Encryptor Class Reference

Inheritance diagram for Encryptor:

Collaboration diagram for Encryptor:

Instance Methods
(id)	- initWithPassword:
(NSData *)	- encryptData:
(NSData *)	- decryptData:
(NSData *)	- encryptString:
(NSString *)	- decryptString:

Properties
NSString *	plaintextPassword

Detailed Description

Definition at line 27 of file Encryptor.h.

Method Documentation

decryptData:

- (NSData *) decryptData:

(NSData *)

encrypted_data

Definition at line 1 of file Encryptor.m.

                       :(NSData *)encrypted_data
{
  if ([encrypted_data length] <= TSXEncryptorBlockCipherBlockSize)
    return nil;
 
  NSMutableData *plaintext_data =
      [NSMutableData dataWithLength:[encrypted_data length] + TSXEncryptorBlockCipherBlockSize];
  size_t data_out_moved = 0;
 
  int ret =
      CCCrypt(kCCDecrypt, TSXEncryptorBlockCipherAlgo, TSXEncryptorBlockCipherOptions,
              [_encryption_key bytes], TSXEncryptorBlockCipherKeySize, [encrypted_data bytes],
              [encrypted_data bytes] + TSXEncryptorBlockCipherBlockSize,
              [encrypted_data length] - TSXEncryptorBlockCipherBlockSize,
              [plaintext_data mutableBytes], [plaintext_data length], &data_out_moved);
 
  switch (ret)
  {
    case kCCSuccess:
      [plaintext_data setLength:data_out_moved];
      return plaintext_data;
 
    case kCCBufferTooSmall: // Our output buffer is big enough to decrypt valid data. This
                            // return code indicates malformed data.
    case kCCAlignmentError: // Shouldn't get this, since we're using padding.
    case kCCDecodeError:    // Wrong key.
      return nil;
 
    default:
      NSLog(@"%s: uncaught error, ret CCCryptorStatus = %d (encrypted data len = %lu; buffer "
            @"size = %lu; dom = %lu)",
            __func__, ret, (unsigned long)[encrypted_data length],
            (unsigned long)[plaintext_data length], data_out_moved);
      return nil;
  }
 
  return nil;
}

decryptString:

- (NSString *) decryptString:

(NSData *)

encrypted_string

Definition at line 1 of file Encryptor.m.

                           :(NSData *)encrypted_string
{
  return [[[NSString alloc] initWithData:[self decryptData:encrypted_string]
                                encoding:NSUTF8StringEncoding] autorelease];
}

encryptData:

- (NSData *) encryptData:

(NSData *)

plaintext_data

Definition at line 1 of file Encryptor.m.

                       :(NSData *)plaintext_data
{
  if (![plaintext_data length])
    return nil;
 
  NSData *iv = [self randomInitializationVector];
  NSMutableData *encrypted_data = [NSMutableData
      dataWithLength:[iv length] + [plaintext_data length] + TSXEncryptorBlockCipherBlockSize];
  [encrypted_data replaceBytesInRange:NSMakeRange(0, [iv length]) withBytes:[iv bytes]];
 
  size_t data_out_moved = 0;
  int ret = CCCrypt(kCCEncrypt, TSXEncryptorBlockCipherAlgo, TSXEncryptorBlockCipherOptions,
                    [_encryption_key bytes], TSXEncryptorBlockCipherKeySize, [iv bytes],
                    [plaintext_data bytes], [plaintext_data length],
                    [encrypted_data mutableBytes] + [iv length],
                    [encrypted_data length] - [iv length], &data_out_moved);
 
  switch (ret)
  {
    case kCCSuccess:
      [encrypted_data setLength:[iv length] + data_out_moved];
      return encrypted_data;
 
    default:
      NSLog(
          @"%s: uncaught error, ret CCCryptorStatus = %d (plaintext len = %lu; buffer size = "
          @"%lu)",
          __func__, ret, (unsigned long)[plaintext_data length],
          (unsigned long)([encrypted_data length] - [iv length]));
      return nil;
  }
 
  return nil;
}

encryptString:

- (NSData *) encryptString:

(NSString *)

plaintext_string

Definition at line 1 of file Encryptor.m.

                         :(NSString *)plaintext_string
{
  return [self encryptData:[plaintext_string dataUsingEncoding:NSUTF8StringEncoding]];
}

initWithPassword:

- (id) initWithPassword:

(NSString *)

plaintext_password

Definition at line 1 of file Encryptor.m.

                      :(NSString *)plaintext_password
{
  if (plaintext_password == nil)
    return nil;
 
  if (!(self = [super init]))
    return nil;
 
  _plaintext_password = [plaintext_password retain];
  const char *plaintext_password_data =
      [plaintext_password length] ? [plaintext_password UTF8String] : " ";
 
  if (!plaintext_password_data || !strlen(plaintext_password_data))
    [NSException raise:NSInternalInconsistencyException
                format:@"%s: plaintext password data is zero length!", __func__];
 
  uint8_t *derived_key = calloc(1, TSXEncryptorPBKDF2KeySize);
 
  int ret = CCKeyDerivationPBKDF(
      kCCPBKDF2, plaintext_password_data, strlen(plaintext_password_data) - 1,
      (const uint8_t *)TSXEncryptorPBKDF2Salt, TSXEncryptorPBKDF2SaltLen, kCCPRFHmacAlgSHA1,
      TSXEncryptorPBKDF2Rounds, derived_key, TSXEncryptorPBKDF2KeySize);
 
  if (ret)
  {
    NSLog(@"%s: CCKeyDerivationPBKDF ret == %d, indicating some sort of failure.", __func__,
          ret);
    free(derived_key);
    [self autorelease];
    return nil;
  }
 
  _encryption_key = [[NSData alloc] initWithBytesNoCopy:derived_key
                                                 length:TSXEncryptorPBKDF2KeySize
                                           freeWhenDone:YES];
  return self;
}

Property Documentation

plaintextPassword

- (NSString*) plaintextPassword

readatomicassign

Definition at line 34 of file Encryptor.h.

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The documentation for this class was generated from the following files:

• Encryptor.h
• Encryptor.m