NAME

Crypt::MagicSignatures::Key - MagicKeys for the Salmon Protocol

SYNOPSIS

  use Crypt::MagicSignatures::Key;

  my $mkey = Crypt::MagicSignatures::Key->new('RSA.mVgY...');

  my $sig = $mkey->sign('This is a message');

  if ($mkey->verify('This is a message', $sig)) {
    print 'The signature is valid for ' . $mkey->to_string;
  };

DESCRIPTION

Crypt::MagicSignatures::Key implements MagicKeys as described in the MagicSignatures Specification to sign messages of the Salmon Protocol. MagicSignatures is a "robust mechanism for digitally signing nearly arbitrary messages". See Crypt::MagicSignatures::Envelope for using MagicKeys to sign MagicEnvelopes.

ATTRIBUTES

n

  print $mkey->n;
  $mkey->n('456789...');

The MagicKey modulus.

e

  print $mkey->e;
  $mkey->e(3);

The MagicKey public exponent. Defaults to 65537.

d

  print $mkey->d;
  $mkey->d('234567...');

The MagicKey private exponent.

size

  print $mkey->size;

The MagicKey keysize in bits.

METHODS

new

  my $mkey = Crypt::MagicSignatures::Key->new(<<'MKEY');
    RSA.
    mVgY8RN6URBTstndvmUUPb4UZTdwvw
    mddSKE5z_jvKUEK6yk1u3rrC9yN8k6
    FilGj9K0eeUPe2hf4Pj-5CmHww==.
    AQAB.
    Lgy_yL3hsLBngkFdDw1Jy9TmSRMiH6
    yihYetQ8jy-jZXdsZXd8V5ub3kuBHH
    k4M39i3TduIkcrjcsiWQb77D8Q==
  MKEY

  $mkey = Crypt::MagicSignatures::Key->new(
    n => '13145688881420345...',
    d => '87637925876135637...',
    e => 3
  );

The Constructor accepts MagicKeys in compact notation or by attributes.

generate

  my $mkey = Crypt::MagicSignatures::Key->generate(size => 1024);

Generate a new key. Requires Math::Prime::Util to be installed.

Accepts the attributes size and e. In case no size attribute is given, the default key size for generation is 512 bits, which is also the minimum size. The maximum size is 4096 bits. Random prime trials are limited to 100 rounds.

sign

  my $sig = $mkey->sign('This is a message');

Signs a message and returns the signature. The key needs to be a private key. The signature algorithm is based on RFC3447.

verify

  my $sig = $priv_key->sign('This is a message');

  # Successfully verify signature
  if ($pub_key->verify('This is a message', $sig)) {
    print 'The signature is okay.';
  }

  # Fail to verify signature
  else {
    print 'The signature is wrong!';
  };

Verifies a signature of a message based on the public component of the key. Returns a true value on success and false otherwise.

to_string

  my $pub_key = $mkey->to_string;
  my $priv_key = $mkey->to_string(1);

Returns the public key as a string in compact notation. If a true value is passed to the method, the full key (including the private exponent if existing) is returned.

FUNCTIONS

b64url_encode

  use Crypt::MagicSignatures::Key qw/b64url_encode/;

  print b64url_encode('This is a message');
  print b64url_encode('This is a message', 0);

Encodes a string as base-64 with URL safe characters. A second parameter indicates, if trailing equal signs are wanted. The default is true. This differs from MIME::Base64::encode_base64. The function can be exported.

b64url_decode

  use Crypt::MagicSignatures::Key qw/b64url_decode/;

  print b64url_decode('VGhpcyBpcyBhIG1lc3NhZ2U=');

Decodes a base-64 string with URL safe characters. Characters not part of the character set are silently ignored. The function can be exported.

DEPENDENCIES

For signing and verification there are no dependencies other than Perl v5.10.1 and core modules. For key generation Math::Prime::Util v0.21 is necessary.

Either Math::BigInt::GMP (preferred) or Math::BigInt::Pari is strongly recommended for speed improvement (signing and verification) as well as Math::Prime::Util::GMP and Math::Random::ISAAC::XS (key generation).

KNOWN BUGS AND LIMITATIONS

The signing and verification is not guaranteed to be compatible with other implementations, as the specification changed over time!

SEE ALSO

Crypt::MagicSignatures::Envelope, Crypt::RSA::DataFormat, Alt::Crypt::RSA::BigInt, https://github.com/sivy/Salmon.

AVAILABILITY

  https://github.com/Akron/Crypt-MagicSignatures-Key

COPYRIGHT AND LICENSE

Copyright (C) 2012-2018, Nils Diewald.

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.

cpanm Crypt::MagicSignatures::Key

perl -MCPAN -e shell
install Crypt::MagicSignatures::Key