NSData-AES Class Encryption/Decryption in Cocoa
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Why not use the built-in encryption algorithms? Here's an NSData+AES i wrote which uses CCCrypt with a 256it key for AES256 encryption.
You can use it like:
NSData *data = [[NSData dataWithContentsOfFile:@"/etc/passwd"]
encryptWithString:@"mykey"];
and decrypt it with:
NSData *file = [data decryptWithString:@"mykey"];
DISCLAIMER: There no guarantee my NSData+AES is bug-free :) It's fairly new. I welcome code reviews.
Comments
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Pripyat almost 2 years
I am attempting to encrypt/decrypt a plain text file in my text editor. encrypting seems to work fine, but the decrypting does not work, the text comes up encrypted. I am certain i've decrypted the text using the word i encrypted it with - could someone look through the snippet below and help me out?
Thanks :)
Encrypting:
NSAlert *alert = [NSAlert alertWithMessageText:@"Encryption" defaultButton:@"Set" alternateButton:@"Cancel" otherButton:nil informativeTextWithFormat:@"Please enter a password to encrypt your file with:"]; [alert setIcon:[NSImage imageNamed:@"License.png"]]; NSSecureTextField *input = [[NSSecureTextField alloc] initWithFrame:NSMakeRect(0, 0, 300, 24)]; [alert setAccessoryView:input]; NSInteger button = [alert runModal]; if (button == NSAlertDefaultReturn) { [[NSUserDefaults standardUserDefaults] setObject:[input stringValue] forKey:@"password"]; NSData *data; [self setString:[textView textStorage]]; NSMutableDictionary *dict = [NSDictionary dictionaryWithObject:NSPlainTextDocumentType forKey:NSDocumentTypeDocumentAttribute]; [textView breakUndoCoalescing]; data = [[self string] dataFromRange:NSMakeRange(0, [[self string] length]) documentAttributes:dict error:outError]; NSData*encrypt = [data AESEncryptWithPassphrase:[input stringValue]]; [encrypt writeToFile:[absoluteURL path] atomically:YES];
Decrypting:
NSAlert *alert = [NSAlert alertWithMessageText:@"Decryption" defaultButton:@"Open" alternateButton:@"Cancel" otherButton:nil informativeTextWithFormat:@"This file has been protected with a password.To view its contents,enter the password below:"]; [alert setIcon:[NSImage imageNamed:@"License.png"]]; NSSecureTextField *input = [[NSSecureTextField alloc] initWithFrame:NSMakeRect(0, 0, 300, 24)]; [alert setAccessoryView:input]; NSInteger button = [alert runModal]; if (button == NSAlertDefaultReturn) { NSLog(@"Entered Password - attempting to decrypt."); NSMutableDictionary *dict = [NSDictionary dictionaryWithObject:NSPlainTextDocumentType forKey:NSDocumentTypeDocumentOption]; NSData*decrypted = [[NSData dataWithContentsOfFile:[self fileName]] AESDecryptWithPassphrase:[input stringValue]]; mString = [[NSAttributedString alloc] initWithData:decrypted options:dict documentAttributes:NULL error:outError];