Add the encrypt toolkit

utils/encrypt/rc4.go

@@ -0,0 +1,112 @@
+package encrypt
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+)
+
+// RC4Encrypt RC4加密算法结构体
+type RC4Encrypt struct {
+	key []byte
+}
+
+// NewRC4Encrypt 创建新的RC4加密实例
+func NewRC4Encrypt(key []byte) *RC4Encrypt {
+	return &RC4Encrypt{
+		key: key,
+	}
+}
+
+// GenerateRC4Key 生成RC4密钥
+func GenerateRC4Key(length int) ([]byte, error) {
+	if length <= 0 || length > 256 {
+		length = 16 // 默认16字节密钥
+	}
+
+	key := make([]byte, length)
+	_, err := rand.Read(key)
+	if err != nil {
+		return nil, fmt.Errorf("生成RC4密钥失败: %v", err)
+	}
+
+	return key, nil
+}
+
+// rc4KeyScheduling RC4密钥调度算法(KSA)
+func (r *RC4Encrypt) rc4KeyScheduling() []int {
+	s := make([]int, 256)
+
+	// 初始化S盒
+	for i := 0; i < 256; i++ {
+		s[i] = i
+	}
+
+	// 密钥调度
+	j := 0
+	keyLen := len(r.key)
+	for i := 0; i < 256; i++ {
+		j = (j + s[i] + int(r.key[i%keyLen])) % 256
+		s[i], s[j] = s[j], s[i] // 交换
+	}
+
+	return s
+}
+
+// rc4PseudoRandomGeneration RC4伪随机生成算法(PRGA)
+func (r *RC4Encrypt) rc4PseudoRandomGeneration(s []int, data []byte) []byte {
+	result := make([]byte, len(data))
+	i, j := 0, 0
+
+	for k, b := range data {
+		i = (i + 1) % 256
+		j = (j + s[i]) % 256
+		s[i], s[j] = s[j], s[i] // 交换
+
+		keystream := s[(s[i]+s[j])%256]
+		result[k] = b ^ byte(keystream)
+	}
+
+	return result
+}
+
+// Encrypt RC4加密
+func (r *RC4Encrypt) Encrypt(plaintext string) (string, error) {
+	if len(r.key) == 0 {
+		return "", fmt.Errorf("RC4密钥不能为空")
+	}
+
+	data := []byte(plaintext)
+	s := r.rc4KeyScheduling()
+	encrypted := r.rc4PseudoRandomGeneration(s, data)
+
+	// Base64编码
+	return base64.StdEncoding.EncodeToString(encrypted), nil
+}
+
+// Decrypt RC4解密
+func (r *RC4Encrypt) Decrypt(ciphertext string) (string, error) {
+	if len(r.key) == 0 {
+		return "", fmt.Errorf("RC4密钥不能为空")
+	}
+
+	// Base64解码
+	data, err := base64.StdEncoding.DecodeString(ciphertext)
+	if err != nil {
+		return "", fmt.Errorf("Base64解码失败: %v", err)
+	}
+
+	s := r.rc4KeyScheduling()
+	decrypted := r.rc4PseudoRandomGeneration(s, data)
+
+	return string(decrypted), nil
+}
+
+// ParseRC4KeyFromString 从字符串解析RC4密钥
+func ParseRC4KeyFromString(keyStr string) ([]byte, error) {
+	key, err := base64.StdEncoding.DecodeString(keyStr)
+	if err != nil {
+		return nil, fmt.Errorf("解析RC4密钥失败: %v", err)
+	}
+	return key, nil
+}