session-ios/SignalServiceKit/src/Util/NSData+OWSConstantTimeCompare.m
Michael Kirk ccb4a88742 Import SSK (and history) into Signal-iOS
git remote add ssk ../SignalServiceKit
git remote update
git merge -s ours --allow-unrelated-histories --no-commit ssk/master
git read-tree --prefix=SignalServiceKit -u ssk/master
git commit
2017-07-21 13:55:01 -04:00

33 lines
746 B
Objective-C

//
// Copyright (c) 2017 Open Whisper Systems. All rights reserved.
//
#import "NSData+OWSConstantTimeCompare.h"
NS_ASSUME_NONNULL_BEGIN
@implementation NSData (OWSConstantTimeCompare)
- (BOOL)ows_constantTimeIsEqualToData:(NSData *)other
{
BOOL isEqual = YES;
if (self.length != other.length) {
return NO;
}
UInt8 *leftBytes = (UInt8 *)self.bytes;
UInt8 *rightBytes = (UInt8 *)other.bytes;
for (int i = 0; i < self.length; i++) {
// rather than returning as soon as we find a discrepency, we compare the rest of
// the byte stream to maintain a constant time comparison
isEqual = isEqual && (leftBytes[i] == rightBytes[i]);
}
return isEqual;
}
@end
NS_ASSUME_NONNULL_END