c# - 为什么我的解密文本中出现随机字符？

Answer 1

Thanks to Hans Passant I found the solution. The problem was that I was using Encoding.GetString() or Encoding.GetBytes() when I was encrypting and decrypting, when I should have been using Convert.ToBase64String() or Convert.FromBase64String().

Answer 2

I had the same problem of extra output. For me it was not encoding-problem, because I was passing it as byte array in BCrypt library. As it is plain-text, I would use space-character as padding before encryption and trim after decryption.

int padding = BLOCK_SIZE - (input_len+1)%BLOCK_SIZE;
if(padding && (input_len+padding) <= buf_size)
{
   memset(buf+input_len, ' ', padding);
   input_len += padding;
}

For 128 bit encryption, the block-size is 16. Note that the buf_size should be multiple of the block-size to make it work all the time. As we padded the input already, we do not need the padding algorithm in decryption.

tdsAlg.Padding = PaddingMode.None;

And at the end of decryption, I would trim the output.