/**
* Generates a secret key and a corresponding public key.
*
* @param mixed 32 byte random string
* @return array private key, public key
*/
public function crypto_sign_keypair($seed = null)
{
if ($seed === null) {
$sk = FieldElement::fromString(Salt::randombytes());
} else {
$sk = Salt::decodeInput($seed);
if ($sk->count() !== Salt::sign_PUBLICKEY) {
throw new SaltException('crypto_sign_keypair: seed must be 32 byte');
}
}
$azDigest = hash('sha512', $sk->toString(), true);
$az = FieldElement::fromString($azDigest);
$az[0] &= 248;
$az[31] &= 63;
$az[31] |= 64;
$ed = Ed25519::instance();
$A = new GeExtended();
$pk = new FieldElement(32);
$ed->geScalarmultBase($A, $az);
$ed->GeExtendedtoBytes($pk, $A);
$sk->setSize(64);
$sk->copy($pk, 32, 32);
return array($sk, $pk);
}
<?php
include "../autoload.php";
$key = Salt::randombytes(32);
$nonce = Salt::randombytes(24);
$msg = 'The Salt::secretbox() function encrypts and authenticates a message using secret key and a nonce.';
$chipertext = Salt::secretbox($msg, $nonce, $key);
$plaintext = Salt::secretbox_open($chipertext, $nonce, $key);
if (!$plaintext) {
echo 'This is a bug';
} else {
echo $plaintext->toString();
}
echo "\n";