NSData-AES Class Encryption/Decryption in Cocoa
- by David Schiefer
hi,
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];
