diff --git a/lib/modifiedAPI.js b/lib/modifiedAPI.js
index 68729e3..a9ca4b0 100644
--- a/lib/modifiedAPI.js
+++ b/lib/modifiedAPI.js
@@ -127,15 +127,25 @@
 		var data2 = imageData2.data;
 		var l = data1.length;
 		if (l === data2.length){
-			var rng = randomSupply.getValueRng(l, window);
+			var rng = randomSupply.getPixelRng(l, window, {});
 			
-			for (var i = 0; i < l; i += 1){
-				if (data1[i] > data2[i]){
-					data2[i] = data1[i] - rng(data1[i] - data2[i], i);
-				}
-				else if (data1[i] < data2[i]){
-					data2[i] = data1[i] + rng(data2[i] - data1[i], i);
-				}
+			for (var i = 0; i < l; i += 4){
+				const signR = data1[i + 0] > data2[i + 0]? -1: 1;
+				const signG = data1[i + 1] > data2[i + 1]? -1: 1;
+				const signB = data1[i + 2] > data2[i + 2]? -1: 1;
+				const signA = data1[i + 3] > data2[i + 3]? -1: 1;
+				
+				var [deltaR, deltaG, deltaB, deltaA] = rng(
+					signR * (data2[i + 0] - data1[i + 0]),
+					signG * (data2[i + 1] - data1[i + 1]),
+					signB * (data2[i + 2] - data1[i + 2]),
+					signA * (data2[i + 3] - data1[i + 3]),
+					i / 4
+				);
+				data2[i + 0] = data1[i + 0] + signR * deltaR;
+				data2[i + 1] = data1[i + 1] + signG * deltaG;
+				data2[i + 2] = data1[i + 2] + signB * deltaB;
+				data2[i + 3] = data1[i + 3] + signA * deltaA;
 			}
 		}
 		return imageData2;
diff --git a/releaseNotes.txt b/releaseNotes.txt
index 8f57282..04c2144 100644
--- a/releaseNotes.txt
+++ b/releaseNotes.txt
@@ -10,7 +10,7 @@ Version 0.5.6:
 		- added setting "protected canvas part" to decouple block mode from part
 	
 	fixes:
-		- 
+		- constant rng did not work properly when protecting input
 	
 	known issues:
 		- if a data URL is blocked the page action button does not appear