Crypt::...XChaCha(3)

✨ NAME ✨

okay bestie, welcome to the Crypt::...XChaCha(3) page — yes, a User Contributed Perl Documentation page — and the main character is Crypt::Stream::XChaCha: the stream cipher XChaCha20. 💅

🦋 SYNOPSIS 🦋

use Crypt::Stream::XChaCha;

# encrypt
my $key    = "12345678901234567890123456789012";  # 32 bytes
my $nonce  = "123456789012345678901234";          # 24 bytes
my $enc_stream = Crypt::Stream::XChaCha->new($key, $nonce);
my $ct = $enc_stream->crypt("plain message");

# decrypt
my $dec_stream = Crypt::Stream::XChaCha->new($key, $nonce);
my $pt = $dec_stream->crypt($ct);

🌸 DESCRIPTION 🌸

Since: CryptX-0.089 — noted, bestie. ✨

This gives you an interface to the XChaCha20 stream cipher, which is an extended-nonce variant of ChaCha20 using a 192-bit (24-byte) nonce. Lowkey iconic. 🎀

💅 METHODS 💅

Unless noted otherwise, assume $stream is an existing stream object created via new, for example:

my $stream = Crypt::Stream::XChaCha->new($key, $nonce);

🎀 new 🎀

my $stream = Crypt::Stream::XChaCha->new($key, $nonce);
#or
my $stream = Crypt::Stream::XChaCha->new($key, $nonce, $rounds);

# $key    .. [binary string] 32 bytes
# $nonce  .. [binary string] 24 bytes
# $rounds .. [integer] optional, rounds (DEFAULT: 20)

• $key — [binary string] 32 bytes.
• $nonce — [binary string] 24 bytes.
• $rounds — [integer] optional, rounds (DEFAULT: 20).

🔥 crypt 🔥

Encrypts or decrypts data. The output has the same length as the input. Returns a binary string (raw bytes). 💖

The input is converted using Perl's usual scalar stringification. Passing undef is treated as an empty string with the usual warning, and numeric scalars are stringified before processing.

my $ciphertext = $stream->crypt($plaintext);
#or
my $plaintext = $stream->crypt($ciphertext);

🌟 keystream 🌟

Returns $length bytes of raw keystream as a binary string. 💫

The length is taken using Perl's usual numeric coercion. Values that coerce to an oversized unsigned length are rejected as too large. No sneaky giant lengths, periodt. 🔥

my $random_bytes = $stream->keystream($length);

🦋 clone 🦋

Returns a copy of the stream cipher object in its current state. Snapshot slay. 📸

my $stream2 = $stream->clone;

🌈 SEE ALSO 🌈

• Crypt::Stream::ChaCha, Crypt::Stream::XSalsa20
• <https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-xchacha> — go read the draft, bestie.

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xoxo 💖 this page is perl v5.42.0, dated 2026-05-11, and it's the Crypt::...XChaCha(3) manual. periodt ✨