> Hello,

> I have been trying to figure out how to get decrypting of text in perl
> working in crypto++ (and possibly the reverse).

> #!/usr/bin/perl

> use Crypt::CBC;
> $iv = "12345678";
> $cipher = Crypt::CBC->new( -literal_iv => 1, -literal_key => 1, -key =>
> "wowsers ", -iv => $iv, -header => "none");

> $plaintext = "my message";

> $ciphertext = $cipher->encrypt_hex($plaintext);

> $hex_iv = unpack('H*', $iv);

> print "$hex_iv$ciphertext\n";

> $plaintext = $cipher->decrypt_hex($ciphertext);

> print "$plaintext\n";

> As per the options enabled in perl, I have disabled all of the default
> features and am trying to get it working with a literal key and literal iv
> (which is being prepended to the output.

> I am then failing to decrypt the message using the following crypto++ code:

>     void prepare_key(std::string& key)
>     {
>       ssize_t len = static_cast<ssize_t>(key.length());
>       if (len < Blowfish::MIN_KEYLENGTH)
>         key.append(Blowfish::MIN_KEYLENGTH - len, ' ');
>       else
>       if (len > Blowfish::MAX_KEYLENGTH)
>         key.erase(Blowfish::MIN_KEYLENGTH);
>       else
>       {
>         size_t remainder = len % Blowfish::BLOCKSIZE;
>         if (remainder) key.append(Blowfish::BLOCKSIZE - remainder, ' ');
>       }
>     }

>     bool encrypt(const std::string& source,
>                  std::string& dest,
>                  std::string key)
>     {
>       prepare_key(key);

>       AutoSeededRandomPool prng;
>       byte iv[Blowfish::BLOCKSIZE];
>       prng.GenerateBlock(iv, sizeof(iv));

>       dest.clear();
>       try
>       {
>         CBC_Mode<Blowfish>::Encryption e;
>         e.SetKeyWithIV(reinterpret_cast<const byte*>(key.c_str()),
> key.length(), iv);

>         StringSource(source, true,
>             new StreamTransformationFilter(e,
>                 new StringSink(dest)
>             )
>         );
>       }
>       catch (const Exception& e)
>       {
>         return false;
>       }

>       dest.insert(dest.begin(), std::begin(iv), std::end(iv));

>       return true;
>     }

>     bool decrypt(std::string source, std::string& dest, std::string key)
>     {
>       prepare_key(key);

>       AutoSeededRandomPool prng;
>       byte iv[Blowfish::BLOCKSIZE];
>       std::memcpy(iv, &source[0], sizeof(iv));
>       source.erase(0, sizeof(iv));

>       dest.clear();
>       try
>       {
>         CBC_Mode<Blowfish>::Decryption d;
>         d.SetKeyWithIV(reinterpret_cast<const byte*>(key.c_str()),
> key.length(), iv);

>         StringSource(source, true,
>             new StreamTransformationFilter(d,
>                 new StringSink(dest)
>             )
>         );
>       }
>       catch (const Exception& e)
>       {
>         return false;
>       }

>       return true;
>     }  

> The crypto++ based encrypt / decrypt functions work fine with eachother.
> If I attempt to encrypt the same message as in the perl script with the
> same key and iv, the result is different.

> Any help much appreciated!
> Troy