cranberry

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package utility
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import (
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	"crypto/ecdsa"
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	"crypto/elliptic"
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	"crypto/rand"
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	"crypto/sha256"
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	"crypto/x509"
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	"log"
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	"math/big"
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	pbapi "gitverse.ru/IvanTimofeev/cranberry/pkg/grpc"
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)
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func NewSignature(r, s big.Int) *pbapi.Signature {
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	return &pbapi.Signature{
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		R: r.Bytes(),
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		S: s.Bytes(),
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	}
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}
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func GenerateKeys() (*ecdsa.PrivateKey, error) {
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	return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
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}
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func SignTx(priv *ecdsa.PrivateKey, tx *pbapi.Tx) (*pbapi.Signature, error) {
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	hashBytes := TxToHashBytes(tx)
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	r, s, err := ecdsa.Sign(rand.Reader, priv, hashBytes)
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	if err != nil {
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		return nil, err
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	}
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	return NewSignature(*r, *s), nil
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}
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func SignBlock(priv *ecdsa.PrivateKey, bh *pbapi.BlockHeader) (*pbapi.Signature, error) {
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	hashBytes := BlockHeaderToHashBytes(bh)
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	r, s, err := ecdsa.Sign(rand.Reader, priv, hashBytes)
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	if err != nil {
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		return nil, err
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	}
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	return NewSignature(*r, *s), nil
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}
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func VerifyBlock(pub *ecdsa.PublicKey, signature *pbapi.Signature, bh *pbapi.BlockHeader) bool {
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	r := new(big.Int).SetBytes(signature.R)
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	s := new(big.Int).SetBytes(signature.S)
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	hashBytes := BlockHeaderToHashBytes(bh)
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	return ecdsa.Verify(pub, hashBytes, r, s)
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}
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func VerifyTx(pub *ecdsa.PublicKey, txc *pbapi.TxContainer) bool {
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	r := new(big.Int).SetBytes(txc.Signature.R)
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	s := new(big.Int).SetBytes(txc.Signature.S)
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	hashBytes := TxToHashBytes(txc.Tx)
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	return ecdsa.Verify(pub, hashBytes, r, s)
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}
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func BytesToPubKey(data []byte) *ecdsa.PublicKey {
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	pubKey, err := x509.ParsePKIXPublicKey(data)
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	if err != nil {
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		log.Fatalf("Ошибка при парсинге публичного ключа: %v", err)
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	}
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	ecdsaPubKey, ok := pubKey.(*ecdsa.PublicKey)
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	if !ok {
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		log.Fatal("Публичный ключ не является ECDSA публичным ключом")
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	}
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	return ecdsaPubKey
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}
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func PubKeyToBytes(pubKey *ecdsa.PublicKey) []byte {
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	pubKeyBytes, err := x509.MarshalPKIXPublicKey(pubKey)
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	if err != nil {
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		log.Fatalf("Ошибка при сериализации публичного ключа: %v", err)
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	}
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	return pubKeyBytes
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}
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func GeneratePrivKeyBySeed(seed string) (*ecdsa.PrivateKey, error) {
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	hash := sha256.Sum256([]byte(seed))
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	privateKeyInt := new(big.Int).SetBytes(hash[:])
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	curve := elliptic.P256()
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	privateKey := new(ecdsa.PrivateKey)
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	privateKey.D = privateKeyInt
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	privateKey.PublicKey.Curve = curve
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	privateKey.PublicKey.X, privateKey.PublicKey.Y = curve.ScalarBaseMult(privateKey.D.Bytes())
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	return privateKey, nil
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}
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