package keys import ( "crypto/ecdsa" "crypto/elliptic" "crypto/rand" "crypto/sha256" "crypto/x509" "encoding/hex" "fmt" "math/big" "github.com/nspcc-dev/rfc6979" ) // PrivateKey represents a NEO private key. type PrivateKey struct { b []byte } // NewPrivateKey creates a new random private key. func NewPrivateKey() (*PrivateKey, error) { priv, _, _, err := elliptic.GenerateKey(elliptic.P256(), rand.Reader) if err != nil { return nil, err } return &PrivateKey{b: priv}, nil } // NewPrivateKeyFromHex returns a PrivateKey created from the // given hex string. func NewPrivateKeyFromHex(str string) (*PrivateKey, error) { b, err := hex.DecodeString(str) if err != nil { return nil, err } return NewPrivateKeyFromBytes(b) } // NewPrivateKeyFromBytes returns a NEO PrivateKey from the given byte slice. func NewPrivateKeyFromBytes(b []byte) (*PrivateKey, error) { if len(b) != 32 { return nil, fmt.Errorf( "invalid byte length: expected %d bytes got %d", 32, len(b), ) } return &PrivateKey{b}, nil } // NewPrivateKeyFromASN1 returns a NEO PrivateKey from the ASN.1 serialized key. func NewPrivateKeyFromASN1(b []byte) (*PrivateKey, error) { privkey, err := x509.ParseECPrivateKey(b) if err != nil { return nil, err } return NewPrivateKeyFromBytes(privkey.D.Bytes()) } // PublicKey derives the public key from the private key. func (p *PrivateKey) PublicKey() *PublicKey { var ( c = elliptic.P256() q = new(big.Int).SetBytes(p.b) ) x, y := c.ScalarBaseMult(q.Bytes()) return &PublicKey{X: x, Y: y} } // NewPrivateKeyFromWIF returns a NEO PrivateKey from the given // WIF (wallet import format). func NewPrivateKeyFromWIF(wif string) (*PrivateKey, error) { w, err := WIFDecode(wif, WIFVersion) if err != nil { return nil, err } return w.PrivateKey, nil } // WIF returns the (wallet import format) of the PrivateKey. // Good documentation about this process can be found here: // https://en.bitcoin.it/wiki/Wallet_import_format func (p *PrivateKey) WIF() string { w, err := WIFEncode(p.b, WIFVersion, true) // The only way WIFEncode() can fail is if we're to give it a key of // wrong size, but we have a proper key here, aren't we? if err != nil { panic(err) } return w } // Address derives the public NEO address that is coupled with the private key, and // returns it as a string. func (p *PrivateKey) Address() string { pk := p.PublicKey() return pk.Address() } // Signature creates the signature using the private key. func (p *PrivateKey) Signature() []byte { pk := p.PublicKey() return pk.Signature() } // Sign signs arbitrary length data using the private key. func (p *PrivateKey) Sign(data []byte) []byte { var ( privateKey = p.ecdsa() digest = sha256.Sum256(data) ) r, s := rfc6979.SignECDSA(privateKey, digest[:], sha256.New) params := privateKey.Curve.Params() curveOrderByteSize := params.P.BitLen() / 8 rBytes, sBytes := r.Bytes(), s.Bytes() signature := make([]byte, curveOrderByteSize*2) copy(signature[curveOrderByteSize-len(rBytes):], rBytes) copy(signature[curveOrderByteSize*2-len(sBytes):], sBytes) return signature } // ecsda converts the key to a usable ecsda.PrivateKey for signing data. func (p *PrivateKey) ecdsa() *ecdsa.PrivateKey { priv := new(ecdsa.PrivateKey) priv.PublicKey.Curve = elliptic.P256() priv.D = new(big.Int).SetBytes(p.b) priv.PublicKey.X, priv.PublicKey.Y = priv.PublicKey.Curve.ScalarBaseMult(p.b) return priv } // String implements the stringer interface. func (p *PrivateKey) String() string { return hex.EncodeToString(p.b) } // Bytes returns the underlying bytes of the PrivateKey. func (p *PrivateKey) Bytes() []byte { return p.b }