Crypt::PK::X25519 - Asymmetric cryptography based on X25519

NAME  SYNOPSIS  DESCRIPTION  METHODS  new  generate_key  import_key  import_key_raw  export_key_der  export_key_pem  export_key_jwk  export_key_raw  shared_secret  is_private  key2hash  SEE ALSO 

NAME

Crypt::PK::X25519 − Asymmetric cryptography based on X25519

SYNOPSIS

use Crypt::PK::X25519;
#Shared secret
my $priv = Crypt::PK::X25519−>new('Alice_priv_x25519.der');
my $pub = Crypt::PK::X25519−>new('Bob_pub_x25519.der');
my $shared_secret = $priv−>shared_secret($pub);
#Load key
my $pk = Crypt::PK::X25519−>new;
my $pk_hex = "EA7806F721A8570512C8F6EFB4E8D620C49A529E4DF5EAA77DEC646FB1E87E41";
$pk−>import_key_raw(pack("H*", $pk_hex), "public");
my $sk = Crypt::PK::X25519−>new;
my $sk_hex = "002F93D10BA5728D8DD8E9527721DABA3261C0BB1BEFDE7B4BBDAC631D454651";
$sk−>import_key_raw(pack("H*", $sk_hex), "private");
#Key generation
my $pk = Crypt::PK::X25519−>new−>generate_key;
my $private_der = $pk−>export_key_der('private');
my $public_der = $pk−>export_key_der('public');
my $private_pem = $pk−>export_key_pem('private');
my $public_pem = $pk−>export_key_pem('public');
my $private_raw = $pk−>export_key_raw('private');
my $public_raw = $pk−>export_key_raw('public');
my $private_jwk = $pk−>export_key_jwk('private');
my $public_jwk = $pk−>export_key_jwk('public');

DESCRIPTION

Since: CryptX−0.067

METHODS

new

my $pk = Crypt::PK::X25519−>new();
#or
my $pk = Crypt::PK::X25519−>new($priv_or_pub_key_filename);
#or
my $pk = Crypt::PK::X25519−>new(\$buffer_containing_priv_or_pub_key);

Support for password protected PEM keys

my $pk = Crypt::PK::X25519−>new($priv_pem_key_filename, $password);
#or
my $pk = Crypt::PK::X25519−>new(\$buffer_containing_priv_pem_key, $password);

generate_key

Uses Yarrow-based cryptographically strong random number generator seeded with random data taken from "/dev/random" (UNIX) or "CryptGenRandom" (Win32).

$pk−>generate_key;

import_key

Loads private or public key in DER or PEM format.

$pk−>import_key($filename);
#or
$pk−>import_key(\$buffer_containing_key);

Support for password protected PEM keys:

$pk−>import_key($filename, $password);
#or
$pk−>import_key(\$buffer_containing_key, $password);

Loading private or public keys form 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://tools.ietf.org/html/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

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

export_key_pem

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

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

Export raw public/private key

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

shared_secret

# 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

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",
}

SEE ALSO

•

<https://en.wikipedia.org/wiki/Curve25519>

•

<https://tools.ietf.org/html/rfc7748>
Updated 2024-01-29 - jenkler.se | uex.se