Hi, I'm trying to create a C# Application that encrypts a message with the RijndaelManaged and then decrypt that message with perl, using PasswordDeriveByte to create random IV and Keys, but it seems that Perl reads the Salt but not the IV, so it can generate the key and can't decrypt the message. This is the C# Code : 

The variables are strOrig (PlainText) and strKey (Passphrase)

System.IO.MemoryStream ms = new System.IO.MemoryStream();
            System.Security.Cryptography.RijndaelManaged rj = new Syst
+em.Security.Cryptography.RijndaelManaged();
            rj.Mode = System.Security.Cryptography.CipherMode.CBC;

            RandomNumberGenerator rng = RandomNumberGenerator.Create()
+;
            byte[] salt = new byte[8];
            rng.GetBytes(salt);

            PasswordDeriveBytes pdb = new PasswordDeriveBytes(strKey, 
+salt);
            rj.IV = pdb.GetBytes(16);
            rj.Key = pdb.GetBytes(32);

// Debug so I can see the IV, Key, and Salt Generated
            string strIV = Encoding.UTF8.GetString(rj.IV);
            string _strKey = Encoding.UTF8.GetString(rj.Key);
            string strSalt = Encoding.UTF8.GetString(salt);

            ms.Write(Encoding.UTF8.GetBytes("Salted__"), 0, Encoding.U
+TF8.GetByteCount("Salted__"));
            ms.Write(salt, 0, salt.Length);
            ms.Write(rj.IV, 0, rj.IV.Length);

            byte[] bOrig = Encoding.UTF8.GetBytes(strOrig);

            System.Security.Cryptography.CryptoStream cs = new System.
+Security.Cryptography.CryptoStream(ms, rj.CreateEncryptor(), System.S
+ecurity.Cryptography.CryptoStreamMode.Write);

            cs.Write(bOrig, 0, bOrig.Length);
            cs.FlushFinalBlock();

            string bResult = Convert.ToBase64String(ms.ToArray());
            bResult = bResult.Remove(0, 10);
            ms.Flush();

            return bResult;

[download]
And this is the Perl Code : 
#!/opt/local/bin/perl -w

use IO::Socket;
use IO::Handle;
use MIME::Base64;
use Data::Dumper;
use POSIX;
use Getopt::Long;
use strict;

require Crypt::CBC;

my $msg = "Message_Generated_in_C#";
my $enc_key = "same_as_in_c#_strKey";
my $enc_alg = "Rijndael";

my $cipher = Crypt::CBC->new({
        'key'    => $enc_key,
        'cipher' => $enc_alg,
    });

my $base64_decoded_msg = decode_base64($msg);
my $decrypted_msg = $cipher->decrypt($base64_decoded_msg);

// This is for debug
        print STDERR "    Salt:\n";
        &hex_dump($cipher->salt());
        print STDERR "    Key:\n";
        &hex_dump($cipher->key());
        print STDERR "    IV:\n";
        &hex_dump($cipher->iv());
        print STDERR "    PassPhrase:\n";
        &hex_dump($cipher->passphrase());
        print STDERR "    Block Size: " . $cipher->blocksize() ."\n",
            "    Key Size:   " . $cipher->keysize(). "\n\n";

print "$decrypted_msg\n";


// Function for debug
sub hex_dump() {
    my $data = shift;

    my @chars = split //, $data;
    my $ctr = 0;
    my $ascii_str = '';
    for my $char (@chars) {
        if ($ctr % 16 == 0) {
            print STDERR " $ascii_str\n" if $ascii_str;
            printf STDERR "        0x%.4x:  ", $ctr;
            $ascii_str = '';
        }
        printf STDERR "%.2x", ord($char);

        if ((($ctr+1) % 2 == 0) and ($ctr % 16 != 0)) {
            print STDERR ' ';
        }

        if ($char =~ /[^\x20-\x7e]/) {
            $ascii_str .= '.';
        } else {
            $ascii_str .= $char;
        }
        $ctr++;
    }
    if ($ascii_str) {
        my $remainder = 1;
        if ($ctr % 16 != 0) {
            $remainder = 16 - $ctr % 16;
            if ($remainder % 2 == 0) {
                $remainder = 2*$remainder + int($remainder/2) + 1;
            } else {
                $remainder = 2*$remainder + int($remainder/2) + 2;
            }
        }
        print STDERR ' 'x$remainder, $ascii_str;
    }
    print STDERR "\n";
    return;
}

[download]
I believe that the problem is in the crypting process and the possition of the generated IV key, but I really don't know where to put it.

In reply to Encrypting a Message in C# with Rijndael and Decrypting it on Perl by zeussn

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