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Crypt::Stream::Salsa20

Stream cipher Salsa20

   use Crypt::Stream::Salsa20;
   # encrypt
   my $key = "1234567890123456";
   my $nonce  = "12345678";
   my $enc_stream = Crypt::Stream::Salsa20->new($key, $nonce);
   my $ct = $enc_stream->crypt("plain message");
   # decrypt
   my $dec_stream = Crypt::Stream::Salsa20->new($key, $nonce);
   my $pt = $dec_stream->crypt($ct);

Provides an interface to the Salsa20 stream cipher.

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

 my $stream = Crypt::Stream::Salsa20->new($key, $nonce);


 my $stream = Crypt::Stream::Salsa20->new($key, $nonce);
 #or
 my $stream = Crypt::Stream::Salsa20->new($key, $nonce, $counter, $rounds);
 # $key     .. [binary string] 32 or 16 bytes
 # $nonce   .. [binary string] 8 bytes
 # $counter .. [integer] initial counter value (DEFAULT: 0)
 # $rounds  .. [integer] rounds (DEFAULT: 20)

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);

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_key = $stream->keystream($length);

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

 my $stream2 = $stream->clone();

  • Crypt::Stream::ChaCha, Crypt::Stream::RC4, Crypt::Stream::Sober128, Crypt::Stream::Sosemanuk
  • <https://cr.yp.to/snuffle/spec.pdf>