(PHP Extension) Generate ECDSA Key and Get Details as XML

Demonstrates how to generate an ECC key and gets the parts as XML.

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

//  This requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

$ecc = new CkEcc();

//  Generate a random ECC private key on the secp256k1 curve.
//  Chilkat also supports other curves, such as secp384r1, secp521r1, and secp256r1.

//  Create a Fortuna PRNG and seed it with system entropy.
//  This will be our source of random data for generating the ECC private key.
$fortuna = new CkPrng();
$entropy = $fortuna->getEntropy(32,'base64');
$success = $fortuna->AddEntropy($entropy,'base64');

// privKey is a CkPrivateKey
$privKey = $ecc->GenEccKey('secp256k1',$fortuna);
if ($ecc->get_LastMethodSuccess() != true) {
    print $ecc->lastErrorText() . "\n";
    exit;
}

//  An EC private key has this ASN.1
//  ECPrivateKey ::= SEQUENCE {
//      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
//      privateKey     OCTET STRING,
//      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
//      publicKey  [1] BIT STRING OPTIONAL (This is the ANSI X9.63 public key format.)

$asn = new CkAsn();
$success = $asn->LoadEncoded($privKey->getPkcs1ENC('base64'),'base64');
if ($success != true) {
    print $asn->lastErrorText() . "\n";
    exit;
}

$xml = new CkXml();
$xml->LoadXml($asn->asnToXml());

print $xml->getXml() . "\n";

//  The XML looks like this:
//  <?xml version="1.0" encoding="utf-8" ?>
//  <sequence>
//      <int>01</int>
//      <octets>JgJvBG+3wletkJab8iXAkpz0O8/AgWZSpkYVcB7SpnU=</octets>
//      <contextSpecific tag="0" constructed="1">
//          <oid>1.3.132.0.10</oid>
//      </contextSpecific>
//  </sequence>

//  The 32-byte private key is in the octets..
//  Get it as hex.
$crypt = new CkCrypt2();
$privKeyHex = $crypt->reEncode($xml->getChildContent('octets'),'base64','hex');

print 'EC private key as hex = ' . $privKeyHex . "\n";


?>