Am Donnerstag, 30. Juni 2016 08:57:11 UTC+2 schrieb Lazytiger:
>
> Hi, all
>
> I have a C# code to decrypt data as following
>
> public static string test(string input, string key)
> {
> if (((input == null) || string.IsNullOrEmpty(input.Trim()))
> || ((input == "false") || (input == "null")))
> {
> return string.Empty;
> }
> RijndaelManaged managed = new RijndaelManaged {
> KeySize = 0x100,
> BlockSize = 0x100,
> Mode = CipherMode.CBC,
> Padding = PaddingMode.PKCS7,
> Key = Encoding.ASCII.GetBytes(key),
> IV = Encoding.ASCII.GetBytes(key)
> };
> try
> {
> byte[] buffer = Convert.FromBase64String(input);
> ICryptoTransform transform = managed.CreateDecryptor();
> byte[] bytes = null;
> using (MemoryStream stream = new MemoryStream())
> {
> using (CryptoStream stream2 = new CryptoStream(stream,
> transform, CryptoStreamMode.Write))
> {
> stream2.Write(buffer, 0, buffer.Length);
> }
> bytes = stream.ToArray();
> }
> return Encoding.ASCII.GetString(bytes);
> }
> catch (Exception exception)
> {
> Console.Write (exception.ToString ());
> return string.Empty;
> }
> }
>
> And I have write a golang code as following:
>
> *func* test1(data, key string) {
> raw, err := base64.StdEncoding.DecodeString(data)
> *if* err != nil {
> *println*(err.Error())
> *return*
> }
>
> block, err := aes.NewCipher([]byte(key))
> *if* err != nil {
> *println*(err.Error())
> *return*
> }
> mode := cipher.NewCBCDecrypter(block, []byte(key)[:aes.BlockSize])
> mode.CryptBlocks(raw, raw)
>
> *println*(string(raw))
> }
>
> Besides the PKCS7 padding problem, I can’t get the right answer. Can
> someone help me with this? Where do I get this IV parameter?
> I Can’t set IV as C# does, because golang just complains about block size
> problem.
>
You geht the IV parameter e.g. from the beginning of the ciphertext
[suggested by go examples 0].
But be careful the IV have to be unique to ensure a safe en- and
decyrption.
I also have modified your example a little bit so that it is working [1]. I
have ignored the error checking, the checking of the block size and the
encoding of the crypted data. Nevertheless I hope it will help you.
[0] https://golang.org/pkg/crypto/cipher/#example_NewCBCDecrypter
[1] https://play.golang.org/p/wEQ9vQIdJS
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
