diff --git a/src/main/java/helpers/ScryptHelper.java b/src/main/java/helpers/ScryptHelper.java
index 99a7906..418087d 100644
--- a/src/main/java/helpers/ScryptHelper.java
+++ b/src/main/java/helpers/ScryptHelper.java
@@ -107,7 +107,7 @@
 					return false;
 				}
 			}
-			
+
 			boolean result = MessageDigest.isEqual(cHash, hash);
 
 			Arrays.fill(salt, (byte) 0);
@@ -136,13 +136,11 @@
 		}
 	}
 
-	private static int log2(int operand) {
-		double log2 = Math.log(operand) / Math.log(2);
-		if (log2 % 1 != 0) {
-			throw new IllegalArgumentException("N must be a power of 2.");
-		} else {
-			return Math.toIntExact(Math.round(log2));
+	private static int log2(int n) {
+		if (n <= 0 || (n & (n - 1)) != 0) {
+			throw new IllegalArgumentException("N must be a power of 2");
 		}
+		return Integer.numberOfTrailingZeros(n);
 	}
 
 	/*