feat: add RsaSign and RsaVerifySign

cryptor/crypto.go

@@ -8,16 +8,20 @@ package cryptor
 
 import (
 	"bytes"
+	"crypto"
 	"crypto/aes"
 	"crypto/cipher"
 	"crypto/des"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/sha256"
+	"crypto/sha512"
 	"crypto/x509"
 	"encoding/pem"
+	"errors"
 	"io"
 	"os"
+	"strings"
 )
 
 // AesEcbEncrypt encrypt data with key use AES ECB algorithm
@@ -591,6 +595,7 @@ func RsaEncrypt(data []byte, pubKeyFileName string) []byte {
 	if err != nil {
 		panic(err)
 	}
+
 	return cipherText
 }
 
@@ -624,6 +629,7 @@ func RsaDecrypt(data []byte, privateKeyFileName string) []byte {
 	if err != nil {
 		panic(err)
 	}
+
 	return plainText
 }
 
@@ -655,3 +661,150 @@ func RsaDecryptOAEP(ciphertext []byte, label []byte, key rsa.PrivateKey) ([]byte
 
 	return decryptedBytes, nil
 }
+
+// RsaSign signs the data with RSA.
+// Play: todo
+func RsaSign(hash crypto.Hash, data []byte, privateKeyFileName string) ([]byte, error) {
+	privateKey, err := loadRasPrivateKey(privateKeyFileName)
+	if err != nil {
+		return nil, err
+	}
+
+	hashed, err := hashData(hash, data)
+	if err != nil {
+		return nil, err
+	}
+
+	return rsa.SignPKCS1v15(rand.Reader, privateKey, hash, hashed)
+}
+
+// RsaVerifySign verifies the signature of the data with RSA.
+// Play: todo
+func RsaVerifySign(hash crypto.Hash, data, signature []byte, pubKeyFileName string) error {
+	publicKey, err := loadRsaPublicKey(pubKeyFileName)
+	if err != nil {
+		return err
+	}
+
+	hashed, err := hashData(hash, data)
+	if err != nil {
+		return err
+	}
+
+	return rsa.VerifyPKCS1v15(publicKey, hash, hashed, signature)
+}
+
+// loadRsaPrivateKey loads and parses a PEM encoded private key file.
+func loadRsaPublicKey(filename string) (*rsa.PublicKey, error) {
+	pubKeyData, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	block, _ := pem.Decode(pubKeyData)
+	if block == nil {
+		return nil, errors.New("failed to decode PEM block containing the public key")
+	}
+
+	var pubKey *rsa.PublicKey
+	blockType := strings.ToUpper(block.Type)
+
+	if blockType == "RSA PUBLIC KEY" {
+		pubKey, err = x509.ParsePKCS1PublicKey(block.Bytes)
+		if err != nil {
+			// todo: here should be a bug, should return nil, err
+			key, err := x509.ParsePKIXPublicKey(block.Bytes)
+			if err != nil {
+				return nil, err
+			}
+
+			var ok bool
+			pubKey, ok = key.(*rsa.PublicKey)
+			if !ok {
+				return nil, errors.New("failed to parse RSA private key")
+			}
+		}
+	} else if blockType == "PUBLIC KEY" {
+		key, err := x509.ParsePKIXPublicKey(block.Bytes)
+		if err != nil {
+			return nil, err
+		}
+
+		var ok bool
+		pubKey, ok = key.(*rsa.PublicKey)
+		if !ok {
+			return nil, errors.New("failed to parse RSA private key")
+		}
+
+	} else {
+		return nil, errors.New("unsupported key type")
+	}
+
+	return pubKey, nil
+}
+
+// loadRsaPrivateKey loads and parses a PEM encoded private key file.
+func loadRasPrivateKey(filename string) (*rsa.PrivateKey, error) {
+	priKeyData, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	block, _ := pem.Decode(priKeyData)
+	if block == nil {
+		return nil, errors.New("failed to decode PEM block containing the private key")
+	}
+
+	var privateKey *rsa.PrivateKey
+	blockType := strings.ToUpper(block.Type)
+
+	// PKCS#1 format
+	if blockType == "RSA PRIVATE KEY" {
+		privateKey, err = x509.ParsePKCS1PrivateKey(block.Bytes)
+		if err != nil {
+			return nil, err
+		}
+	} else if blockType == "PRIVATE KEY" { // PKCS#8 format
+		priKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
+		if err != nil {
+			return nil, err
+		}
+		var ok bool
+		privateKey, ok = priKey.(*rsa.PrivateKey)
+		if !ok {
+			return nil, errors.New("failed to parse RSA private key")
+		}
+	} else {
+		return nil, errors.New("unsupported key type")
+	}
+
+	return privateKey, nil
+}
+
+// hashData returns the hash value of the data, using the specified hash function
+func hashData(hash crypto.Hash, data []byte) ([]byte, error) {
+	if !hash.Available() {
+		return nil, errors.New("unsupported hash algorithm")
+	}
+
+	var hashed []byte
+
+	switch hash {
+	case crypto.SHA224:
+		h := sha256.Sum224(data)
+		hashed = h[:]
+	case crypto.SHA256:
+		h := sha256.Sum256(data)
+		hashed = h[:]
+	case crypto.SHA384:
+		h := sha512.Sum384(data)
+		hashed = h[:]
+	case crypto.SHA512:
+		h := sha512.Sum512(data)
+		hashed = h[:]
+	default:
+		return nil, errors.New("unsupported hash algorithm")
+	}
+
+	return hashed, nil
+}