path: root/include/bls/bls.hpp

#pragma once
/**
    @file
    @brief BLS threshold signature on BN curve
    @author MITSUNARI Shigeo(@herumi)
    @license modified new BSD license
    http://opensource.org/licenses/BSD-3-Clause
*/
#ifndef BLS_FP_UNIT_SIZE
    #error "define BLS_FP_UNIT_SIZE 4(or 6)"
#endif
#include <vector>
#include <string>
#include <iosfwd>
#include <stdint.h>

#ifdef _MSC_VER
    #pragma comment(lib, "mcl.lib")
    #pragma comment(lib, "bls.lib")
#endif

namespace bls {

enum {
    CurveFp254BNb = 0,
    CurveFp382_1 = 1,
    CurveFp382_2 = 2
};

// same value with IoMode of mcl/op.hpp
enum {
    IoBin = 2, // binary number
    IoDec = 10, // decimal number
    IoHex = 16, // hexadecimal number
    IoFixedByteSeq = 512 // fixed byte representation
};

namespace impl {

struct SecretKey;
struct PublicKey;
struct Signature;
struct Id;

} // bls::impl

/*
    BLS signature
    e : G2 x G1 -> Fp12
    Q in G2 ; fixed global parameter
    H : {str} -> G1
    s : secret key
    sQ ; public key
    s H(m) ; signature of m
    verify ; e(sQ, H(m)) = e(Q, s H(m))
*/

/*
    initialize this library
    call this once before using the other method
    @param curve [in] type of curve
    @param maxUnitSize [in] 4 or 6 (specify same value used in compiling for validation)
    @note init() is not thread safe
*/
void init(int curve = CurveFp254BNb, int maxUnitSize = BLS_FP_UNIT_SIZE);
size_t getOpUnitSize();
void getCurveOrder(std::string& str);
void getFieldOrder(std::string& str);

class SecretKey;
class PublicKey;
class Signature;
class Id;

/*
    the value of secretKey and Id must be less than
    r = 0x2523648240000001ba344d8000000007ff9f800000000010a10000000000000d
    sizeof(uint64_t) * keySize byte
*/
const size_t keySize = BLS_FP_UNIT_SIZE;

typedef std::vector<SecretKey> SecretKeyVec;
typedef std::vector<PublicKey> PublicKeyVec;
typedef std::vector<Signature> SignatureVec;
typedef std::vector<Id> IdVec;

class Id {
    uint64_t self_[BLS_FP_UNIT_SIZE];
    friend class PublicKey;
    friend class SecretKey;
    template<class T, class G> friend struct WrapArray;
    impl::Id& getInner() { return *reinterpret_cast<impl::Id*>(self_); }
    const impl::Id& getInner() const { return *reinterpret_cast<const impl::Id*>(self_); }
public:
    Id(unsigned int id = 0);
    bool operator==(const Id& rhs) const;
    bool operator!=(const Id& rhs) const { return !(*this == rhs); }
    friend std::ostream& operator<<(std::ostream& os, const Id& id);
    friend std::istream& operator>>(std::istream& is, Id& id);
    void getStr(std::string& str, int ioMode = 0) const;
    void setStr(const std::string& str, int ioMode = 0);
    bool isZero() const;
    /*
        set p[0, .., keySize)
        @note the value must be less than r
    */
    void set(const uint64_t *p);
    // bufSize is truncted/zero extended to keySize
    void setLittleEndian(const void *buf, size_t bufSize);
};

/*
    s ; secret key
*/
class SecretKey {
    uint64_t self_[BLS_FP_UNIT_SIZE];
    template<class T, class G> friend struct WrapArray;
    impl::SecretKey& getInner() { return *reinterpret_cast<impl::SecretKey*>(self_); }
    const impl::SecretKey& getInner() const { return *reinterpret_cast<const impl::SecretKey*>(self_); }
public:
    SecretKey() : self_() {}
    bool operator==(const SecretKey& rhs) const;
    bool operator!=(const SecretKey& rhs) const { return !(*this == rhs); }
    friend std::ostream& operator<<(std::ostream& os, const SecretKey& sec);
    friend std::istream& operator>>(std::istream& is, SecretKey& sec);
    void getStr(std::string& str, int ioMode = 0) const;
    void setStr(const std::string& str, int ioMode = 0);
    /*
        initialize secretKey with random number and set id = 0
    */
    void init();
    /*
        set secretKey with p[0, .., keySize) and set id = 0
        @note the value must be less than r
    */
    void set(const uint64_t *p);
    // bufSize is truncted/zero extended to keySize
    void setLittleEndian(const void *buf, size_t bufSize);
    // set hash of buf
    void setHashOf(const void *buf, size_t bufSize);
    void getPublicKey(PublicKey& pub) const;
    // constant time sign
    void sign(Signature& sig, const std::string& m) const;
    /*
        make Pop(Proof of Possesion)
        pop = prv.sign(pub)
    */
    void getPop(Signature& pop) const;
    /*
        make [s_0, ..., s_{k-1}] to prepare k-out-of-n secret sharing
    */
    void getMasterSecretKey(SecretKeyVec& msk, size_t k) const;
    /*
        set a secret key for id > 0 from msk
    */
    void set(const SecretKeyVec& msk, const Id& id)
    {
        set(msk.data(), msk.size(), id);
    }
    /*
        recover secretKey from k secVec
    */
    void recover(const SecretKeyVec& secVec, const IdVec& idVec);
    /*
        add secret key
    */
    void add(const SecretKey& rhs);

    // the following methods are for C api
    /*
        the size of msk must be k
    */
    void set(const SecretKey *msk, size_t k, const Id& id);
    void recover(const SecretKey *secVec, const Id *idVec, size_t n);
};

/*
    sQ ; public key
*/
class PublicKey {
    uint64_t self_[BLS_FP_UNIT_SIZE * 2 * 3];
    friend class SecretKey;
    friend class Signature;
    template<class T, class G> friend struct WrapArray;
    impl::PublicKey& getInner() { return *reinterpret_cast<impl::PublicKey*>(self_); }
    const impl::PublicKey& getInner() const { return *reinterpret_cast<const impl::PublicKey*>(self_); }
public:
    PublicKey() : self_() {}
    bool operator==(const PublicKey& rhs) const;
    bool operator!=(const PublicKey& rhs) const { return !(*this == rhs); }
    friend std::ostream& operator<<(std::ostream& os, const PublicKey& pub);
    friend std::istream& operator>>(std::istream& is, PublicKey& pub);
    void getStr(std::string& str, int ioMode = 0) const;
    void setStr(const std::string& str, int ioMode = 0);
    /*
        set public for id from mpk
    */
    void set(const PublicKeyVec& mpk, const Id& id)
    {
        set(mpk.data(), mpk.size(), id);
    }
    /*
        recover publicKey from k pubVec
    */
    void recover(const PublicKeyVec& pubVec, const IdVec& idVec);
    /*
        add public key
    */
    void add(const PublicKey& rhs);

    // the following methods are for C api
    void set(const PublicKey *mpk, size_t k, const Id& id);
    void recover(const PublicKey *pubVec, const Id *idVec, size_t n);
};

/*
    s H(m) ; signature
*/
class Signature {
    uint64_t self_[BLS_FP_UNIT_SIZE * 3];
    friend class SecretKey;
    template<class T, class G> friend struct WrapArray;
    impl::Signature& getInner() { return *reinterpret_cast<impl::Signature*>(self_); }
    const impl::Signature& getInner() const { return *reinterpret_cast<const impl::Signature*>(self_); }
public:
    Signature() : self_() {}
    bool operator==(const Signature& rhs) const;
    bool operator!=(const Signature& rhs) const { return !(*this == rhs); }
    friend std::ostream& operator<<(std::ostream& os, const Signature& s);
    friend std::istream& operator>>(std::istream& is, Signature& s);
    void getStr(std::string& str, int ioMode = 0) const;
    void setStr(const std::string& str, int ioMode = 0);
    bool verify(const PublicKey& pub, const std::string& m) const;
    /*
        verify self(pop) with pub
    */
    bool verify(const PublicKey& pub) const;
    /*
        recover sig from k sigVec
    */
    void recover(const SignatureVec& sigVec, const IdVec& idVec);
    /*
        add signature
    */
    void add(const Signature& rhs);

    // the following methods are for C api
    void recover(const Signature* sigVec, const Id *idVec, size_t n);
};

/*
    make master public key [s_0 Q, ..., s_{k-1} Q] from msk
*/
inline void getMasterPublicKey(PublicKeyVec& mpk, const SecretKeyVec& msk)
{
    const size_t n = msk.size();
    mpk.resize(n);
    for (size_t i = 0; i < n; i++) {
        msk[i].getPublicKey(mpk[i]);
    }
}

/*
    make pop from msk and mpk
*/
inline void getPopVec(SignatureVec& popVec, const SecretKeyVec& msk)
{
    const size_t n = msk.size();
    popVec.resize(n);
    for (size_t i = 0; i < n; i++) {
        msk[i].getPop(popVec[i]);
    }
}

inline Signature operator+(const Signature& a, const Signature& b) { Signature r(a); r.add(b); return r; }
inline PublicKey operator+(const PublicKey& a, const PublicKey& b) { PublicKey r(a); r.add(b); return r; }
inline SecretKey operator+(const SecretKey& a, const SecretKey& b) { SecretKey r(a); r.add(b); return r; }

} //bls