支持后台支付配置管理

backend/internal/modules/paymentconfig/encryptor.go

@@ -0,0 +1,102 @@
+package paymentconfig
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"io"
+)
+
+// Encryptor 密钥加密器接口
+type Encryptor interface {
+	Encrypt(plaintext string) (string, error)
+	Decrypt(ciphertext string) (string, error)
+}
+
+// AESEncryptor AES 加密器
+type AESEncryptor struct {
+	key []byte
+}
+
+// NewAESEncryptor 创建 AES 加密器
+// key 必须是 16、24 或 32 字节（对应 AES-128、AES-192、AES-256）
+func NewAESEncryptor(key string) (*AESEncryptor, error) {
+	keyBytes := []byte(key)
+	if len(keyBytes) != 16 && len(keyBytes) != 24 && len(keyBytes) != 32 {
+		return nil, errors.New("invalid key length: must be 16, 24, or 32 bytes")
+	}
+	return &AESEncryptor{key: keyBytes}, nil
+}
+
+// Encrypt 加密明文（使用 AES-GCM）
+func (e *AESEncryptor) Encrypt(plaintext string) (string, error) {
+	if plaintext == "" {
+		return "", nil
+	}
+
+	block, err := aes.NewCipher(e.key)
+	if err != nil {
+		return "", err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", err
+	}
+
+	ciphertext := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
+	return base64.StdEncoding.EncodeToString(ciphertext), nil
+}
+
+// Decrypt 解密密文（使用 AES-GCM）
+func (e *AESEncryptor) Decrypt(ciphertext string) (string, error) {
+	if ciphertext == "" {
+		return "", nil
+	}
+
+	ciphertextBytes, err := base64.StdEncoding.DecodeString(ciphertext)
+	if err != nil {
+		return "", err
+	}
+
+	block, err := aes.NewCipher(e.key)
+	if err != nil {
+		return "", err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+
+	nonceSize := gcm.NonceSize()
+	if len(ciphertextBytes) < nonceSize {
+		return "", errors.New("ciphertext too short")
+	}
+
+	nonce, ciphertextBytes := ciphertextBytes[:nonceSize], ciphertextBytes[nonceSize:]
+	plaintext, err := gcm.Open(nil, nonce, ciphertextBytes, nil)
+	if err != nil {
+		return "", err
+	}
+
+	return string(plaintext), nil
+}
+
+// MockEncryptor 模拟加密器（用于测试）
+type MockEncryptor struct{}
+
+func (e *MockEncryptor) Encrypt(plaintext string) (string, error) {
+	return plaintext, nil
+}
+
+func (e *MockEncryptor) Decrypt(ciphertext string) (string, error) {
+	return ciphertext, nil
+}