chore: apply task changes

internal/gateway/crypto.go

@@ -0,0 +1,89 @@
+// Package gateway 提供 Gateway API 加密和签名工具函数
+package gateway
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/md5"
+	"encoding/base64"
+	"encoding/hex"
+	"strconv"
+	"strings"
+
+	"github.com/break/junhong_cmp_fiber/pkg/errors"
+)
+
+const aesBlockSize = 16
+
+// 注意：AES-ECB 存在严重安全缺陷（相同明文块会产生相同密文块），
+// 这是 Gateway 强制要求无法改变，生产环境必须使用 HTTPS 保障传输层安全。
+func aesEncrypt(data []byte, appSecret string) (string, error) {
+	key := md5.Sum([]byte(appSecret))
+	block, err := aes.NewCipher(key[:])
+	if err != nil {
+		return "", errors.Wrap(errors.CodeGatewayEncryptError, err, "数据加密失败")
+	}
+
+	// 使用 PKCS5 进行填充，确保明文长度为 16 的整数倍
+	padded := pkcs5Padding(data, aesBlockSize)
+	encrypted := make([]byte, len(padded))
+	newECBEncrypter(block).CryptBlocks(encrypted, padded)
+	return base64.StdEncoding.EncodeToString(encrypted), nil
+}
+
+// generateSign 生成 Gateway 签名（appId、data、timestamp、key 字母序）
+func generateSign(appID, encryptedData string, timestamp int64, appSecret string) string {
+	var builder strings.Builder
+	builder.WriteString("appId=")
+	builder.WriteString(appID)
+	builder.WriteString("&data=")
+	builder.WriteString(encryptedData)
+	builder.WriteString("&timestamp=")
+	builder.WriteString(strconv.FormatInt(timestamp, 10))
+	builder.WriteString("&key=")
+	builder.WriteString(appSecret)
+
+	sum := md5.Sum([]byte(builder.String()))
+	return strings.ToUpper(hex.EncodeToString(sum[:]))
+}
+
+// ecb 表示 AES-ECB 加密模式的基础结构
+type ecb struct {
+	b         cipher.Block
+	blockSize int
+}
+
+type ecbEncrypter ecb
+
+func newECBEncrypter(b cipher.Block) cipher.BlockMode {
+	if b == nil {
+		panic("crypto/cipher: 传入的加密块为空")
+	}
+	return &ecbEncrypter{b: b, blockSize: b.BlockSize()}
+}
+
+func (x *ecbEncrypter) BlockSize() int {
+	return x.blockSize
+}
+
+func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("crypto/cipher: 输入数据不是完整块")
+	}
+	for len(src) > 0 {
+		x.b.Encrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
+
+// pkcs5Padding 对明文进行 PKCS5 填充
+func pkcs5Padding(data []byte, blockSize int) []byte {
+	padding := blockSize - len(data)%blockSize
+	padded := make([]byte, len(data)+padding)
+	copy(padded, data)
+	for i := len(data); i < len(padded); i++ {
+		padded[i] = byte(padding)
+	}
+	return padded
+}