/* * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 * Jonathan Schleifer <js@heap.zone> * * 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. */ #import "OFObject.h" #import "OFCryptoHash.h" OF_ASSUME_NONNULL_BEGIN /*! * @class OFHMAC OFHMAC.h ObjFW/OFHMAC.h * * @brief A class which provides methods to calculate an HMAC. */ @interface OFHMAC: OFObject { Class <OFCryptoHash> _hashClass; id <OFCryptoHash> _Nullable _outerHash, _innerHash; id <OFCryptoHash> _Nullable _outerHashCopy, _innerHashCopy; bool _calculated; } /*! * @brief The class for the cryptographic hash used by the HMAC. */ @property (readonly, nonatomic) Class <OFCryptoHash> hashClass; /*! * @brief A buffer containing the HMAC. * * The size of the buffer depends on the hash used. The buffer is part of the * receiver's memory pool. */ @property (readonly, nonatomic) const unsigned char *digest OF_RETURNS_INNER_POINTER; /*! * @brief The size of the digest. */ @property (readonly, nonatomic) size_t digestSize; /*! * @brief Returns a new OFHMAC with the specified hashing algorithm. * * @param hashClass The class of the hashing algorithm * @return A new, autoreleased OFHMAC */ + (instancetype)HMACWithHashClass: (Class <OFCryptoHash>)hashClass; - (instancetype)init OF_UNAVAILABLE; /*! * @brief Initialized an already allocated OFHMAC with the specified hashing * algorithm. * * @param hashClass The class of the hashing algorithm * @return An initialized OFHMAC */ - (instancetype)initWithHashClass: (Class <OFCryptoHash>)hashClass OF_DESIGNATED_INITIALIZER; /*! * @brief Sets the key for the HMAC. * * @note This resets the HMAC! * * @warning This invalidates any pointer previously returned by @ref digest. If * you are still interested in the previous digest, you need to memcpy * it yourself before calling @ref setKey:length:! * * @param key The key for the HMAC * @param length The length of the key for the HMAC */ - (void)setKey: (const void *)key length: (size_t)length; /*! * @brief Adds a buffer to the HMAC to be calculated. * * @param buffer The buffer which should be included into the calculation * @param length The length of the buffer */ - (void)updateWithBuffer: (const void *)buffer length: (size_t)length; /*! * @brief Resets the HMAC so that it can be calculated for a new message. * * @note This does not reset the key so that a new HMAC with the same key can * be calculated efficiently. If you want to reset both, use * @ref setKey:length:. * * @warning This invalidates any pointer previously returned by @ref digest. If * you are still interested in the previous digest, you need to memcpy * it yourself before calling @ref reset! */ - (void)reset; /*! * @brief This is like @ref reset, but also zeroes the hashed key and all state. * * @warning After calling this, you *must* set a new key before reusing the * HMAC! */ - (void)zero; @end OF_ASSUME_NONNULL_END