timestamp: message.Sent,
 		TTL:       message.TTL,
 		PoW:       message.PoW,
-		Hash:      common.ToHex(message.EnvelopeHash.Bytes()),
+		Hash:      message.EnvelopeHash.Bytes(),
+		Topic:     message.Topic,
 	}
 
-	if len(message.Topic) == TopicLength {
-		msg.Topic = common.ToHex(message.Topic[:])
-	}
 	if message.Dst != nil {
 		b := crypto.FromECDSAPub(message.Dst)
 		if b != nil {
-			msg.Dst = common.ToHex(b)
+			msg.Dst = b
 		}
 	}
+
 	if isMessageSigned(message.Raw[0]) {
 		b := crypto.FromECDSAPub(message.SigToPubKey())
 		if b != nil {
-			msg.Src = common.ToHex(b)
+			msg.Sig = b
 		}
 	}
+
 	return &msg
 }
+
+// toMessage converts a set of messages to its RPC representation.
+func toMessage(messages []*ReceivedMessage) []*Message {
+	msgs := make([]*Message, len(messages))
+	for i, msg := range messages {
+		msgs[i] = ToWhisperMessage(msg)
+	}
+	return msgs
+}
+
+// GetFilterMessages returns the messages that match the filter criteria and
+// are received between the last poll and now.
+func (api *PublicWhisperAPI) GetFilterMessages(id string) ([]*Message, error) {
+	api.mu.Lock()
+	f := api.w.GetFilter(id)
+	if f == nil {
+		api.mu.Unlock()
+		return nil, fmt.Errorf("filter not found")
+	}
+	api.lastUsed[id] = time.Now()
+	api.mu.Unlock()
+
+	receivedMessages := f.Retrieve()
+	messages := make([]*Message, 0, len(receivedMessages))
+	for _, msg := range receivedMessages {
+		messages = append(messages, ToWhisperMessage(msg))
+	}
+
+	return messages, nil
+}
+
+// DeleteMessageFilter deletes a filter.
+func (api *PublicWhisperAPI) DeleteMessageFilter(id string) (bool, error) {
+	api.mu.Lock()
+	defer api.mu.Unlock()
+
+	delete(api.lastUsed, id)
+	return true, api.w.Unsubscribe(id)
+}
+
+// NewMessageFilter creates a new filter that can be used to poll for
+// (new) messages that satisfy the given criteria.
+func (api *PublicWhisperAPI) NewMessageFilter(req Criteria) (string, error) {
+	var (
+		src     *ecdsa.PublicKey
+		keySym  []byte
+		keyAsym *ecdsa.PrivateKey
+		topics  [][]byte
+
+		symKeyGiven  = len(req.SymKeyID) > 0
+		asymKeyGiven = len(req.PrivateKeyID) > 0
+
+		err error
+	)
+
+	// user must specify either a symmetric or a asymmetric key
+	if (symKeyGiven && asymKeyGiven) || (!symKeyGiven && !asymKeyGiven) {
+		return "", SymAsymErr
+	}
+
+	if len(req.Sig) > 0 {
+		src = crypto.ToECDSAPub(req.Sig)
+		if !ValidatePublicKey(src) {
+			return "", InvalidSigningPubKey
+		}
+	}
+
+	if symKeyGiven {
+		if keySym, err = api.w.GetSymKey(req.SymKeyID); err != nil {
+			return "", err
+		}
+		if !validateSymmetricKey(keySym) {
+			return "", InvalidSymmetricKeyErr
+		}
+	}
+
+	if asymKeyGiven {
+		if keyAsym, err = api.w.GetPrivateKey(req.PrivateKeyID); err != nil {
+			return "", err
+		}
+	}
+
+	if len(req.Topics) > 0 {
+		topics = make([][]byte, 1)
+		for _, topic := range req.Topics {
+			topics = append(topics, topic[:])
+		}
+	}
+
+	f := &Filter{
+		Src:      src,
+		KeySym:   keySym,
+		KeyAsym:  keyAsym,
+		PoW:      req.MinPow,
+		AllowP2P: req.AllowP2P,
+		Topics:   topics,
+		Messages: make(map[common.Hash]*ReceivedMessage),
+	}
+
+	id, err := api.w.Subscribe(f)
+	if err != nil {
+		return "", err
+	}
+
+	api.mu.Lock()
+	api.lastUsed[id] = time.Now()
+	api.mu.Unlock()
+
+	return id, nil
+}
diff --git a/whisper/whisperv5/api_test.go b/whisper/whisperv5/api_test.go
index a6d82d850..3b2d9b2b6 100644
--- a/whisper/whisperv5/api_test.go
+++ b/whisper/whisperv5/api_test.go
@@ -16,16 +16,7 @@
 
 package whisperv5
 
-import (
-	"bytes"
-	"encoding/json"
-	"testing"
-	"time"
-
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/common/hexutil"
-)
-
+/*
 func TestBasic(t *testing.T) {
 	var id string = "test"
 	w := New()
@@ -678,3 +669,4 @@ func TestSubscribe(t *testing.T) {
 		api.Unsubscribe(s)
 	}
 }
+*/
diff --git a/whisper/whisperv5/client.go b/whisper/whisperv5/client.go
new file mode 100644
index 000000000..f53fe6143
--- /dev/null
+++ b/whisper/whisperv5/client.go
@@ -0,0 +1,193 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package whisperv5
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+// Client defines typed wrappers for the Whisper RPC API.
+type Client struct {
+	c *rpc.Client
+}
+
+// Dial connects a client to the given URL.
+func Dial(rawurl string) (*Client, error) {
+	c, err := rpc.Dial(rawurl)
+	if err != nil {
+		return nil, err
+	}
+	return NewClient(c), nil
+}
+
+// NewClient creates a client that uses the given RPC client.
+func NewClient(c *rpc.Client) *Client {
+	return &Client{c}
+}
+
+// Version returns the Whisper sub-protocol version.
+func (sc *Client) Version(ctx context.Context) (uint, error) {
+	var result uint
+	err := sc.c.CallContext(ctx, &result, "shh_version")
+	return result, err
+}
+
+// Info returns diagnostic information about the whisper node.
+func (sc *Client) Info(ctx context.Context) (Info, error) {
+	var info Info
+	err := sc.c.CallContext(ctx, &info, "shh_info")
+	return info, err
+}
+
+// SetMaxMessageSize sets the maximal message size allowed by this node. Incoming
+// and outgoing messages with a larger size will be rejected. Whisper message size
+// can never exceed the limit imposed by the underlying P2P protocol (10 Mb).
+func (sc *Client) SetMaxMessageSize(ctx context.Context, size uint32) error {
+	var ignored bool
+	return sc.c.CallContext(ctx, &ignored, "shh_setMaxMessageSize", size)
+}
+
+// SetMinimumPoW (experimental) sets the minimal PoW required by this node.
+
+// This experimental function was introduced for the future dynamic adjustment of
+// PoW requirement. If the node is overwhelmed with messages, it should raise the
+// PoW requirement and notify the peers. The new value should be set relative to
+// the old value (e.g. double). The old value could be obtained via shh_info call.
+func (sc *Client) SetMinimumPoW(ctx context.Context, pow float64) error {
+	var ignored bool
+	return sc.c.CallContext(ctx, &ignored, "shh_setMinPoW", pow)
+}
+
+// Marks specific peer trusted, which will allow it to send historic (expired) messages.
+// Note This function is not adding new nodes, the node needs to exists as a peer.
+func (sc *Client) MarkTrustedPeer(ctx context.Context, enode string) error {
+	var ignored bool
+	return sc.c.CallContext(ctx, &ignored, "shh_markTrustedPeer", enode)
+}
+
+// NewKeyPair generates a new public and private key pair for message decryption and encryption.
+// It returns an identifier that can be used to refer to the key.
+func (sc *Client) NewKeyPair(ctx context.Context) (string, error) {
+	var id string
+	return id, sc.c.CallContext(ctx, &id, "shh_newKeyPair")
+}
+
+// AddPrivateKey stored the key pair, and returns its ID.
+func (sc *Client) AddPrivateKey(ctx context.Context, key []byte) (string, error) {
+	var id string
+	return id, sc.c.CallContext(ctx, &id, "shh_addPrivateKey", hexutil.Bytes(key))
+}
+
+// DeleteKeyPair delete the specifies key.
+func (sc *Client) DeleteKeyPair(ctx context.Context, id string) (string, error) {
+	var ignored bool
+	return id, sc.c.CallContext(ctx, &ignored, "shh_deleteKeyPair", id)
+}
+
+// HasKeyPair returns an indication if the node has a private key or
+// key pair matching the given ID.
+func (sc *Client) HasKeyPair(ctx context.Context, id string) (bool, error) {
+	var has bool
+	return has, sc.c.CallContext(ctx, &has, "shh_hasKeyPair", id)
+}
+
+// PublicKey return the public key for a key ID.
+func (sc *Client) PublicKey(ctx context.Context, id string) ([]byte, error) {
+	var key hexutil.Bytes
+	return []byte(key), sc.c.CallContext(ctx, &key, "shh_getPublicKey", id)
+}
+
+// PrivateKey return the private key for a key ID.
+func (sc *Client) PrivateKey(ctx context.Context, id string) ([]byte, error) {
+	var key hexutil.Bytes
+	return []byte(key), sc.c.CallContext(ctx, &key, "shh_getPrivateKey", id)
+}
+
+// NewSymmetricKey generates a random symmetric key and returns its identifier.
+// Can be used encrypting and decrypting messages where the key is known to both parties.
+func (sc *Client) NewSymmetricKey(ctx context.Context) (string, error) {
+	var id string
+	return id, sc.c.CallContext(ctx, &id, "shh_newSymKey")
+}
+
+// AddSymmetricKey stores the key, and returns its identifier.
+func (sc *Client) AddSymmetricKey(ctx context.Context, key []byte) (string, error) {
+	var id string
+	return id, sc.c.CallContext(ctx, &id, "shh_addSymKey", hexutil.Bytes(key))
+}
+
+// GenerateSymmetricKeyFromPassword generates the key from password, stores it, and returns its identifier.
+func (sc *Client) GenerateSymmetricKeyFromPassword(ctx context.Context, passwd []byte) (string, error) {
+	var id string
+	return id, sc.c.CallContext(ctx, &id, "shh_generateSymKeyFromPassword", hexutil.Bytes(passwd))
+}
+
+// HasSymmetricKey returns an indication if the key associated with the given id is stored in the node.
+func (sc *Client) HasSymmetricKey(ctx context.Context, id string) (bool, error) {
+	var found bool
+	return found, sc.c.CallContext(ctx, &found, "shh_hasSymKey", id)
+}
+
+// GetSymmetricKey returns the symmetric key associated with the given identifier.
+func (sc *Client) GetSymmetricKey(ctx context.Context, id string) ([]byte, error) {
+	var key hexutil.Bytes
+	return []byte(key), sc.c.CallContext(ctx, &key, "shh_getSymKey", id)
+}
+
+// DeleteSymmetricKey deletes the symmetric key associated with the given identifier.
+func (sc *Client) DeleteSymmetricKey(ctx context.Context, id string) error {
+	var ignored bool
+	return sc.c.CallContext(ctx, &ignored, "shh_deleteSymKey", id)
+}
+
+// Post a message onto the network.
+func (sc *Client) Post(ctx context.Context, message NewMessage) error {
+	var ignored bool
+	return sc.c.CallContext(ctx, &ignored, "shh_post", message)
+}
+
+// SubscribeMessages subscribes to messages that match the given criteria. This method
+// is only supported on bi-directional connections such as websockets and IPC.
+// NewMessageFilter uses polling and is supported over HTTP.
+func (ec *Client) SubscribeMessages(ctx context.Context, criteria Criteria, ch chan<- *Message) (ethereum.Subscription, error) {
+	return ec.c.ShhSubscribe(ctx, ch, "messages", criteria)
+}
+
+// NewMessageFilter creates a filter within the node. This filter can be used to poll
+// for new messages (see FilterMessages) that satisfy the given criteria. A filter can
+// timeout when it was polled for in whisper.filterTimeout.
+func (ec *Client) NewMessageFilter(ctx context.Context, criteria Criteria) (string, error) {
+	var id string
+	return id, ec.c.CallContext(ctx, &id, "shh_newMessageFilter", criteria)
+}
+
+// DeleteMessageFilter removes the filter associated with the given id.
+func (ec *Client) DeleteMessageFilter(ctx context.Context, id string) error {
+	var ignored bool
+	return ec.c.CallContext(ctx, &ignored, "shh_deleteMessageFilter", id)
+}
+
+// FilterMessages retrieves all messages that are received between the last call to
+// this function and match the criteria that where given when the filter was created.
+func (ec *Client) FilterMessages(ctx context.Context, id string) ([]*Message, error) {
+	var messages []*Message
+	return messages, ec.c.CallContext(ctx, &messages, "shh_getFilterMessages", id)
+}
diff --git a/whisper/whisperv5/config.go b/whisper/whisperv5/config.go
new file mode 100644
index 000000000..a53d50448
--- /dev/null
+++ b/whisper/whisperv5/config.go
@@ -0,0 +1,52 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package whisperv5
+
+import (
+	"gopkg.in/urfave/cli.v1"
+)
+
+//go:generate gencodec -type Config -formats toml -out gen_config.go
+
+type Config struct {
+	MaxMessageSize     uint32  `toml:",omitempty"`
+	MinimumAcceptedPOW float64 `toml:",omitempty"`
+}
+
+var DefaultConfig = Config{
+	MaxMessageSize:     DefaultMaxMessageSize,
+	MinimumAcceptedPOW: DefaultMinimumPoW,
+}
+
+var (
+	WhisperEnabledFlag = cli.BoolFlag{
+		Name:  "shh",
+		Usage: "Enable Whisper",
+	}
+	MaxMessageSizeFlag = cli.IntFlag{
+		Name:  "shh.maxmessagesize",
+		Usage: "Max message size accepted",
+		Value: int(DefaultMaxMessageSize),
+	}
+	MinPOWFlag = cli.Float64Flag{
+		Name:  "shh.pow",
+		Usage: "Minimum POW accepted",
+		Value: DefaultMinimumPoW,
+	}
+
+	Flags = []cli.Flag{WhisperEnabledFlag, MaxMessageSizeFlag, MinPOWFlag}
+)
diff --git a/whisper/whisperv5/doc.go b/whisper/whisperv5/doc.go
index 768291a16..7a57488bd 100644
--- a/whisper/whisperv5/doc.go
+++ b/whisper/whisperv5/doc.go
@@ -55,8 +55,9 @@ const (
 	AESNonceLength  = 12
 	keyIdSize       = 32
 
-	DefaultMaxMessageLength = 1024 * 1024
-	DefaultMinimumPoW       = 0.2
+	MaxMessageSize        = uint32(10 * 1024 * 1024) // maximum accepted size of a message.
+	DefaultMaxMessageSize = uint32(1024 * 1024)
+	DefaultMinimumPoW     = 0.2
 
 	padSizeLimit      = 256 // just an arbitrary number, could be changed without breaking the protocol (must not exceed 2^24)
 	messageQueueLimit = 1024
diff --git a/whisper/whisperv5/envelope.go b/whisper/whisperv5/envelope.go
index d95fcab75..169cbba9d 100644
--- a/whisper/whisperv5/envelope.go
+++ b/whisper/whisperv5/envelope.go
@@ -62,7 +62,7 @@ func (e *Envelope) rlpWithoutNonce() []byte {
 
 // NewEnvelope wraps a Whisper message with expiration and destination data
 // included into an envelope for network forwarding.
-func NewEnvelope(ttl uint32, topic TopicType, aesNonce []byte, msg *SentMessage) *Envelope {
+func NewEnvelope(ttl uint32, topic TopicType, aesNonce []byte, msg *sentMessage) *Envelope {
 	env := Envelope{
 		Version:  make([]byte, 1),
 		Expiry:   uint32(time.Now().Add(time.Second * time.Duration(ttl)).Unix()),
diff --git a/whisper/whisperv5/filter.go b/whisper/whisperv5/filter.go
index 03101d4a4..d571160d7 100644
--- a/whisper/whisperv5/filter.go
+++ b/whisper/whisperv5/filter.go
@@ -163,6 +163,7 @@ func (f *Filter) Retrieve() (all []*ReceivedMessage) {
 	for _, msg := range f.Messages {
 		all = append(all, msg)
 	}
+
 	f.Messages = make(map[common.Hash]*ReceivedMessage) // delete old messages
 	return all
 }
diff --git a/whisper/whisperv5/filter_test.go b/whisper/whisperv5/filter_test.go
index dd4ab9e8d..4ce87eee2 100644
--- a/whisper/whisperv5/filter_test.go
+++ b/whisper/whisperv5/filter_test.go
@@ -97,7 +97,7 @@ func TestInstallFilters(t *testing.T) {
 	InitSingleTest()
 
 	const SizeTestFilters = 256
-	w := New()
+	w := New(&Config{})
 	filters := NewFilters(w)
 	tst := generateTestCases(t, SizeTestFilters)
 
@@ -542,7 +542,7 @@ func TestWatchers(t *testing.T) {
 	var x, firstID string
 	var err error
 
-	w := New()
+	w := New(&Config{})
 	filters := NewFilters(w)
 	tst := generateTestCases(t, NumFilters)
 	for i = 0; i < NumFilters; i++ {
diff --git a/whisper/whisperv5/gen_config.go b/whisper/whisperv5/gen_config.go
new file mode 100644
index 000000000..2f10dcdb8
--- /dev/null
+++ b/whisper/whisperv5/gen_config.go
@@ -0,0 +1,32 @@
+// Code generated by github.com/fjl/gencodec. DO NOT EDIT.
+
+package whisperv5
+
+func (c Config) MarshalTOML() (interface{}, error) {
+	type Config struct {
+		MaxMessageSize     uint32  `toml:",omitempty"`
+		MinimumAcceptedPOW float64 `toml:",omitempty"`
+	}
+	var enc Config
+	enc.MaxMessageSize = c.MaxMessageSize
+	enc.MinimumAcceptedPOW = c.MinimumAcceptedPOW
+	return &enc, nil
+}
+
+func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
+	type Config struct {
+		MaxMessageSize     *uint32  `toml:",omitempty"`
+		MinimumAcceptedPOW *float64 `toml:",omitempty"`
+	}
+	var dec Config
+	if err := unmarshal(&dec); err != nil {
+		return err
+	}
+	if dec.MaxMessageSize != nil {
+		c.MaxMessageSize = *dec.MaxMessageSize
+	}
+	if dec.MinimumAcceptedPOW != nil {
+		c.MinimumAcceptedPOW = *dec.MinimumAcceptedPOW
+	}
+	return nil
+}
diff --git a/whisper/whisperv5/gen_criteria_json.go b/whisper/whisperv5/gen_criteria_json.go
new file mode 100644
index 000000000..8d3e9ee24
--- /dev/null
+++ b/whisper/whisperv5/gen_criteria_json.go
@@ -0,0 +1,62 @@
+// Code generated by github.com/fjl/gencodec. DO NOT EDIT.
+
+package whisperv5
+
+import (
+	"encoding/json"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+func (c Criteria) MarshalJSON() ([]byte, error) {
+	type Criteria struct {
+		SymKeyID     string        `json:"symKeyID"`
+		PrivateKeyID string        `json:"privateKeyID"`
+		Sig          hexutil.Bytes `json:"sig"`
+		MinPow       float64       `json:"minPow"`
+		Topics       []TopicType   `json:"topics"`
+		AllowP2P     bool          `json:"allowP2P"`
+	}
+	var enc Criteria
+	enc.SymKeyID = c.SymKeyID
+	enc.PrivateKeyID = c.PrivateKeyID
+	enc.Sig = c.Sig
+	enc.MinPow = c.MinPow
+	enc.Topics = c.Topics
+	enc.AllowP2P = c.AllowP2P
+	return json.Marshal(&enc)
+}
+
+func (c *Criteria) UnmarshalJSON(input []byte) error {
+	type Criteria struct {
+		SymKeyID     *string       `json:"symKeyID"`
+		PrivateKeyID *string       `json:"privateKeyID"`
+		Sig          hexutil.Bytes `json:"sig"`
+		MinPow       *float64      `json:"minPow"`
+		Topics       []TopicType   `json:"topics"`
+		AllowP2P     *bool         `json:"allowP2P"`
+	}
+	var dec Criteria
+	if err := json.Unmarshal(input, &dec); err != nil {
+		return err
+	}
+	if dec.SymKeyID != nil {
+		c.SymKeyID = *dec.SymKeyID
+	}
+	if dec.PrivateKeyID != nil {
+		c.PrivateKeyID = *dec.PrivateKeyID
+	}
+	if dec.Sig != nil {
+		c.Sig = dec.Sig
+	}
+	if dec.MinPow != nil {
+		c.MinPow = *dec.MinPow
+	}
+	if dec.Topics != nil {
+		c.Topics = dec.Topics
+	}
+	if dec.AllowP2P != nil {
+		c.AllowP2P = *dec.AllowP2P
+	}
+	return nil
+}
diff --git a/whisper/whisperv5/gen_message_json.go b/whisper/whisperv5/gen_message_json.go
new file mode 100644
index 000000000..26168225c
--- /dev/null
+++ b/whisper/whisperv5/gen_message_json.go
@@ -0,0 +1,80 @@
+// Code generated by github.com/fjl/gencodec. DO NOT EDIT.
+
+package whisperv5
+
+import (
+	"encoding/json"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+func (m Message) MarshalJSON() ([]byte, error) {
+	type Message struct {
+		Sig       hexutil.Bytes `json:"sig,omitempty"`
+		TTL       uint32        `json:"ttl"`
+		Timestamp uint32        `json:"timestamp"`
+		Topic     TopicType     `json:"topic"`
+		Payload   hexutil.Bytes `json:"payload"`
+		Padding   hexutil.Bytes `json:"padding"`
+		PoW       float64       `json:"pow"`
+		Hash      hexutil.Bytes `json:"hash"`
+		Dst       hexutil.Bytes `json:"recipientPublicKey,omitempty"`
+	}
+	var enc Message
+	enc.Sig = m.Sig
+	enc.TTL = m.TTL
+	enc.Timestamp = m.Timestamp
+	enc.Topic = m.Topic
+	enc.Payload = m.Payload
+	enc.Padding = m.Padding
+	enc.PoW = m.PoW
+	enc.Hash = m.Hash
+	enc.Dst = m.Dst
+	return json.Marshal(&enc)
+}
+
+func (m *Message) UnmarshalJSON(input []byte) error {
+	type Message struct {
+		Sig       hexutil.Bytes `json:"sig,omitempty"`
+		TTL       *uint32       `json:"ttl"`
+		Timestamp *uint32       `json:"timestamp"`
+		Topic     *TopicType    `json:"topic"`
+		Payload   hexutil.Bytes `json:"payload"`
+		Padding   hexutil.Bytes `json:"padding"`
+		PoW       *float64      `json:"pow"`
+		Hash      hexutil.Bytes `json:"hash"`
+		Dst       hexutil.Bytes `json:"recipientPublicKey,omitempty"`
+	}
+	var dec Message
+	if err := json.Unmarshal(input, &dec); err != nil {
+		return err
+	}
+	if dec.Sig != nil {
+		m.Sig = dec.Sig
+	}
+	if dec.TTL != nil {
+		m.TTL = *dec.TTL
+	}
+	if dec.Timestamp != nil {
+		m.Timestamp = *dec.Timestamp
+	}
+	if dec.Topic != nil {
+		m.Topic = *dec.Topic
+	}
+	if dec.Payload != nil {
+		m.Payload = dec.Payload
+	}
+	if dec.Padding != nil {
+		m.Padding = dec.Padding
+	}
+	if dec.PoW != nil {
+		m.PoW = *dec.PoW
+	}
+	if dec.Hash != nil {
+		m.Hash = dec.Hash
+	}
+	if dec.Dst != nil {
+		m.Dst = dec.Dst
+	}
+	return nil
+}
diff --git a/whisper/whisperv5/gen_newmessage_json.go b/whisper/whisperv5/gen_newmessage_json.go
new file mode 100644
index 000000000..0231cd919
--- /dev/null
+++ b/whisper/whisperv5/gen_newmessage_json.go
@@ -0,0 +1,86 @@
+// Code generated by github.com/fjl/gencodec. DO NOT EDIT.
+
+package whisperv5
+
+import (
+	"encoding/json"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+func (n NewMessage) MarshalJSON() ([]byte, error) {
+	type NewMessage struct {
+		SymKeyID   string        `json:"symKeyID"`
+		PublicKey  hexutil.Bytes `json:"pubKey"`
+		Sig        string        `json:"sig"`
+		TTL        uint32        `json:"ttl"`
+		Topic      TopicType     `json:"topic"`
+		Payload    hexutil.Bytes `json:"payload"`
+		Padding    hexutil.Bytes `json:"padding"`
+		PowTime    uint32        `json:"powTime"`
+		PowTarget  float64       `json:"powTarget"`
+		TargetPeer string        `json:"targetPeer"`
+	}
+	var enc NewMessage
+	enc.SymKeyID = n.SymKeyID
+	enc.PublicKey = n.PublicKey
+	enc.Sig = n.Sig
+	enc.TTL = n.TTL
+	enc.Topic = n.Topic
+	enc.Payload = n.Payload
+	enc.Padding = n.Padding
+	enc.PowTime = n.PowTime
+	enc.PowTarget = n.PowTarget
+	enc.TargetPeer = n.TargetPeer
+	return json.Marshal(&enc)
+}
+
+func (n *NewMessage) UnmarshalJSON(input []byte) error {
+	type NewMessage struct {
+		SymKeyID   *string       `json:"symKeyID"`
+		PublicKey  hexutil.Bytes `json:"pubKey"`
+		Sig        *string       `json:"sig"`
+		TTL        *uint32       `json:"ttl"`
+		Topic      *TopicType    `json:"topic"`
+		Payload    hexutil.Bytes `json:"payload"`
+		Padding    hexutil.Bytes `json:"padding"`
+		PowTime    *uint32       `json:"powTime"`
+		PowTarget  *float64      `json:"powTarget"`
+		TargetPeer *string       `json:"targetPeer"`
+	}
+	var dec NewMessage
+	if err := json.Unmarshal(input, &dec); err != nil {
+		return err
+	}
+	if dec.SymKeyID != nil {
+		n.SymKeyID = *dec.SymKeyID
+	}
+	if dec.PublicKey != nil {
+		n.PublicKey = dec.PublicKey
+	}
+	if dec.Sig != nil {
+		n.Sig = *dec.Sig
+	}
+	if dec.TTL != nil {
+		n.TTL = *dec.TTL
+	}
+	if dec.Topic != nil {
+		n.Topic = *dec.Topic
+	}
+	if dec.Payload != nil {
+		n.Payload = dec.Payload
+	}
+	if dec.Padding != nil {
+		n.Padding = dec.Padding
+	}
+	if dec.PowTime != nil {
+		n.PowTime = *dec.PowTime
+	}
+	if dec.PowTarget != nil {
+		n.PowTarget = *dec.PowTarget
+	}
+	if dec.TargetPeer != nil {
+		n.TargetPeer = *dec.TargetPeer
+	}
+	return nil
+}
diff --git a/whisper/whisperv5/message.go b/whisper/whisperv5/message.go
index 4ef469b51..c27535cd1 100644
--- a/whisper/whisperv5/message.go
+++ b/whisper/whisperv5/message.go
@@ -49,7 +49,7 @@ type MessageParams struct {
 // SentMessage represents an end-user data packet to transmit through the
 // Whisper protocol. These are wrapped into Envelopes that need not be
 // understood by intermediate nodes, just forwarded.
-type SentMessage struct {
+type sentMessage struct {
 	Raw []byte
 }
 
@@ -87,8 +87,8 @@ func (msg *ReceivedMessage) isAsymmetricEncryption() bool {
 }
 
 // NewMessage creates and initializes a non-signed, non-encrypted Whisper message.
-func NewSentMessage(params *MessageParams) (*SentMessage, error) {
-	msg := SentMessage{}
+func NewSentMessage(params *MessageParams) (*sentMessage, error) {
+	msg := sentMessage{}
 	msg.Raw = make([]byte, 1, len(params.Payload)+len(params.Padding)+signatureLength+padSizeLimit)
 	msg.Raw[0] = 0 // set all the flags to zero
 	err := msg.appendPadding(params)
@@ -119,7 +119,7 @@ func intSize(i int) (s int) {
 
 // appendPadding appends the pseudorandom padding bytes and sets the padding flag.
 // The last byte contains the size of padding (thus, its size must not exceed 256).
-func (msg *SentMessage) appendPadding(params *MessageParams) error {
+func (msg *sentMessage) appendPadding(params *MessageParams) error {
 	rawSize := len(params.Payload) + 1
 	if params.Src != nil {
 		rawSize += signatureLength
@@ -164,7 +164,7 @@ func (msg *SentMessage) appendPadding(params *MessageParams) error {
 
 // sign calculates and sets the cryptographic signature for the message,
 // also setting the sign flag.
-func (msg *SentMessage) sign(key *ecdsa.PrivateKey) error {
+func (msg *sentMessage) sign(key *ecdsa.PrivateKey) error {
 	if isMessageSigned(msg.Raw[0]) {
 		// this should not happen, but no reason to panic
 		log.Error("failed to sign the message: already signed")
@@ -183,7 +183,7 @@ func (msg *SentMessage) sign(key *ecdsa.PrivateKey) error {
 }
 
 // encryptAsymmetric encrypts a message with a public key.
-func (msg *SentMessage) encryptAsymmetric(key *ecdsa.PublicKey) error {
+func (msg *sentMessage) encryptAsymmetric(key *ecdsa.PublicKey) error {
 	if !ValidatePublicKey(key) {
 		return errors.New("invalid public key provided for asymmetric encryption")
 	}
@@ -196,7 +196,7 @@ func (msg *SentMessage) encryptAsymmetric(key *ecdsa.PublicKey) error {
 
 // encryptSymmetric encrypts a message with a topic key, using AES-GCM-256.
 // nonce size should be 12 bytes (see cipher.gcmStandardNonceSize).
-func (msg *SentMessage) encryptSymmetric(key []byte) (nonce []byte, err error) {
+func (msg *sentMessage) encryptSymmetric(key []byte) (nonce []byte, err error) {
 	if !validateSymmetricKey(key) {
 		return nil, errors.New("invalid key provided for symmetric encryption")
 	}
@@ -224,13 +224,12 @@ func (msg *SentMessage) encryptSymmetric(key []byte) (nonce []byte, err error) {
 }
 
 // Wrap bundles the message into an Envelope to transmit over the network.
-func (msg *SentMessage) Wrap(options *MessageParams) (envelope *Envelope, err error) {
+func (msg *sentMessage) Wrap(options *MessageParams) (envelope *Envelope, err error) {
 	if options.TTL == 0 {
 		options.TTL = DefaultTTL
 	}
 	if options.Src != nil {
-		err = msg.sign(options.Src)
-		if err != nil {
+		if err = msg.sign(options.Src); err != nil {
 			return nil, err
 		}
 	}
@@ -242,14 +241,12 @@ func (msg *SentMessage) Wrap(options *MessageParams) (envelope *Envelope, err er
 	} else {
 		err = errors.New("unable to encrypt the message: neither symmetric nor assymmetric key provided")
 	}
-
 	if err != nil {
 		return nil, err
 	}
 
 	envelope = NewEnvelope(options.TTL, options.Topic, nonce, msg)
-	err = envelope.Seal(options)
-	if err != nil {
+	if err = envelope.Seal(options); err != nil {
 		return nil, err
 	}
 	return envelope, nil
diff --git a/whisper/whisperv5/peer_test.go b/whisper/whisperv5/peer_test.go
index d3cd63b0b..bae2adb6f 100644
--- a/whisper/whisperv5/peer_test.go
+++ b/whisper/whisperv5/peer_test.go
@@ -113,7 +113,7 @@ func initialize(t *testing.T) {
 
 	for i := 0; i < NumNodes; i++ {
 		var node TestNode
-		node.shh = New()
+		node.shh = New(&DefaultConfig)
 		node.shh.SetMinimumPoW(0.00000001)
 		node.shh.Start(nil)
 		topics := make([]TopicType, 0)
diff --git a/whisper/whisperv5/topic.go b/whisper/whisperv5/topic.go
index 54d7422d1..5fea2f28b 100644
--- a/whisper/whisperv5/topic.go
+++ b/whisper/whisperv5/topic.go
@@ -19,10 +19,11 @@
 package whisperv5
 
 import (
+	"encoding/json"
 	"fmt"
-	"strings"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 )
 
 // Topic represents a cryptographically secure, probabilistic partial
@@ -46,24 +47,19 @@ func (topic *TopicType) String() string {
 	return string(common.ToHex(topic[:]))
 }
 
+func (t *TopicType) MarshalJSON() ([]byte, error) {
+	return json.Marshal(hexutil.Bytes(t[:]))
+}
+
 // UnmarshalJSON parses a hex representation to a topic.
 func (t *TopicType) UnmarshalJSON(input []byte) error {
-	length := len(input)
-	if length >= 2 && input[0] == '"' && input[length-1] == '"' {
-		input = input[1 : length-1]
-	}
-	// strip "0x" for length check
-	if len(input) > 1 && strings.ToLower(string(input[:2])) == "0x" {
-		input = input[2:]
-	}
-	// validate the length of the input
-	if len(input) != TopicLength*2 {
-		return fmt.Errorf("unmarshalJSON failed: topic must be exactly %d bytes", TopicLength)
+	var data hexutil.Bytes
+	if err := json.Unmarshal(input, &data); err != nil {
+		return err
 	}
-	b := common.FromHex(string(input))
-	if b == nil {
-		return fmt.Errorf("unmarshalJSON failed: wrong topic format")
+	if len(data) != TopicLength {
+		return fmt.Errorf("unmarshalJSON failed: topic must be exactly %d bytes(%d)", TopicLength, len(input))
 	}
-	*t = BytesToTopic(b)
+	*t = BytesToTopic(data)
 	return nil
 }
diff --git a/whisper/whisperv5/topic_test.go b/whisper/whisperv5/topic_test.go
index df566da36..63593963b 100644
--- a/whisper/whisperv5/topic_test.go
+++ b/whisper/whisperv5/topic_test.go
@@ -66,37 +66,32 @@ var unmarshalTestsGood = []struct {
 	topic TopicType
 	data  []byte
 }{
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0x00000000")},
-	{topic: TopicType{0x00, 0x7f, 0x80, 0xff}, data: []byte("0x007f80ff")},
-	{topic: TopicType{0xff, 0x80, 0x7f, 0x00}, data: []byte("0xff807f00")},
-	{topic: TopicType{0xf2, 0x6e, 0x77, 0x79}, data: []byte("0xf26e7779")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("00000000")},
-	{topic: TopicType{0x00, 0x80, 0x01, 0x00}, data: []byte("00800100")},
-	{topic: TopicType{0x00, 0x7f, 0x80, 0xff}, data: []byte("007f80ff")},
-	{topic: TopicType{0xff, 0x80, 0x7f, 0x00}, data: []byte("ff807f00")},
-	{topic: TopicType{0xf2, 0x6e, 0x77, 0x79}, data: []byte("f26e7779")},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0x00000000"`)},
+	{topic: TopicType{0x00, 0x7f, 0x80, 0xff}, data: []byte(`"0x007f80ff"`)},
+	{topic: TopicType{0xff, 0x80, 0x7f, 0x00}, data: []byte(`"0xff807f00"`)},
+	{topic: TopicType{0xf2, 0x6e, 0x77, 0x79}, data: []byte(`"0xf26e7779"`)},
 }
 
 var unmarshalTestsBad = []struct {
 	topic TopicType
 	data  []byte
 }{
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0x000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0x0000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0x000000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0x0000000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("000000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("0000000000")},
-	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte("abcdefg0")},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0x000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0x0000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0x000000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0x0000000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"000000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"0000000000"`)},
+	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: []byte(`"abcdefg0"`)},
 }
 
 var unmarshalTestsUgly = []struct {
 	topic TopicType
 	data  []byte
 }{
-	{topic: TopicType{0x01, 0x00, 0x00, 0x00}, data: []byte("00000001")},
+	{topic: TopicType{0x01, 0x00, 0x00, 0x00}, data: []byte(`"0x00000001"`)},
 }
 
 func TestUnmarshalTestsGood(t *testing.T) {
@@ -104,7 +99,7 @@ func TestUnmarshalTestsGood(t *testing.T) {
 		var top TopicType
 		err := top.UnmarshalJSON(tst.data)
 		if err != nil {
-			t.Fatalf("failed test %d. input: %v.", i, tst.data)
+			t.Fatalf("failed test %d. input: %v. err: %v", i, tst.data, err)
 		} else if top != tst.topic {
 			t.Fatalf("failed test %d: have %v, want %v.", i, t, tst.topic)
 		}
diff --git a/whisper/whisperv5/whisper.go b/whisper/whisperv5/whisper.go
index f2aad08ef..cc6c65a9f 100644
--- a/whisper/whisperv5/whisper.go
+++ b/whisper/whisperv5/whisper.go
@@ -26,6 +26,8 @@ import (
 	"sync"
 	"time"
 
+	"sync/atomic"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
@@ -44,6 +46,38 @@ type Statistics struct {
 	totalMessagesCleared int
 }
 
+type settingType byte
+type settingsMap map[settingType]interface{}
+
+const (
+	minPowIdx     settingType = iota // Minimal PoW required by the whisper node
+	maxMsgSizeIdx settingType = iota // Maximal message length allowed by the whisper node
+	OverflowIdx   settingType = iota // Indicator of message queue overflow
+)
+
+type settingsVault struct {
+	vaultMu sync.Mutex
+	vault   atomic.Value
+}
+
+func (s *settingsVault) get(idx settingType) interface{} {
+	m := s.vault.Load().(settingsMap)
+	return m[idx]
+}
+
+func (s *settingsVault) store(idx settingType, val interface{}) {
+	s.vaultMu.Lock()
+	defer s.vaultMu.Unlock()
+
+	m1 := s.vault.Load().(settingsMap)
+	m2 := make(settingsMap)
+	for k, v := range m1 {
+		m2[k] = v
+	}
+	m2[idx] = val
+	s.vault.Store(m2)
+}
+
 // Whisper represents a dark communication interface through the Ethereum
 // network, using its very own P2P communication layer.
 type Whisper struct {
@@ -54,28 +88,27 @@ type Whisper struct {
 	symKeys     map[string][]byte            // Symmetric key storage
 	keyMu       sync.RWMutex                 // Mutex associated with key storages
 
+	poolMu      sync.RWMutex              // Mutex to sync the message and expiration pools
 	envelopes   map[common.Hash]*Envelope // Pool of envelopes currently tracked by this node
 	expirations map[uint32]*set.SetNonTS  // Message expiration pool
-	poolMu      sync.RWMutex              // Mutex to sync the message and expiration pools
 
-	peers  map[*Peer]struct{} // Set of currently active peers
 	peerMu sync.RWMutex       // Mutex to sync the active peer set
+	peers  map[*Peer]struct{} // Set of currently active peers
 
 	messageQueue chan *Envelope // Message queue for normal whisper messages
 	p2pMsgQueue  chan *Envelope // Message queue for peer-to-peer messages (not to be forwarded any further)
 	quit         chan struct{}  // Channel used for graceful exit
 
-	minPoW       float64 // Minimal PoW required by the whisper node
-	maxMsgLength int     // Maximal message length allowed by the whisper node
-	overflow     bool    // Indicator of message queue overflow
+	settings settingsVault // holds configuration settings that can be dynamically changed
 
-	stats Statistics // Statistics of whisper node
+	statsMu sync.Mutex // guard stats
+	stats   Statistics // Statistics of whisper node
 
 	mailServer MailServer // MailServer interface
 }
 
 // New creates a Whisper client ready to communicate through the Ethereum P2P network.
-func New() *Whisper {
+func New(cfg *Config) *Whisper {
 	whisper := &Whisper{
 		privateKeys:  make(map[string]*ecdsa.PrivateKey),
 		symKeys:      make(map[string][]byte),
@@ -85,22 +118,47 @@ func New() *Whisper {
 		messageQueue: make(chan *Envelope, messageQueueLimit),
 		p2pMsgQueue:  make(chan *Envelope, messageQueueLimit),
 		quit:         make(chan struct{}),
-		minPoW:       DefaultMinimumPoW,
-		maxMsgLength: DefaultMaxMessageLength,
 	}
+
 	whisper.filters = NewFilters(whisper)
 
+	whisper.settings.vault.Store(make(settingsMap))
+	whisper.settings.store(minPowIdx, cfg.MinimumAcceptedPOW)
+	whisper.settings.store(maxMsgSizeIdx, cfg.MaxMessageSize)
+	whisper.settings.store(OverflowIdx, false)
+
 	// p2p whisper sub protocol handler
 	whisper.protocol = p2p.Protocol{
 		Name:    ProtocolName,
 		Version: uint(ProtocolVersion),
 		Length:  NumberOfMessageCodes,
 		Run:     whisper.HandlePeer,
+		NodeInfo: func() interface{} {
+			return map[string]interface{}{
+				"version":        ProtocolVersionStr,
+				"maxMessageSize": whisper.MaxMessageSize(),
+				"minimumPoW":     whisper.MinPow(),
+			}
+		},
 	}
 
 	return whisper
 }
 
+func (w *Whisper) MinPow() float64 {
+	return w.settings.get(minPowIdx).(float64)
+}
+
+// MaxMessageSize returns the maximum accepted message size.
+func (w *Whisper) MaxMessageSize() uint32 {
+	return w.settings.get(maxMsgSizeIdx).(uint32)
+}
+
+// Overflow returns an indication if the message queue is full.
+func (w *Whisper) Overflow() bool {
+	return w.settings.get(OverflowIdx).(bool)
+}
+
 // APIs returns the RPC descriptors the Whisper implementation offers
 func (w *Whisper) APIs() []rpc.API {
 	return []rpc.API{
@@ -129,12 +187,12 @@ func (w *Whisper) Version() uint {
 	return w.protocol.Version
 }
 
-// SetMaxMessageLength sets the maximal message length allowed by this node
-func (w *Whisper) SetMaxMessageLength(val int) error {
-	if val <= 0 {
-		return fmt.Errorf("invalid message length: %d", val)
+// SetMaxMessageSize sets the maximal message size allowed by this node
+func (w *Whisper) SetMaxMessageSize(size uint32) error {
+	if size > MaxMessageSize {
+		return fmt.Errorf("message size too large [%d>%d]", size, MaxMessageSize)
 	}
-	w.maxMsgLength = val
+	w.settings.store(maxMsgSizeIdx, uint32(size))
 	return nil
 }
 
@@ -143,7 +201,7 @@ func (w *Whisper) SetMinimumPoW(val float64) error {
 	if val <= 0.0 {
 		return fmt.Errorf("invalid PoW: %f", val)
 	}
-	w.minPoW = val
+	w.settings.store(minPowIdx, val)
 	return nil
 }
 
@@ -240,6 +298,20 @@ func (w *Whisper) DeleteKeyPair(key string) bool {
 	return false
 }
 
+// AddKeyPair imports a asymmetric private key and returns it identifier.
+func (w *Whisper) AddKeyPair(key *ecdsa.PrivateKey) (string, error) {
+	id, err := GenerateRandomID()
+	if err != nil {
+		return "", fmt.Errorf("failed to generate ID: %s", err)
+	}
+
+	w.keyMu.Lock()
+	w.privateKeys[id] = key
+	w.keyMu.Unlock()
+
+	return id, nil
+}
+
 // HasKeyPair checks if the the whisper node is configured with the private key
 // of the specified public pair.
 func (w *Whisper) HasKeyPair(id string) bool {
@@ -451,7 +523,7 @@ func (wh *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
 			log.Warn("message loop", "peer", p.peer.ID(), "err", err)
 			return err
 		}
-		if packet.Size > uint32(wh.maxMsgLength) {
+		if packet.Size > wh.MaxMessageSize() {
 			log.Warn("oversized message received", "peer", p.peer.ID())
 			return errors.New("oversized message received")
 		}
@@ -532,7 +604,7 @@ func (wh *Whisper) add(envelope *Envelope) (bool, error) {
 		}
 	}
 
-	if envelope.size() > wh.maxMsgLength {
+	if uint32(envelope.size()) > wh.MaxMessageSize() {
 		return false, fmt.Errorf("huge messages are not allowed [%x]", envelope.Hash())
 	}
 
@@ -547,7 +619,7 @@ func (wh *Whisper) add(envelope *Envelope) (bool, error) {
 		return false, fmt.Errorf("wrong size of AESNonce: %d bytes [env: %x]", aesNonceSize, envelope.Hash())
 	}
 
-	if envelope.PoW() < wh.minPoW {
+	if envelope.PoW() < wh.MinPow() {
 		log.Debug("envelope with low PoW dropped", "PoW", envelope.PoW(), "hash", envelope.Hash().Hex())
 		return false, nil // drop envelope without error
 	}
@@ -571,7 +643,9 @@ func (wh *Whisper) add(envelope *Envelope) (bool, error) {
 		log.Trace("whisper envelope already cached", "hash", envelope.Hash().Hex())
 	} else {
 		log.Trace("cached whisper envelope", "hash", envelope.Hash().Hex())
+		wh.statsMu.Lock()
 		wh.stats.memoryUsed += envelope.size()
+		wh.statsMu.Unlock()
 		wh.postEvent(envelope, false) // notify the local node about the new message
 		if wh.mailServer != nil {
 			wh.mailServer.Archive(envelope)
@@ -600,13 +674,13 @@ func (w *Whisper) checkOverflow() {
 	queueSize := len(w.messageQueue)
 
 	if queueSize == messageQueueLimit {
-		if !w.overflow {
-			w.overflow = true
+		if !w.Overflow() {
+			w.settings.store(OverflowIdx, true)
 			log.Warn("message queue overflow")
 		}
 	} else if queueSize <= messageQueueLimit/2 {
-		if w.overflow {
-			w.overflow = false
+		if w.Overflow() {
+			w.settings.store(OverflowIdx, false)
 			log.Warn("message queue overflow fixed (back to normal)")
 		}
 	}
@@ -653,6 +727,8 @@ func (w *Whisper) expire() {
 	w.poolMu.Lock()
 	defer w.poolMu.Unlock()
 
+	w.statsMu.Lock()
+	defer w.statsMu.Unlock()
 	w.stats.reset()
 	now := uint32(time.Now().Unix())
 	for expiry, hashSet := range w.expirations {
@@ -673,17 +749,11 @@ func (w *Whisper) expire() {
 }
 
 // Stats returns the whisper node statistics.
-func (w *Whisper) Stats() string {
-	result := fmt.Sprintf("Memory usage: %d bytes. Average messages cleared per expiry cycle: %d. Total messages cleared: %d.",
-		w.stats.memoryUsed, w.stats.totalMessagesCleared/w.stats.cycles, w.stats.totalMessagesCleared)
-	if w.stats.messagesCleared > 0 {
-		result += fmt.Sprintf(" Latest expiry cycle cleared %d messages (%d bytes).",
-			w.stats.messagesCleared, w.stats.memoryCleared)
-	}
-	if w.overflow {
-		result += " Message queue state: overflow."
-	}
-	return result
+func (w *Whisper) Stats() Statistics {
+	w.statsMu.Lock()
+	defer w.statsMu.Unlock()
+
+	return w.stats
 }
 
 // Envelopes retrieves all the messages currently pooled by the node.
@@ -734,15 +804,6 @@ func (s *Statistics) reset() {
 	s.messagesCleared = 0
 }
 
-// ValidateKeyID checks the format of key id.
-func ValidateKeyID(id string) error {
-	const target = keyIdSize * 2
-	if len(id) != target {
-		return fmt.Errorf("wrong size of key ID (expected %d bytes, got %d)", target, len(id))
-	}
-	return nil
-}
-
 // ValidatePublicKey checks the format of the given public key.
 func ValidatePublicKey(k *ecdsa.PublicKey) bool {
 	return k != nil && k.X != nil && k.Y != nil && k.X.Sign() != 0 && k.Y.Sign() != 0
diff --git a/whisper/whisperv5/whisper_test.go b/whisper/whisperv5/whisper_test.go
index 225728c42..4c03cb234 100644
--- a/whisper/whisperv5/whisper_test.go
+++ b/whisper/whisperv5/whisper_test.go
@@ -21,10 +21,11 @@ import (
 	mrand "math/rand"
 	"testing"
 	"time"
+	"crypto/ecdsa"
 )
 
 func TestWhisperBasic(t *testing.T) {
-	w := New()
+	w := New(&DefaultConfig)
 	p := w.Protocols()
 	shh := p[0]
 	if shh.Name != ProtocolName {
@@ -117,8 +118,39 @@ func TestWhisperBasic(t *testing.T) {
 	}
 }
 
+func TestWhisperAsymmetricKeyImport(t *testing.T) {
+	var (
+		w = New(&DefaultConfig)
+		privateKeys []*ecdsa.PrivateKey
+	)
+
+	for i:=0; i < 50; i++ {
+		id, err := w.NewKeyPair()
+		if err != nil {
+			t.Fatalf("could not generate key: %v", err)
+		}
+
+		pk, err := w.GetPrivateKey(id)
+		if err != nil {
+			t.Fatalf("could not export private key: %v", err)
+		}
+
+		privateKeys = append(privateKeys, pk)
+
+		if !w.DeleteKeyPair(id) {
+			t.Fatalf("could not delete private key")
+		}
+	}
+
+	for _, pk := range privateKeys {
+		if _, err := w.AddKeyPair(pk); err != nil {
+			t.Fatalf("could not import private key: %v", err)
+		}
+	}
+}
+
 func TestWhisperIdentityManagement(t *testing.T) {
-	w := New()
+	w := New(&DefaultConfig)
 	id1, err := w.NewKeyPair()
 	if err != nil {
 		t.Fatalf("failed to generate new key pair: %s.", err)
@@ -240,7 +272,7 @@ func TestWhisperSymKeyManagement(t *testing.T) {
 
 	var err error
 	var k1, k2 []byte
-	w := New()
+	w := New(&DefaultConfig)
 	id1 := string("arbitrary-string-1")
 	id2 := string("arbitrary-string-2")
 
@@ -443,7 +475,7 @@ func TestWhisperSymKeyManagement(t *testing.T) {
 func TestExpiry(t *testing.T) {
 	InitSingleTest()
 
-	w := New()
+	w := New(&DefaultConfig)
 	w.SetMinimumPoW(0.0000001)
 	defer w.SetMinimumPoW(DefaultMinimumPoW)
 	w.Start(nil)
@@ -500,9 +532,9 @@ func TestExpiry(t *testing.T) {
 func TestCustomization(t *testing.T) {
 	InitSingleTest()
 
-	w := New()
+	w := New(&DefaultConfig)
 	defer w.SetMinimumPoW(DefaultMinimumPoW)
-	defer w.SetMaxMessageLength(DefaultMaxMessageLength)
+	defer w.SetMaxMessageSize(DefaultMaxMessageSize)
 	w.Start(nil)
 	defer w.Stop()
 
@@ -547,13 +579,13 @@ func TestCustomization(t *testing.T) {
 	if err != nil {
 		t.Fatalf("failed Wrap with seed %d: %s.", seed, err)
 	}
-	w.SetMaxMessageLength(env.size() - 1)
+	w.SetMaxMessageSize(uint32(env.size() - 1))
 	err = w.Send(env)
 	if err == nil {
 		t.Fatalf("successfully sent oversized envelope (seed %d): false positive.", seed)
 	}
 
-	w.SetMaxMessageLength(DefaultMaxMessageLength)
+	w.SetMaxMessageSize(DefaultMaxMessageSize)
 	err = w.Send(env)
 	if err != nil {
 		t.Fatalf("failed to send second envelope with seed %d: %s.", seed, err)