NAME

Crypt::Stream::XSalsa20 - Stream cipher XSalsa20

SYNOPSIS

use Crypt::Stream::XSalsa20;
# encrypt
my $key    = "12345678901234567890123456789012";  # 32 bytes
my $nonce  = "123456789012345678901234";          # 24 bytes
my $enc_stream = Crypt::Stream::XSalsa20->new($key, $nonce);
my $ct = $enc_stream->crypt("plain message");
# decrypt
my $dec_stream = Crypt::Stream::XSalsa20->new($key, $nonce);
my $pt = $dec_stream->crypt($ct);

DESCRIPTION

Since: CryptX-0.089

Provides an interface to the XSalsa20 stream cipher, an extended-nonce variant of Salsa20 with a 192-bit (24-byte) nonce. The larger nonce makes random nonce generation safe in practice.

METHODS

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

my $stream = Crypt::Stream::XSalsa20->new($key, $nonce);

new

my $stream = Crypt::Stream::XSalsa20->new($key, $nonce);
#or
my $stream = Crypt::Stream::XSalsa20->new($key, $nonce, $rounds);
# $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.

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

clone

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

my $stream2 = $stream->clone;