new¶

 my $source = Crypt::PK::X25519->new();
 $source->generate_key;
 my $public_der = $source->export_key_der('public');
 my $pub = Crypt::PK::X25519->new(\$public_der);
 my $private_pem = $source->export_key_pem('private', 'secret', 'AES-256-CBC');
 my $priv = Crypt::PK::X25519->new(\$private_pem, 'secret');

Passing $filename or "\$buffer" to "new" is equivalent: both forms immediately import the key material into the new object.

generate_key¶

Uses the bundled "chacha20" PRNG via rng_make_prng(). The exact OS entropy source is handled by the underlying LibTomCrypt RNG setup. Returns the object itself (for chaining).

 $pk->generate_key;

import_key¶

Loads private or public key in DER or PEM format.

 my $source = Crypt::PK::X25519->new();
 $source->generate_key;
 my $public_der = $source->export_key_der('public');
 my $pub = Crypt::PK::X25519->new();
 $pub->import_key(\$public_der);
 my $private_pem = $source->export_key_pem('private', 'secret', 'AES-256-CBC');
 my $priv = Crypt::PK::X25519->new();
 $priv->import_key(\$private_pem, 'secret');

The same method also accepts filenames instead of buffers.

Loading private or public keys from a Perl HASH:

 $pk->import_key($hashref);
 # the $hashref is either a key exported via key2hash
 $pk->import_key({
      curve => "x25519",
      pub   => "EA7806F721A8570512C8F6EFB4E8D620C49A529E4DF5EAA77DEC646FB1E87E41",
      priv  => "002F93D10BA5728D8DD8E9527721DABA3261C0BB1BEFDE7B4BBDAC631D454651",
 });
 # or a hash with items corresponding to JWK (JSON Web Key)
 $pk->import_key({
       kty => "OKP",
       crv => "X25519",
       d   => "AC-T0Qulco2N2OlSdyHaujJhwLsb7957S72sYx1FRlE",
       x   => "6ngG9yGoVwUSyPbvtOjWIMSaUp5N9eqnfexkb7HofkE",
 });

Supported key formats:

 # all formats can be loaded from a file
 my $pk = Crypt::PK::X25519->new($filename);
 # or from a buffer containing the key
 my $pk = Crypt::PK::X25519->new(\$buffer_with_key);

• X25519 private keys in PEM format

   -----BEGIN X25519 PRIVATE KEY-----
   MC4CAQAwBQYDK2VuBCIEIAAvk9ELpXKNjdjpUnch2royYcC7G+/ee0u9rGMdRUZR
   -----END X25519 PRIVATE KEY-----
      

• X25519 private keys in password protected PEM format

   -----BEGIN X25519 PRIVATE KEY-----
   Proc-Type: 4,ENCRYPTED
   DEK-Info: DES-CBC,DEEFD3D6B714E75A
   dfFWP5bKn49aZ993NVAhQQPdFWgsTb4j8CWhRjGBVTPl6ITstAL17deBIRBwZb7h
   pAyIka81Kfs=
   -----END X25519 PRIVATE KEY-----
      

• X25519 public keys in PEM format

   -----BEGIN PUBLIC KEY-----
   MCowBQYDK2VuAyEA6ngG9yGoVwUSyPbvtOjWIMSaUp5N9eqnfexkb7HofkE=
   -----END PUBLIC KEY-----
      

• PKCS#8 private keys

   -----BEGIN PRIVATE KEY-----
   MC4CAQAwBQYDK2VuBCIEIAAvk9ELpXKNjdjpUnch2royYcC7G+/ee0u9rGMdRUZR
   -----END PRIVATE KEY-----
      

• PKCS#8 encrypted private keys

   -----BEGIN ENCRYPTED PRIVATE KEY-----
   MIGHMEsGCSqGSIb3DQEFDTA+MCkGCSqGSIb3DQEFDDAcBAiS0NOFZmjJswICCAAw
   DAYIKoZIhvcNAgkFADARBgUrDgMCBwQIGd40Hdso8Y4EONSRCTrqvftl9hl3zbH9
   2QmHF1KJ4HDMdLDRxD7EynonCw2SV7BO+XNRHzw2yONqiTybfte7nk9t
   -----END ENCRYPTED PRIVATE KEY-----
      

• X25519 private keys in JSON Web Key (JWK) format

  See <https://www.rfc-editor.org/rfc/rfc8037>

   {
    "kty":"OKP",
    "crv":"X25519",
    "x":"6ngG9yGoVwUSyPbvtOjWIMSaUp5N9eqnfexkb7HofkE",
    "d":"AC-T0Qulco2N2OlSdyHaujJhwLsb7957S72sYx1FRlE",
   }
      

  BEWARE: For JWK support you need to have JSON module installed.

• X25519 public keys in JSON Web Key (JWK) format

   {
    "kty":"OKP",
    "crv":"X25519",
    "x":"6ngG9yGoVwUSyPbvtOjWIMSaUp5N9eqnfexkb7HofkE",
   }
      

  BEWARE: For JWK support you need to have JSON module installed.

import_key_raw¶

Import raw public/private key - can load raw key data exported by "export_key_raw".

 $pk->import_key_raw($key, 'public');
 $pk->import_key_raw($key, 'private');

export_key_der¶

Returns the key as a binary DER-encoded string.

 my $private_der = $pk->export_key_der('private');
 #or
 my $public_der = $pk->export_key_der('public');

export_key_pem¶

Returns the key as a PEM-encoded string (ASCII).

 my $private_pem = $pk->export_key_pem('private');
 #or
 my $public_pem = $pk->export_key_pem('public');

Support for password protected PEM keys

 my $private_pem = $pk->export_key_pem('private', $password);
 #or
 my $private_pem = $pk->export_key_pem('private', $password, $cipher);
 # supported ciphers: 'DES-CBC'
 #                    'DES-EDE3-CBC'
 #                    'SEED-CBC'
 #                    'CAMELLIA-128-CBC'
 #                    'CAMELLIA-192-CBC'
 #                    'CAMELLIA-256-CBC'
 #                    'AES-128-CBC'
 #                    'AES-192-CBC'
 #                    'AES-256-CBC' (DEFAULT)

export_key_jwk¶

Returns a JSON string, or a hashref if the optional second argument is true.

Exports public/private keys as a JSON Web Key (JWK).

 my $private_json_text = $pk->export_key_jwk('private');
 #or
 my $public_json_text = $pk->export_key_jwk('public');

Also exports public/private keys as a Perl HASH with JWK structure.

 my $jwk_hash = $pk->export_key_jwk('private', 1);
 #or
 my $jwk_hash = $pk->export_key_jwk('public', 1);

BEWARE: For JWK support you need to have JSON module installed.

export_key_raw¶

Returns the raw key as a binary string.

Export raw public/private key

 my $private_bytes = $pk->export_key_raw('private');
 #or
 my $public_bytes = $pk->export_key_raw('public');

shared_secret¶

Returns the shared secret as a binary string (raw bytes).

  # Alice having her priv key $pk and Bob's public key $pkb
  my $pk  = Crypt::PK::X25519->new($priv_key_filename);
  my $pkb = Crypt::PK::X25519->new($pub_key_filename);
  my $shared_secret = $pk->shared_secret($pkb);
  # Bob having his priv key $pk and Alice's public key $pka
  my $pk = Crypt::PK::X25519->new($priv_key_filename);
  my $pka = Crypt::PK::X25519->new($pub_key_filename);
  my $shared_secret = $pk->shared_secret($pka);  # same value as computed by Alice

is_private¶

 my $rv = $pk->is_private;
 # 1 .. private key loaded
 # 0 .. public key loaded
 # undef .. no key loaded

key2hash¶

Returns a hashref with the key components, or "undef" if no key is loaded.

 my $hash = $pk->key2hash;
 # returns hash like this (or undef if no key loaded):
 {
   curve => "x25519",
   # raw public key as a hexadecimal string
   pub   => "EA7806F721A8570512C8F6EFB4E8D620C49A529E4DF5EAA77DEC646FB1E87E41",
   # raw private key as a hexadecimal string. undef if key is public only
   priv  => "002F93D10BA5728D8DD8E9527721DABA3261C0BB1BEFDE7B4BBDAC631D454651",
 }