119 lines
3.1 KiB
Go
119 lines
3.1 KiB
Go
package xy_sh
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import (
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"bytes"
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"crypto/cipher"
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"crypto/hmac"
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"crypto/rand"
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"encoding/base64"
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"encoding/hex"
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"fmt"
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"io"
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"time"
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"github.com/tjfoc/gmsm/sm3"
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"github.com/tjfoc/gmsm/sm4"
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)
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// GenerateTimestampMillis 生成毫秒级时间戳字符串
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func GenerateTimestampMillis() string {
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return fmt.Sprintf("%d", time.Now().UnixMilli())
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}
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// SM4Encrypt SM4-CBC模式加密
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// 使用随机IV，IV拼在密文前面，最终输出base64编码字符串
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func SM4Encrypt(plaintext []byte, key []byte) (string, error) {
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if len(key) != 16 {
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return "", fmt.Errorf("SM4密钥长度必须为16字节")
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}
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block, err := sm4.NewCipher(key)
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if err != nil {
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return "", fmt.Errorf("创建SM4 cipher失败: %v", err)
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}
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padded := pkcs7Padding(plaintext, block.BlockSize())
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iv := make([]byte, block.BlockSize())
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if _, err := io.ReadFull(rand.Reader, iv); err != nil {
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return "", fmt.Errorf("生成IV失败: %v", err)
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}
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mode := cipher.NewCBCEncrypter(block, iv)
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ciphertext := make([]byte, len(padded))
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mode.CryptBlocks(ciphertext, padded)
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result := append(iv, ciphertext...)
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return base64.StdEncoding.EncodeToString(result), nil
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}
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// SM4Decrypt SM4-CBC模式解密
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// 输入为base64编码字符串，前16字节为IV，后续为密文
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func SM4Decrypt(encryptedData string, key []byte) ([]byte, error) {
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if len(key) != 16 {
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return nil, fmt.Errorf("SM4密钥长度必须为16字节")
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}
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data, err := base64.StdEncoding.DecodeString(encryptedData)
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if err != nil {
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return nil, fmt.Errorf("base64解码失败: %v", err)
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}
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block, err := sm4.NewCipher(key)
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if err != nil {
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return nil, fmt.Errorf("创建SM4 cipher失败: %v", err)
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}
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blockSize := block.BlockSize()
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if len(data) < blockSize {
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return nil, fmt.Errorf("数据长度不足")
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}
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iv := data[:blockSize]
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ciphertext := data[blockSize:]
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mode := cipher.NewCBCDecrypter(block, iv)
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plaintext := make([]byte, len(ciphertext))
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mode.CryptBlocks(plaintext, ciphertext)
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plaintext, err = pkcs7UnPadding(plaintext)
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if err != nil {
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return nil, fmt.Errorf("去除填充失败: %v", err)
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}
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return plaintext, nil
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}
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// GenerateSign 生成签名
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// 签名规则：将毫秒级时间戳timestamp字符串与encryptedData字符串直接拼接，
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// 使用HMAC-SM3算法结合预先约定的SM3 salt进行加密，输出十六进制字符串
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func GenerateSign(timestamp string, encryptedData string, sm3Salt []byte) string {
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data := timestamp + encryptedData
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mac := hmac.New(sm3.New, sm3Salt)
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mac.Write([]byte(data))
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return hex.EncodeToString(mac.Sum(nil))
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}
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// pkcs7Padding PKCS7填充
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func pkcs7Padding(data []byte, blockSize int) []byte {
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padding := blockSize - len(data)%blockSize
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padText := bytes.Repeat([]byte{byte(padding)}, padding)
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return append(data, padText...)
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}
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// pkcs7UnPadding 去除PKCS7填充
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func pkcs7UnPadding(data []byte) ([]byte, error) {
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length := len(data)
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if length == 0 {
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return nil, fmt.Errorf("数据为空")
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}
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padding := int(data[length-1])
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if padding > length || padding == 0 {
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return nil, fmt.Errorf("无效的填充")
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}
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for i := length - padding; i < length; i++ {
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if data[i] != byte(padding) {
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return nil, fmt.Errorf("无效的填充")
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}
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}
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return data[:length-padding], nil
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} |