10-27-2012
Hi fpmurphy. Thanks for the input. You wouldn't by chance know what happens when you calculate your keys from really small prime numbers and then try encrypting data blocks larger than the keys would you? Cause the math is not working out for me. When I calculate it by hand with a calculator program the decrypted data is not the same as what was encrytped.
---------- Post updated at 11:15 AM ---------- Previous update was at 10:17 AM ----------
Nevermind guys, I found the answer to my question. The answer can be summed up in this sentence from a professor at Purdue:
"Since our message integer M must be smaller than the modulus n, obviously our
block size cannot equal the modulus size."
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LEARN ABOUT CENTOS
crypt::des
DES(3) User Contributed Perl Documentation DES(3)
NAME
Crypt::DES - Perl DES encryption module
SYNOPSIS
use Crypt::DES;
DESCRIPTION
The module implements the Crypt::CBC interface, which has the following methods
blocksize =item keysize =item encrypt =item decrypt
FUNCTIONS
blocksize
Returns the size (in bytes) of the block cipher.
keysize
Returns the size (in bytes) of the key. Optimal size is 8 bytes.
new
my $cipher = new Crypt::DES $key;
This creates a new Crypt::DES BlockCipher object, using $key, where $key is a key of "keysize()" bytes.
encrypt
my $cipher = new Crypt::DES $key;
my $ciphertext = $cipher->encrypt($plaintext);
This function encrypts $plaintext and returns the $ciphertext where $plaintext and $ciphertext should be of "blocksize()" bytes.
decrypt
my $cipher = new Crypt::DES $key;
my $plaintext = $cipher->decrypt($ciphertext);
This function decrypts $ciphertext and returns the $plaintext where $plaintext and $ciphertext should be of "blocksize()" bytes.
EXAMPLE
my $key = pack("H16", "0123456789ABCDEF");
my $cipher = new Crypt::DES $key;
my $ciphertext = $cipher->encrypt("plaintex"); # NB - 8 bytes
print unpack("H16", $ciphertext), "
";
NOTES
Do note that DES only uses 8 byte keys and only works on 8 byte data blocks. If you're intending to encrypt larger blocks or entire files,
please use Crypt::CBC in conjunction with this module. See the Crypt::CBC documentation for proper syntax and use.
Also note that the DES algorithm is, by today's standard, weak encryption. Crypt::Blowfish is highly recommended if you're interested in
using strong encryption and a faster algorithm.
SEE ALSO
Crypt::Blowfish Crypt::IDEA
Bruce Schneier, Applied Cryptography, 1995, Second Edition, published by John Wiley & Sons, Inc.
COPYRIGHT
The implementation of the DES algorithm was developed by, and is copyright of, Eric Young (eay@mincom.oz.au). Other parts of the perl
extension and module are copyright of Systemics Ltd ( http://www.systemics.com/ ). Cross-platform work and packaging for single algorithm
distribution is copyright of W3Works, LLC.
MAINTAINER
This single-algorithm package and cross-platform code is maintained by Dave Paris <amused@pobox.com>.
perl v5.16.3 2005-12-08 DES(3)