diff --git a/phpseclib/Crypt/Hash.php b/phpseclib/Crypt/Hash.php
index feed7896..ab0f488e 100644
--- a/phpseclib/Crypt/Hash.php
+++ b/phpseclib/Crypt/Hash.php
@@ -52,7 +52,7 @@ class Hash
      *
      * @access private
      */
-    //const PADDING_KECCAK = 1;
+    const PADDING_KECCAK = 1;
 
     /**
      * Padding Types
@@ -338,6 +338,8 @@ class Hash
             case 'sha3-224':
                 $this->length = 28;
                 break;
+            case 'keccak256':
+                $this->paddingType = self::PADDING_KECCAK;
             case 'sha256':
             case 'sha512/256':
             case 'sha3-256':
@@ -383,6 +385,7 @@ class Hash
                 break;
             case 'sha3-256':
             case 'shake256':
+            case 'keccak256':
                 $this->blockSize = 1088; // 1600 - 2*256
                 break;
             case 'sha3-384':
@@ -398,10 +401,10 @@ class Hash
                 $this->blockSize = 1024;
         }
 
-        if (in_array(substr($hash, 0, 5), ['sha3-', 'shake'])) {
+        if (in_array(substr($hash, 0, 5), ['sha3-', 'shake', 'kecca'])) {
             // PHP 7.1.0 introduced support for "SHA3 fixed mode algorithms":
             // http://php.net/ChangeLog-7.php#7.1.0
-            if (version_compare(PHP_VERSION, '7.1.0') < 0 || substr($hash, 0,5) == 'shake') {
+            if (version_compare(PHP_VERSION, '7.1.0') < 0 || substr($hash, 0,5) != 'sha3-') {
                 //preg_match('#(\d+)$#', $hash, $matches);
                 //$this->parameters['capacity'] = 2 * $matches[1]; // 1600 - $this->blockSize
                 //$this->parameters['rate'] = 1600 - $this->parameters['capacity']; // == $this->blockSize
@@ -930,10 +933,10 @@ class Hash
     private static function sha3_pad($padLength, $padType)
     {
         switch ($padType) {
-            //case self::PADDING_KECCAK:
-            //    $temp = chr(0x06) . str_repeat("\0", $padLength - 1);
-            //    $temp[$padLength - 1] = $temp[$padLength - 1] | chr(0x80);
-            //    return $temp
+            case self::PADDING_KECCAK:
+                $temp = chr(0x01) . str_repeat("\0", $padLength - 1);
+                $temp[$padLength - 1] = $temp[$padLength - 1] | chr(0x80);
+                return $temp;
             case self::PADDING_SHAKE:
                 $temp = chr(0x1F) . str_repeat("\0", $padLength - 1);
                 $temp[$padLength - 1] = $temp[$padLength - 1] | chr(0x80);
diff --git a/tests/Unit/Crypt/HashTest.php b/tests/Unit/Crypt/HashTest.php
index 80e57f40..84c1b924 100644
--- a/tests/Unit/Crypt/HashTest.php
+++ b/tests/Unit/Crypt/HashTest.php
@@ -144,7 +144,23 @@ class Unit_Crypt_HashTest extends PhpseclibTestCase
                 'shake256-912', // this is what Ed448 uses
                 str_repeat('a', 135), // one character shy of the block size (136)
                 '55b991ece1e567b6e7c2c714444dd201cd51f4f3832d08e1d26bebc63e07a3d7ddeed4a5aa6df7a15f89f2050566f75d9cf1a4dea4ed1f578df0985d5706d49e877d9a913dcdbc26a4c4e807ec72dc10438df95873e24660e39cd49aa4e5df286cb5ba60eaad91ff134754c21cd736681a8f'
-            ]
+            ],
+            // from https://docs.ethers.io/v5/api/utils/hashing/
+            [
+                'keccak256', // used by Ethereum
+                "\x12\x34",
+                '56570de287d73cd1cb6092bb8fdee6173974955fdef345ae579ee9f475ea7432'
+            ],
+            [
+                'keccak256',
+                '',
+                'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470'
+            ],
+            [
+                'keccak256',
+                'hello world',
+                '47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad'
+            ],
         ];
     }
 
@@ -362,7 +378,7 @@ class Unit_Crypt_HashTest extends PhpseclibTestCase
      */
     public function testHash96($hash, $message, $result)
     {
-        if (preg_match('#^sha3-\d+#', $hash) || preg_match('#^shake(?:128|256)-\d+#', $hash)) {
+        if (preg_match('#^sha3-\d+#', $hash) || preg_match('#^shake(?:128|256)-\d+#', $hash) || $hash === 'keccak256') {
             self::markTestSkipped($hash . '-96 not supported');
         }
         $this->assertHashesTo($hash . '-96', $message, substr($result, 0, 24));