ObjFW  Diff

/*
 * Copyright (c) 2008-2021 Jonathan Schleifer <js@nil.im>
 * Copyright (c) 2008-2022 Jonathan Schleifer <js@nil.im>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#import "OFHMAC.h"
#import "OFSecureData.h"

#import "OFHashAlreadyCalculatedException.h"
#import "OFHashNotCalculatedException.h"
#import "OFInvalidArgumentException.h"

@implementation OFHMAC
@synthesize hashClass = _hashClass;
@synthesize allowsSwappableMemory = _allowsSwappableMemory;

+ (instancetype)HMACWithHashClass: (Class <OFCryptographicHash>)class

	@try {
		if (length > blockSize) {
			id <OFCryptographicHash> hash = [_hashClass
			    hashWithAllowsSwappableMemory:
			    _allowsSwappableMemory];
			[hash updateWithBuffer: key length: length];
			[hash calculate];

			length = hash.digestSize;
			if OF_UNLIKELY (length > blockSize)
				length = blockSize;

			memcpy(outerKeyPadItems, hash.digest, length);
			memcpy(innerKeyPadItems, hash.digest, length);

	if (_calculated)
		@throw [OFHashAlreadyCalculatedException
		    exceptionWithObject: self];

	[_innerHash updateWithBuffer: buffer length: length];
}

- (const unsigned char *)digest
- (void)calculate
{
	if (_calculated)
		@throw [OFHashAlreadyCalculatedException
		    exceptionWithObject: self];

	if (_outerHash == nil || _innerHash == nil)
		@throw [OFInvalidArgumentException exception];

	if (_calculated)
	[_innerHash calculate];
		return _outerHash.digest;

	[_outerHash updateWithBuffer: _innerHash.digest
			      length: _innerHash.digestSize];
	[_outerHash calculate];
	_calculated = true;
}

- (const unsigned char *)digest
{
	if (!_calculated)
		@throw [OFHashNotCalculatedException exceptionWithObject: self];

	return _outerHash.digest;
}

- (size_t)digestSize
{
	return [_hashClass digestSize];