package secp256k1 import ( "bytes" "crypto/sha256" "crypto/subtle" "fmt" "io" secp256k1 "github.com/btcsuite/btcd/btcec" amino "github.com/tendermint/go-amino" "github.com/tendermint/tendermint/crypto" "golang.org/x/crypto/ripemd160" ) //------------------------------------- const ( Secp256k1PrivKeyAminoRoute = "tendermint/PrivKeySecp256k1" Secp256k1PubKeyAminoRoute = "tendermint/PubKeySecp256k1" ) var cdc = amino.NewCodec() func init() { cdc.RegisterInterface((*crypto.PubKey)(nil), nil) cdc.RegisterConcrete(PubKeySecp256k1{}, Secp256k1PubKeyAminoRoute, nil) cdc.RegisterInterface((*crypto.PrivKey)(nil), nil) cdc.RegisterConcrete(PrivKeySecp256k1{}, Secp256k1PrivKeyAminoRoute, nil) } //------------------------------------- var _ crypto.PrivKey = PrivKeySecp256k1{} // PrivKeySecp256k1 implements PrivKey. type PrivKeySecp256k1 [32]byte // Bytes marshalls the private key using amino encoding. func (privKey PrivKeySecp256k1) Bytes() []byte { return cdc.MustMarshalBinaryBare(privKey) } // Sign creates an ECDSA signature on curve Secp256k1, using SHA256 on the msg. func (privKey PrivKeySecp256k1) Sign(msg []byte) ([]byte, error) { priv, _ := secp256k1.PrivKeyFromBytes(secp256k1.S256(), privKey[:]) sig, err := priv.Sign(crypto.Sha256(msg)) if err != nil { return nil, err } return sig.Serialize(), nil } // PubKey performs the point-scalar multiplication from the privKey on the // generator point to get the pubkey. func (privKey PrivKeySecp256k1) PubKey() crypto.PubKey { _, pubkeyObject := secp256k1.PrivKeyFromBytes(secp256k1.S256(), privKey[:]) var pubkeyBytes PubKeySecp256k1 copy(pubkeyBytes[:], pubkeyObject.SerializeCompressed()) return pubkeyBytes } // Equals - you probably don't need to use this. // Runs in constant time based on length of the keys. func (privKey PrivKeySecp256k1) Equals(other crypto.PrivKey) bool { if otherSecp, ok := other.(PrivKeySecp256k1); ok { return subtle.ConstantTimeCompare(privKey[:], otherSecp[:]) == 1 } return false } // GenPrivKey generates a new ECDSA private key on curve secp256k1 private key. // It uses OS randomness in conjunction with the current global random seed // in tendermint/libs/common to generate the private key. func GenPrivKey() PrivKeySecp256k1 { return genPrivKey(crypto.CReader()) } // genPrivKey generates a new secp256k1 private key using the provided reader. func genPrivKey(rand io.Reader) PrivKeySecp256k1 { privKeyBytes := [32]byte{} _, err := io.ReadFull(rand, privKeyBytes[:]) if err != nil { panic(err) } // crypto.CRandBytes is guaranteed to be 32 bytes long, so it can be // casted to PrivKeySecp256k1. return PrivKeySecp256k1(privKeyBytes) } // GenPrivKeySecp256k1 hashes the secret with SHA2, and uses // that 32 byte output to create the private key. // NOTE: secret should be the output of a KDF like bcrypt, // if it's derived from user input. func GenPrivKeySecp256k1(secret []byte) PrivKeySecp256k1 { privKey32 := sha256.Sum256(secret) // sha256.Sum256() is guaranteed to be 32 bytes long, so it can be // casted to PrivKeySecp256k1. return PrivKeySecp256k1(privKey32) } //------------------------------------- var _ crypto.PubKey = PubKeySecp256k1{} // PubKeySecp256k1Size is comprised of 32 bytes for one field element // (the x-coordinate), plus one byte for the parity of the y-coordinate. const PubKeySecp256k1Size = 33 // PubKeySecp256k1 implements crypto.PubKey. // It is the compressed form of the pubkey. The first byte depends is a 0x02 byte // if the y-coordinate is the lexicographically largest of the two associated with // the x-coordinate. Otherwise the first byte is a 0x03. // This prefix is followed with the x-coordinate. type PubKeySecp256k1 [PubKeySecp256k1Size]byte // Address returns a Bitcoin style addresses: RIPEMD160(SHA256(pubkey)) func (pubKey PubKeySecp256k1) Address() crypto.Address { hasherSHA256 := sha256.New() hasherSHA256.Write(pubKey[:]) // does not error sha := hasherSHA256.Sum(nil) hasherRIPEMD160 := ripemd160.New() hasherRIPEMD160.Write(sha) // does not error return crypto.Address(hasherRIPEMD160.Sum(nil)) } // Bytes returns the pubkey marshalled with amino encoding. func (pubKey PubKeySecp256k1) Bytes() []byte { bz, err := cdc.MarshalBinaryBare(pubKey) if err != nil { panic(err) } return bz } func (pubKey PubKeySecp256k1) VerifyBytes(msg []byte, sig []byte) bool { pub, err := secp256k1.ParsePubKey(pubKey[:], secp256k1.S256()) if err != nil { return false } parsedSig, err := secp256k1.ParseDERSignature(sig[:], secp256k1.S256()) if err != nil { return false } return parsedSig.Verify(crypto.Sha256(msg), pub) } func (pubKey PubKeySecp256k1) String() string { return fmt.Sprintf("PubKeySecp256k1{%X}", pubKey[:]) } func (pubKey PubKeySecp256k1) Equals(other crypto.PubKey) bool { if otherSecp, ok := other.(PubKeySecp256k1); ok { return bytes.Equal(pubKey[:], otherSecp[:]) } return false }