Test for SM4

[poundscaoying]

I have noticed that the data used to encrypt in an4_test.go must be 16 or 16*n bytes long.And I have a try to use Encryption function here to encrypt some data like "Hello World",but it doesn't work with Decryption function here.So,does it work in GM module in bccsp for sm4 now? Thanks in advanced.

[poundscaoying]

A mistake in writing.It's sm4_test.go .

[nnsgmsone]

You can use the sm4.Newcipher, Let me give you an example：

 func Sm4Encryption(key, iv, plainText []byte) ([]byte, error) {
    block, err := sm4.NewCipher(key)
    if err != nil {
        return nil, err
    }
    blockSize := block.BlockSize()
    origData := PKCS5Padding(plainText, blockSize)
    blockMode := cipher.NewCBCEncrypter(block, iv)
    cryted := make([]byte, len(origData))
    blockMode.CryptBlocks(cryted, origData)
    return cryted, nil
}
func Sm4Decryption(key, iv, cipherText []byte) ([]byte, error) {
    block, err := sm4.NewCipher(key)
    if err != nil {
        return nil, err
    }
    blockMode := cipher.NewCBCDecrypter(block, iv)
    origData := make([]byte, len(cipherText))
    blockMode.CryptBlocks(origData, cipherText)
    origData = PKCS5UnPadding(origData)
    return origData, nil
}
func PKCS5Padding(src []byte, blockSize int) []byte {
    padding := blockSize - len(src)%blockSize
    padtext := bytes.Repeat([]byte{byte(padding)}, padding)
    return append(src, padtext...)
}
func PKCS5UnPadding(src []byte) []byte {
    length := len(src)
    unpadding := int(src[length-1])
    return src[:(length - unpadding)]
}
func main() {
    originalText := "sysys"
    fmt.Println(originalText)
    mytext := []byte(originalText)
    key := []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}
    iv := []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}
    cryptoText, _ := Sm4Encryption(key, iv, mytext)
    fmt.Println(string(cryptoText))
    decryptedText, _ := Sm4Decryption(key, iv, cryptoText)
    fmt.Println(string(decryptedText))
}

[tjfoc]

please leave comments if still have questions/issues. thanks

[poundscaoying]

I got it, thanks a lot.

[nnsgmsone]

It's okay.

[QuincyWuzefeng]

nice

[xgswust]

the sm4-cbc is different form openssl sm4-cbc, why?