path: root/crypto/randentropy/rand_entropy.go

package randentropy

import (
    crand "crypto/rand"
    "github.com/ethereum/go-ethereum/crypto/sha3"
    "io"
)

var Reader io.Reader = &randEntropy{}

type randEntropy struct {
}

func (*randEntropy) Read(bytes []byte) (n int, err error) {
    readBytes := GetEntropyCSPRNG(len(bytes))
    copy(bytes, readBytes)
    return len(bytes), nil
}

// TODO: copied from crypto.go , move to sha3 package?
func Sha3(data []byte) []byte {
    d := sha3.NewKeccak256()
    d.Write(data)

    return d.Sum(nil)
}

func GetEntropyCSPRNG(n int) []byte {
    mainBuff := make([]byte, n)
    _, err := io.ReadFull(crand.Reader, mainBuff)
    if err != nil {
        panic("reading from crypto/rand failed: " + err.Error())
    }
    return mainBuff
}