IDEA(3)

✨ IDEA — Perl interface to IDEA block cipher ✨

okay bestie so this is IDEA(3), a section-3 manual page for the Perl IDEA module, and it's literally your ticket into the IDEA block cipher from Perl. buckle up, it's a short one and it ate 💅

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🌸 NAME 🌸

IDEA — the Perl interface to the IDEA block cipher. that's it, that's the vibe. no cap.

🦋 SYNOPSIS 🦋

use Crypt::IDEA;

one line. iconic. she's low maintenance.

💖 DESCRIPTION 💖

so this perl extension is an implementation of the IDEA block cipher algorithm. periodt. 💅

the module implements the Crypt::BlockCipher interface, which has the following methods — here's the whole squad:

• blocksize
• keysize
• encrypt
• decrypt

(that's fr fr the list, no extras, no gatekeeping 🫶)

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🎀 FUNCTIONS 🎀

⭐ blocksize

returns the size (in bytes) of the block cipher. that's the input/output chunk size, bestie — memorise it, you'll need it.

⭐ keysize

returns the size (in bytes) of the key. yes, also in bytes. we stay consistent ✨

⭐ new

my $cipher = new IDEA $key;

this creates a new IDEA BlockCipher object, using $key, where $key is a key of keysize() bytes. so like… check your key length first, or it's giving chaos 😭

⭐ encrypt

my $cipher = new IDEA $key;
my $ciphertext = $cipher->encrypt($plaintext);

this function encrypts $plaintext and returns the $ciphertext, where $plaintext and $ciphertext should be of blocksize() bytes. both of them. same size. don't come at me with a 5-byte plaintext 🙈

⭐ decrypt

my $cipher = new IDEA $key;
my $plaintext = $cipher->decrypt($ciphertext);

this function decrypts $ciphertext and returns the $plaintext, where $plaintext and $ciphertext should be of blocksize() bytes. the inverse of the above, obviously — round trip queen 👑

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🌈 EXAMPLE 🌈

okay here's a whole actual working moment:

my $key = pack("H32", "0123456789ABCDEF0123456789ABCDEF");
my $cipher = new IDEA $key;
my $ciphertext = $cipher->encrypt("plaintex");  # NB - 8 bytes
print unpack("H16", $ciphertext), "\n";

and yes bestie, look at that comment — # NB - 8 bytes — "plaintex" is 8 bytes on purpose, because block size. not me noticing you counting on your fingers 💀 it's exactly blocksize() bytes, that's the whole point.

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🔥 SEE ALSO 🔥

• Crypt::CBD
• Crypt::DES
• Crypt::Blowfish

and for the reading list moment 📚 — Bruce Schneier, Applied Cryptography, 1995, Second Edition, published by John Wiley & Sons, Inc. yes it's on the syllabus.

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👑 COPYRIGHT 👑

this implementation is copyright Systemics Ltd ( http://www.systemics.com/ ).

⚠️ also important, bestie: the IDEA algorithm is patented in Europe and the United States by Ascom-Tech AG. not a drill, that's a real legal situation, keep it in mind 🫶

module altered between 1999 and 2005 to allow added functionality with perl -MCPAN, Changes by Dave Paris (edited lib paths, endian issues, new tests).

thank you to contributors for endian patches and new test suite! 🎀 seriously, legends.

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and that's the whole page 🦋 mwah 💋 this one was perl v5.32.1, dated 2019-07-26 — so if you're citing it in the group chat, that's the version and that's the date, iykyk ✨