Please disregard this, I've made a glaring error in the perl script
omitting the -cipher option, no idea what it uses for default.
On Friday, 26 October 2012 11:30:56 UTC+10, Troy wrote:
>
> 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
>
>
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