From e839fa80a30f451ab16054034c24191f2e4c0f38 Mon Sep 17 00:00:00 2001
From: Andreas Fischer <bantu@phpbb.com>
Date: Sun, 13 Apr 2014 00:35:24 +0200
Subject: [PATCH] Add Diffie-Hellman Test to BigInteger Testcase.

---
 tests/Math/BigInteger/TestCase.php | 38 ++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/tests/Math/BigInteger/TestCase.php b/tests/Math/BigInteger/TestCase.php
index ea9d4e2b..78c72b5f 100644
--- a/tests/Math/BigInteger/TestCase.php
+++ b/tests/Math/BigInteger/TestCase.php
@@ -265,4 +265,42 @@ abstract class Math_BigInteger_TestCase extends PhpseclibTestCase
         $this->assertSame('18446744073709551616', (string) $x);
         $this->assertSame('18446744073709551616', (string) $y);
     }
+
+    public function testDiffieHellmanKeyAgreement()
+    {
+        // "Oakley Group 14" 2048-bit modular exponentiation group as used in
+        // SSH2 diffie-hellman-group14-sha1
+        $prime = $this->getInstance(
+            'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1' .
+            '29024E088A67CC74020BBEA63B139B22514A08798E3404DD' .
+            'EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245' .
+            'E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED' .
+            'EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D' .
+            'C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F' .
+            '83655D23DCA3AD961C62F356208552BB9ED529077096966D' .
+            '670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B' .
+            'E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9' .
+            'DE2BCBF6955817183995497CEA956AE515D2261898FA0510' .
+            '15728E5A8AACAA68FFFFFFFFFFFFFFFF',
+            16
+        );
+        $generator = $this->getInstance(2);
+
+        $one = $this->getInstance(1);
+        $max = $one->bitwise_leftShift(512)->subtract($one);
+
+        $alicePrivate = $one->random($one, $max);
+        $alicePublic = $generator->modPow($alicePrivate, $prime);
+
+        $bobPrivate = $one->random($one, $max);
+        $bobPublic =  $generator->modPow($bobPrivate, $prime);
+
+        $aliceShared = $bobPublic->modPow($alicePrivate, $prime);
+        $bobShared = $alicePublic->modPow($bobPrivate, $prime);
+
+        $this->assertTrue(
+            $aliceShared->equals($bobShared),
+            'Failed asserting that Alice and Bob share the same BigInteger.'
+        );
+    }
 }