security-and-privacy/CanvasBlocker
security-and-privacy/CanvasBlocker
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Code Releases Activity

Improved faking performance.

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This commit is contained in:
kkapsner 2016-05-14 19:12:45 +02:00
parent 7a0cad6966
commit 699698f529
1 changed files with 22 additions and 9 deletions
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31
lib/modifiedAPI.js
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@ -28,27 +28,40 @@
); );
} }
data = imageData.data; data = imageData.data;
var l = data.length;
var randomI = 65536;
var randomOffset = 0;
var randomNumbers = new Uint8Array(Math.min(65536, l));
for (var i = 0, l = data.length; i < l; i += 1){ for (var i = 0; i < l; i += 1, randomI += 1){
if (randomI >= randomNumbers.length){
randomI = 0;
randomOffset += randomNumbers.length;
if (l - i < 65536){
randomNumbers = new Uint8Array(l - i);
}
window.crypto.getRandomValues(randomNumbers);
}
var rnd = randomNumbers[randomI];
var value = source[i]; var value = source[i];
if (value >= 0x80){ if (value >= 0x80){
value = value ^ Math.floor(Math.random() * 0x20); value = value ^ (rnd & 0x1F);
} }
else if (value >= 0x40){ else if (value >= 0x40){
value = value ^ Math.floor(Math.random() * 0x10); value = value ^ (rnd & 0x0F);
} }
else if (value >= 0x20){ else if (value >= 0x20){
value = value ^ Math.floor(Math.random() * 0x08); value = value ^ (rnd & 0x07);
} }
else if (value >= 0x10){ else if (value >= 0x10){
value = value ^ Math.floor(Math.random() * 0x04); value = value ^ (rnd & 0x03);
} }
else if (value >= 0x08){ else if (value >= 0x08){
value = value ^ Math.floor(Math.random() * 0x02); value = value ^ (rnd & 0x01);
}
else if (value >= 0x04){
value = value ^ Math.floor(Math.random() * 0x01);
} }
// else if (value >= 0x04){
// value = value ^ (rnd * 0x00);
// }
data[i] = value; data[i] = value;
} }
var canvas = original.cloneNode(true); var canvas = original.cloneNode(true);