初始提交：OCI 面板后端（含 GenAI 网关一期）

internal/crypto/aead.go

@@ -0,0 +1,60 @@
+package crypto
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+)
+
+// Cipher 用主密钥派生的 AES-256-GCM 做敏感字段加解密。
+type Cipher struct {
+	aead cipher.AEAD
+}
+
+// NewCipher 以 SHA-256 从主密钥字符串派生 32 字节密钥，
+// 允许 DATA_KEY 是任意长度的强随机字符串。
+func NewCipher(masterKey string) (*Cipher, error) {
+	if masterKey == "" {
+		return nil, fmt.Errorf("new cipher: empty master key")
+	}
+	sum := sha256.Sum256([]byte(masterKey))
+	block, err := aes.NewCipher(sum[:])
+	if err != nil {
+		return nil, fmt.Errorf("new cipher: %w", err)
+	}
+	aead, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("new cipher: %w", err)
+	}
+	return &Cipher{aead: aead}, nil
+}
+
+// EncryptString 加密明文，返回 base64(nonce | ciphertext)。
+func (c *Cipher) EncryptString(plaintext string) (string, error) {
+	nonce := make([]byte, c.aead.NonceSize())
+	if _, err := rand.Read(nonce); err != nil {
+		return "", fmt.Errorf("encrypt: %w", err)
+	}
+	out := c.aead.Seal(nonce, nonce, []byte(plaintext), nil)
+	return base64.StdEncoding.EncodeToString(out), nil
+}
+
+// DecryptString 解密 EncryptString 的输出。
+func (c *Cipher) DecryptString(encoded string) (string, error) {
+	raw, err := base64.StdEncoding.DecodeString(encoded)
+	if err != nil {
+		return "", fmt.Errorf("decrypt: %w", err)
+	}
+	ns := c.aead.NonceSize()
+	if len(raw) < ns {
+		return "", fmt.Errorf("decrypt: ciphertext too short")
+	}
+	plain, err := c.aead.Open(nil, raw[:ns], raw[ns:], nil)
+	if err != nil {
+		return "", fmt.Errorf("decrypt: %w", err)
+	}
+	return string(plain), nil
+}