Add FastPedersenHash.php

web3p · Jul 5, 2024 · 6ba412a · 6ba412a
1 parent 3cc1117
commit 6ba412a
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diff --git a/src/Crypto/FastPedersenHash.php b/src/Crypto/FastPedersenHash.php
@@ -0,0 +1,52 @@
+<?php
+
+/**
+ * This file is part of starknet.php package.
+ * 
+ * (c) Kuan-Cheng,Lai <[email protected]>
+ * 
+ * @author Peter Lai <[email protected]>
+ * @license MIT
+ */
+
+namespace StarkNet\Crypto;
+
+use StarkNet\Constants;
+use StarkNet\Utils;
+use StarkNet\Crypto\Curve;
+
+class FastPedersenHash {
+ public const LOW_PART_BITS = 248;
+
+ // 2 ** 248 - 1
+ public static function LOW_BITS_MASK()
+ {
+ return Utils::toBn('452312848583266388373324160190187140051835877600158453279131187530910662655');
+ }
+
+ public static function processSingleElement($element, $p1, $p2) {
+ $cmpZero = $element->compare(Constants::ZERO());
+ assert($cmpZero >= 0 && $element->compare(Utils::toBN('0x' . Constants::FIELD_PRIME)) < 0, "Element value is out of range");
+ $highNibble = $element->bitwise_rightShift(self::LOW_PART_BITS)->toHex();
+ $lowPart = $element->bitwise_and(self::LOW_BITS_MASK())->toHex();
+ if ($highNibble === '') {
+ $highNibble = '0';
+ }
+ if ($lowPart === '') {
+ $lowPart = '0';
+ }
+ return $p1->mul($lowPart)->add($p2->mul($highNibble));
+ }
+
+ public static function hash($x, $y) {
+ $xBn = Utils::toBn($x);
+ $yBn = Utils::toBn($y);
+ $points = Curve::constantPoints();
+ $hashShiftPoint = $points[0];
+ $p0 = $points[2];
+ $p1 = $points[2 + self::LOW_PART_BITS];
+ $p2 = $points[2 + Constants::N_ELEMENT_BITS_HASH];
+ $p3 = $points[2 + self::LOW_PART_BITS + Constants::N_ELEMENT_BITS_HASH];
+ return ($hashShiftPoint->add(self::processSingleElement($xBn, $p0, $p1))->add(self::processSingleElement($yBn, $p2, $p3)))->getX();
+ }
+}
diff --git a/test/unit/PedersenHashTest.php b/test/unit/PedersenHashTest.php
@@ -7,7 +7,11 @@
 use Test\TestCase;
 use phpseclib\Math\BigInteger as BigNumber;
 use StarkNet\Crypto\PedersenHash;
+use StarkNet\Crypto\FastPedersenHash;
 
+/**
+ * TODO: more test for pedersen hash
+ */
 class PedersenHashTest extends TestCase
 {
  /**
@@ -23,4 +27,18 @@ public function testHash()
  $result = PedersenHash::hash(['2954020266725389012079514584454222423700048665778967545305932093381394777423', '215307247182100370520050591091822763712463273430149262739280891880522753123']);
  $this->assertEquals('02e77dfc2f710d7b4d70028905487511fb49576ee767575225a36db365250475', $result);
  }
+
+ /**
+ * testHashFast
+ * 
+ * @return void
+ */
+ public function testHashFast()
+ {
+ $result = FastPedersenHash::hash(0, '1859938899453001548362772938057778066833094073841168374380996652312065025102');
+ $this->assertEquals('0687ea8d6d09d2106b3f9d69796bf12c54706f0cdc43b63ee73d4f9bc74b454f', $result->toString(16));
+
+ $result = FastPedersenHash::hash('2954020266725389012079514584454222423700048665778967545305932093381394777423', '215307247182100370520050591091822763712463273430149262739280891880522753123');
+ $this->assertEquals('02e77dfc2f710d7b4d70028905487511fb49576ee767575225a36db365250475', $result->toString(16));
+ }
 }