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JFGuidUtil.m
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JFGuidUtil.m
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//
// JFGuidUtil.m
// JFCommon
//
// Created by Jason Fuerstenberg on 2012/04/02.
// Copyright 2012 Jason Fuerstenberg
//
// http://www.jayfuerstenberg.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#import "JFGuidUtil.h"
@implementation JFGuidUtil
/*
* Returns a GUID with the last section masked with bullet marks (Japanese maru characters).
* If the original GUID is invalid nil is returned.
*
* This method is intended for logging GUIDs which may be sensitive/private in such a way
* that they can be compared with a reasonable degree of certainty by someone in possession
* of both the full GUID and the masked one.
*
* The masked GUID in and of itself cannot help an unauthorized person relearn the original
* GUID as the bulletized portion is lost information.
*/
+ (NSString *) maskedGuidWithOriginalGuid: (NSString *) originalGuid {
NSUInteger length = [originalGuid length];
if (length != 36) {
// The length is not the expected 36 characters so this is an invalid GUID.
return nil;
}
NSRange rangeOfLastHyphen = [originalGuid rangeOfString: @"-"
options: NSBackwardsSearch];
if (rangeOfLastHyphen.location != length - 13) {
// This GUID has no hyphen in front of the last 12 digits, so it is invalid.
return nil;
}
// Replace all the characters after the last hyphen with a maru...
NSUInteger replacementIndex = rangeOfLastHyphen.location + 1;
NSRange replacementRange = NSMakeRange(replacementIndex, length - replacementIndex);
/*
* NOTE: The below bullets may not display as expected if your log is not in UTF8.
* You may change it to any character that suits your purpose though.
*/
NSString *maskedGuid = [originalGuid stringByReplacingCharactersInRange: replacementRange
withString: @"●●●●●●●●●●●●"];
return maskedGuid;
}
@end