package ethsecp256k1 import ( "bytes" "crypto/ecdsa" "crypto/subtle" "fmt" ethcrypto "github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/crypto/secp256k1" "github.com/cosmos/cosmos-sdk/codec" cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types" sdkerrors "github.com/cosmos/cosmos-sdk/types/errors" tmcrypto "github.com/tendermint/tendermint/crypto" ) const ( // PrivKeySize defines the size of the PrivKey bytes PrivKeySize = 32 // PubKeySize defines the size of the PubKey bytes PubKeySize = 33 // KeyType is the string constant for the Secp256k1 algorithm KeyType = "eth_secp256k1" ) // Amino encoding names const ( // PrivKeyName defines the amino encoding name for the EthSecp256k1 private key PrivKeyName = "ethermint/PrivKeyEthSecp256k1" // PubKeyName defines the amino encoding name for the EthSecp256k1 public key PubKeyName = "ethermint/PubKeyEthSecp256k1" ) // ---------------------------------------------------------------------------- // secp256k1 Private Key var ( _ cryptotypes.PrivKey = &PrivKey{} _ codec.AminoMarshaler = &PrivKey{} ) // GenerateKey generates a new random private key. It returns an error upon // failure. func GenerateKey() (*PrivKey, error) { priv, err := ethcrypto.GenerateKey() if err != nil { return nil, err } return &PrivKey{ Key: ethcrypto.FromECDSA(priv), }, nil } // Bytes returns the byte representation of the ECDSA Private Key. func (privKey PrivKey) Bytes() []byte { return privKey.Key } // PubKey returns the ECDSA private key's public key. func (privKey PrivKey) PubKey() cryptotypes.PubKey { ecdsaPrivKey := privKey.ToECDSA() return &PubKey{ Key: ethcrypto.CompressPubkey(&ecdsaPrivKey.PublicKey), } } // Equals returns true if two ECDSA private keys are equal and false otherwise. func (privKey PrivKey) Equals(other cryptotypes.LedgerPrivKey) bool { return privKey.Type() == other.Type() && subtle.ConstantTimeCompare(privKey.Bytes(), other.Bytes()) == 1 } // Type returns eth_secp256k1 func (privKey PrivKey) Type() string { return KeyType } // MarshalAmino overrides Amino binary marshalling. func (privKey PrivKey) MarshalAmino() ([]byte, error) { return privKey.Key, nil } // UnmarshalAmino overrides Amino binary marshalling. func (privKey *PrivKey) UnmarshalAmino(bz []byte) error { if len(bz) != PrivKeySize { return fmt.Errorf("invalid privkey size, expected %d got %d", PrivKeySize, len(bz)) } privKey.Key = bz return nil } // MarshalAminoJSON overrides Amino JSON marshalling. func (privKey PrivKey) MarshalAminoJSON() ([]byte, error) { // When we marshal to Amino JSON, we don't marshal the "key" field itself, // just its contents (i.e. the key bytes). return privKey.MarshalAmino() } // UnmarshalAminoJSON overrides Amino JSON marshalling. func (privKey *PrivKey) UnmarshalAminoJSON(bz []byte) error { return privKey.UnmarshalAmino(bz) } // Sign creates a recoverable ECDSA signature on the secp256k1 curve over the // Keccak256 hash of the provided message. The produced signature is 65 bytes // where the last byte contains the recovery ID. func (privKey PrivKey) Sign(msg []byte) ([]byte, error) { return ethcrypto.Sign(ethcrypto.Keccak256Hash(msg).Bytes(), privKey.ToECDSA()) } // ToECDSA returns the ECDSA private key as a reference to ecdsa.PrivateKey type. // The function will panic if the private key is invalid. func (privKey PrivKey) ToECDSA() *ecdsa.PrivateKey { key, err := ethcrypto.ToECDSA(privKey.Bytes()) if err != nil { panic(err) } return key } // ---------------------------------------------------------------------------- // secp256k1 Public Key var ( _ cryptotypes.PubKey = &PubKey{} _ codec.AminoMarshaler = &PubKey{} ) // Address returns the address of the ECDSA public key. // The function will panic if the public key is invalid. func (pubKey PubKey) Address() tmcrypto.Address { pubk, err := ethcrypto.DecompressPubkey(pubKey.Key) if err != nil { panic(err) } return tmcrypto.Address(ethcrypto.PubkeyToAddress(*pubk).Bytes()) } // Bytes returns the raw bytes of the ECDSA public key. func (pubKey PubKey) Bytes() []byte { return pubKey.Key } // String implements the fmt.Stringer interface. func (pubKey PubKey) String() string { return fmt.Sprintf("EthPubKeySecp256k1{%X}", pubKey.Key) } // Type returns eth_secp256k1 func (pubKey PubKey) Type() string { return KeyType } // Equals returns true if the pubkey type is the same and their bytes are deeply equal. func (pubKey PubKey) Equals(other cryptotypes.PubKey) bool { return pubKey.Type() == other.Type() && bytes.Equal(pubKey.Bytes(), other.Bytes()) } // MarshalAmino overrides Amino binary marshalling. func (pubKey PubKey) MarshalAmino() ([]byte, error) { return pubKey.Key, nil } // UnmarshalAmino overrides Amino binary marshalling. func (pubKey *PubKey) UnmarshalAmino(bz []byte) error { if len(bz) != PubKeySize { return sdkerrors.Wrapf(sdkerrors.ErrInvalidPubKey, "invalid pubkey size, expected %d, got %d", PubKeySize, len(bz)) } pubKey.Key = bz return nil } // MarshalAminoJSON overrides Amino JSON marshalling. func (pubKey PubKey) MarshalAminoJSON() ([]byte, error) { // When we marshal to Amino JSON, we don't marshal the "key" field itself, // just its contents (i.e. the key bytes). return pubKey.MarshalAmino() } // UnmarshalAminoJSON overrides Amino JSON marshalling. func (pubKey *PubKey) UnmarshalAminoJSON(bz []byte) error { return pubKey.UnmarshalAmino(bz) } // VerifySignature verifies that the ECDSA public key created a given signature over // the provided message. It will calculate the Keccak256 hash of the message // prior to verification. func (pubKey PubKey) VerifySignature(msg []byte, sig []byte) bool { if len(sig) == 65 { // remove recovery ID if contained in the signature sig = sig[:len(sig)-1] } // the signature needs to be in [R || S] format when provided to VerifySignature return secp256k1.VerifySignature(pubKey.Key, ethcrypto.Keccak256Hash(msg).Bytes(), sig) }