diff --git a/php/aes_fast.php b/php/aes_fast.php
index 3972a2a..decbe17 100644
--- a/php/aes_fast.php
+++ b/php/aes_fast.php
@@ -429,7 +429,7 @@ private static function main($state,$expandedKey,$nbrRounds){
 	private static function invMain($state, $expandedKey, $nbrRounds){
 			$state = self::addRoundKey($state, self::createRoundKey($expandedKey,16*$nbrRounds));
 			for ($i = $nbrRounds-1; $i > 0; $i--)
-				$state = self::invRound($state, self::createRoundKey($expandedKey,16*i));
+				$state = self::invRound($state, self::createRoundKey($expandedKey,16*$i));
 			$state = self::shiftRows($state,true);
 			$state = self::subBytes($state,true);
 			$state = self::addRoundKey($state, self::createRoundKey($expandedKey,0));
@@ -703,4 +703,4 @@ public static function decrypt($cipherIn,$originalsize,$mode,$key,$size,$iv)
 	 */
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/php/aes_small.php b/php/aes_small.php
index b0c2ef3..bd9e38e 100644
--- a/php/aes_small.php
+++ b/php/aes_small.php
@@ -323,7 +323,7 @@ private static function main($state,$expandedKey,$nbrRounds){
 	private static function invMain($state, $expandedKey, $nbrRounds){
 			$state = self::addRoundKey($state, self::createRoundKey($expandedKey,16*$nbrRounds));
 			for ($i = $nbrRounds-1; $i > 0; $i--)
-				$state = self::invRound($state, self::createRoundKey($expandedKey,16*i));
+				$state = self::invRound($state, self::createRoundKey($expandedKey,16*$i));
 			$state = self::shiftRows($state,true);
 			$state = self::subBytes($state,true);
 			$state = self::addRoundKey($state, self::createRoundKey($expandedKey,0));
@@ -597,4 +597,4 @@ public static function decrypt($cipherIn,$originalsize,$mode,$key,$size,$iv)
 	 */
 }
 
-?>
\ No newline at end of file
+?>