org.openeuler.sun.security.util.ByteArrays Maven / Gradle / Ivy
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package org.openeuler.sun.security.util;
/**
* A time-instance comparison of two byte arrays.
*/
public class ByteArrays {
// See the MessageDigest.isEqual(byte[] digesta, byte[] digestb)
// implementation. This is a potential enhancement of the
// MessageDigest class.
public static boolean isEqual(byte[] a, int aFromIndex, int aToIndex,
byte[] b, int bFromIndex, int bToIndex) {
if (a == b) {
return true;
}
if (a == null || b == null) {
return false;
}
if (a.length == 0) {
return b.length == 0;
}
int lenA = aToIndex - aFromIndex;
int lenB = bToIndex - bFromIndex;
if (lenB == 0) {
return lenA == 0;
}
int result = 0;
result |= lenA - lenB;
// time-constant comparison
for (int indexA = 0; indexA < lenA; indexA++) {
int indexB = ((indexA - lenB) >>> 31) * indexA;
result |= a[aFromIndex + indexA] ^ b[bFromIndex + indexB];
}
return result == 0;
}
}