我需要在加密中实现盐,但要做到这一点,我需要将其存储为我需要创建的文件格式,以便稍后检索它进行解密。在加密方面我是个菜鸟。文件格式规范如下:
密文:密文长度; salt:盐的长度;
然后将密文和盐写出来。这就是 xcode 真正让我困惑的地方,比如创建新文件等。
我该怎么做?然后检索盐进行解密?
谢谢您,非常感谢您的帮助。
最佳答案
您可以考虑使用 NSMutableDictionary
和 NSKeyedUnarchiver
,如下所示:
// Example ciphertext and salt
NSString *ciphertext = @"the ciphertext";
NSString *salt = @"the salt";
// File destination
NSString *path = @"/Users/Anne/Desktop/Archive.dat";
// Create dictionary with ciphertext and salt
NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
[dictionary setObject:ciphertext forKey:@"ciphertext"];
[dictionary setObject:salt forKey:@"salt"];
// Archive dictionary and write to file
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:dictionary];
[data writeToFile:path options:NSDataWritingAtomic error:nil];
// Read file and unarchive
NSMutableDictionary *theDictionary = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
// Get ciphertext and salt
NSString *theCiphertext = [theDictionary objectForKey:@"ciphertext"];
NSString *theSalt = [theDictionary objectForKey:@"salt"];
// Show Result
NSLog(@"Extracted ciphertext: %@",theCiphertext);
NSLog(@"Extracted salt: %@",theSalt);
输出:
Extracted ciphertext: the ciphertext
Extracted salt: the salt
编辑
对评论的回应:NSData
和NSString
都具有长度
。
简单示例:
NSString *theString = @"Example String";
NSData *theData = [theString dataUsingEncoding:NSUTF8StringEncoding];
NSUInteger stringLength = [theString length];
NSUInteger dataLength = [theData length];
NSLog(@"String length: %ld",stringLength);
NSLog(@"Data length: %ld",dataLength);
输出:
String length: 14
Data length: 14
关于cocoa - 实现与加密一起使用的文件格式 - Cocoa,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8073351/