/ 
Crypt-Ed25519-0.1
River stage one • 1 direct dependent • 3 total dependents
/ Crypt::Ed25519

NAME

Crypt::Ed25519 - bare-bones Ed25519 public key signing/verification system

SYNOPSIS

use Crypt::Ed25519; # no symbols exported

# generate a public/private key pair once
($pubkey, $privkey) = Crypt::Ed25519::generate_keypair;

# sign messages
$signature = Crypt::Ed25519::sign $message, $pubkey, $privkey;

# verify message
$valid = Crypt::Ed25519::verify $message, $pubkey, $signature;

# verify, but croak on failure
Crypt::Ed25519::verify_croak $message, $pubkey, $signature;

DESCRIPTION

This module implements Ed25519 public key generation, message signing and verification. It is a pretty bare-bones implementation that implements the standard Ed25519 variant with SHA512 hash, as well as a slower API compatible with the upcoming EdDSA RFC.

The security target for Ed25519 is to be equivalent to 3000 bit RSA or AES-128.

The advantages of Ed25519 over most other signing algorithms are: small public/private key and signature sizes (<= 64 octets), good key generation, signing and verification performance, no reliance on random number generators for signing and by-design immunity against branch or memory access pattern side-channel attacks.

More detailed praise and other info can be found at http://ed25519.cr.yp.to/index.html.

Ed25519 API

($public_key, $private_key) = Crypt::Ed25519::generate_keypair

Creates and returns a new random public and private key pair. The public key is always 32 octets, the private key is always 64 octets long.

$signature = Crypt::Ed25519::sign $message, $public_key, $private_key

Generates a signature for the given message using the public and private keys.

$valid = Crypt::Ed25519::verify $message, $public_key, $signature

Checks whether the $signature is valid for the $message and $public_ke.

Crypt::Ed25519::verify_croak $message, $public_key, $signature

Same as Crypt::Ed25519::verify, but instead of returning a boolean, simply croaks with an error message when the signature isn't valid, so you don't have to think about what the return value really means.

EdDSA compatible API

The upcoming EdDSA draft RFC uses a slightly different (and slower) API for Ed25519. This API is provided by the following functions:

$secret_key = Crypt::Ed25519::eddsa_secret_key

Creates and returns a new secret key, which is always 32 octets long. The secret key can be used to generate the public key via Crypt::Ed25519::eddsa_public_key and is not the same as the private key used in the Ed25519 API.

$public_key = Crypt::Ed25519::eddsa_public_key $secret_key

Takes a secret key generated by Crypt::Ed25519::eddsa_secret_key and returns the corresponding $public_key.

This public key corresponds to the public key in the Ed25519 API above.

$signature = Crypt::Ed25519::eddsa_sign $message, $public_key, $secret_key

Generates a signature for the given message using the public and secret keys.

$valid = Crypt::Ed25519::eddsa_verify $message, $public_key, $signature
Crypt::Ed25519::eddsa_verify_croak $message, $public_key, $signature

Really the same as Crypt::Ed25519::verify and Crypt::Ed25519::verify_croak, i.e. the functions without the eddsa_ prefix. These aliases are provided so it's clear that you are using EdDSA and not Ed25519 API.

CONVERTING BETWEEN Ed25519 and EdDSA

The Ed25519 and EdDSA compatible APIs handle keys slightly differently: The Ed25519 API gives you a public/private key pair, while EdDSA takes a secret and generates a public key from it.

You can convert an EdDSA secret to an Ed25519 private/public key pair using Crypt::Ed25519::generate_keypair:

($public_key, $private_key) = Crypt::Ed25519::generate_keypair $secret

IMPLEMENTATIOIN

This module currently uses "Nightcracker's Ed25519" implementation, but the interface is kept implementation-agnostic to allow usage of other implementations in the future.

AUTHOR

Marc Lehmann <schmorp@schmorp.de>
http://sfotware.schmorp.de/pkg/Crypt-Ed25519.html