feat: add tool rsa

tool/rsa.go

@@ -0,0 +1,186 @@
+package tool
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"fmt"
+)
+
+// 通用RSA加密方法（支持选择填充方式）
+func rsaEncrypt(data []byte, publicKey *rsa.PublicKey, useOAEP bool) ([]byte, error) {
+	if len(data) == 0 {
+		return nil, errors.New("input data is empty")
+	}
+
+	if useOAEP {
+		// 使用OAEP填充（更安全）
+		hash := sha256.New()
+		return rsa.EncryptOAEP(hash, rand.Reader, publicKey, data, nil)
+	} else {
+		// 使用PKCS1v15填充（兼容旧系统）
+		return rsa.EncryptPKCS1v15(rand.Reader, publicKey, data)
+	}
+}
+
+// 方法1：通过tls.Config加密
+func RSAEncrypt(data []byte, cfg *tls.Config) (string, error) {
+	// 验证参数
+	if len(data) == 0 {
+		return "", errors.New("input data is empty")
+	}
+	if cfg == nil {
+		return "", errors.New("TLS config is nil")
+	}
+
+	// 获取第一个证书
+	if len(cfg.Certificates) == 0 {
+		return "", errors.New("no certificates found in TLS config")
+	}
+	cert := cfg.Certificates[0]
+
+	// 获取RSA公钥
+	rsaPublicKey, ok := cert.Leaf.PublicKey.(*rsa.PublicKey)
+	if !ok {
+		return "", errors.New("certificate does not contain RSA public key")
+	}
+
+	// 加密（无分块，适用于小数据）
+	encrypted, err := rsaEncrypt(data, rsaPublicKey, true)
+	if err != nil {
+		return "", fmt.Errorf("encryption failed: %w", err)
+	}
+
+	return base64.StdEncoding.EncodeToString(encrypted), nil
+}
+
+// 方法2：通过证书PEM加密（支持分块）
+func RSAEncryptByCert(data, cert []byte) (string, error) {
+	// 解析PEM证书
+	block, _ := pem.Decode(cert)
+	if block == nil || block.Type != "CERTIFICATE" {
+		return "", errors.New("failed to parse certificate PEM")
+	}
+
+	// 解析X.509证书
+	crt, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		return "", fmt.Errorf("failed to parse certificate: %w", err)
+	}
+
+	// 获取RSA公钥
+	publicKey, ok := crt.PublicKey.(*rsa.PublicKey)
+	if !ok {
+		return "", errors.New("certificate does not contain RSA public key")
+	}
+
+	// 计算最大分块大小
+	keySize := publicKey.Size()
+	maxChunk := 0
+
+	maxChunk = keySize - 42 // OAEP填充
+
+	// 不需要分块的情况
+	if len(data) <= maxChunk {
+		encrypted, err := rsaEncrypt(data, publicKey, true)
+		if err != nil {
+			return "", err
+		}
+		return base64.StdEncoding.EncodeToString(encrypted), nil
+	}
+
+	// 需要分块的情况
+	var encrypted []byte
+	for i := 0; i < len(data); i += maxChunk {
+		end := i + maxChunk
+		if end > len(data) {
+			end = len(data)
+		}
+
+		chunk, err := rsaEncrypt(data[i:end], publicKey, true)
+		if err != nil {
+			return "", fmt.Errorf("RSA encryption failed: %w", err)
+		}
+		encrypted = append(encrypted, chunk...)
+	}
+
+	return base64.StdEncoding.EncodeToString(encrypted), nil
+}
+
+func rsaDecryptBlock(block []byte, privateKey *rsa.PrivateKey, useOAEP bool) ([]byte, error) {
+	if useOAEP {
+		// Use OAEP with SHA-256
+		return rsa.DecryptOAEP(
+			sha256.New(),
+			rand.Reader,
+			privateKey,
+			block,
+			nil,
+		)
+	} else {
+		// Use PKCS1v15 for backward compatibility
+		return rsa.DecryptPKCS1v15(
+			rand.Reader,
+			privateKey,
+			block,
+		)
+	}
+}
+
+func RSADecrypt(encryptedBase64 string, cfg *tls.Config) ([]byte, error) {
+	// Validate inputs
+	if encryptedBase64 == "" {
+		return nil, errors.New("encrypted data is empty")
+	}
+	if cfg == nil {
+		return nil, errors.New("TLS config is nil")
+	}
+	if len(cfg.Certificates) == 0 {
+		return nil, errors.New("no certificates found in TLS config")
+	}
+
+	// Decode base64 string
+	encryptedData, err := base64.StdEncoding.DecodeString(encryptedBase64)
+	if err != nil {
+		return nil, fmt.Errorf("base64 decoding failed: %w", err)
+	}
+
+	// Get private key from first certificate
+	privateKey, ok := cfg.Certificates[0].PrivateKey.(*rsa.PrivateKey)
+	if !ok {
+		return nil, errors.New("failed to get RSA private key from TLS config")
+	}
+
+	// Determine block size for decryption
+	blockSize := privateKey.Size()
+	if len(encryptedData)%blockSize != 0 {
+		return nil, fmt.Errorf("invalid encrypted data size. Expected multiple of %d, got %d",
+			blockSize, len(encryptedData))
+	}
+
+	// Handle single block decryption
+	if len(encryptedData) == blockSize {
+		return rsaDecryptBlock(encryptedData, privateKey, true)
+	}
+
+	// Handle multi-block decryption
+	var decrypted []byte
+	for i := 0; i < len(encryptedData); i += blockSize {
+		end := i + blockSize
+		block := encryptedData[i:end]
+
+		decryptedBlock, err := rsaDecryptBlock(block, privateKey, true)
+		if err != nil {
+			return nil, fmt.Errorf("block decryption failed at offset %d: %w", i, err)
+		}
+
+		decrypted = append(decrypted, decryptedBlock...)
+	}
+
+	return decrypted, nil
+}