src/core/crypto/aes_ccm.hpp

/*
 *  Copyright (c) 2016, The OpenThread Authors.
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 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 */

/**
 * @file
 *   This file includes definitions for performing AES-CCM computations.
 */

#ifndef AES_CCM_HPP_
#define AES_CCM_HPP_

#include "utils/wrap_stdint.h"

#include <openthread/types.h>

#include "crypto/aes_ecb.hpp"

namespace ot {
namespace Crypto {

/**
 * @addtogroup core-security
 *
 * @{
 *
 */

/**
 * This class implements AES CCM computation.
 *
 */
class AesCcm
{
public:
    /**
     * This method sets the key.
     *
     * @param[in]  aKey        A pointer to the key.
     * @param[in]  aKeyLength  Length of the key in bytes.
     *
     */
    otError SetKey(const uint8_t *aKey, uint16_t aKeyLength);

    /**
     * This method initializes the AES CCM computation.
     *
     * @param[in]  aHeaderLength     Length of header in bytes.
     * @param[in]  aPlainTextLength  Length of plaintext in bytes.
     * @param[in]  aTagLength        Length of tag in bytes.
     * @param[in]  aNonce            A pointer to the nonce.
     * @param[in]  aNonceLength      Length of nonce in bytes.
     *
     */
    void Init(uint32_t aHeaderLength, uint32_t aPlainTextLength, uint8_t aTagLength,
              const void *aNonce, uint8_t aNonceLength);

    /**
     * This method processes the header.
     *
     * @param[in]  aHeader        A pointer to the header.
     * @param[in]  aHeaderLength  Length of header in bytes.
     *
     */
    void Header(const void *aHeader, uint32_t aHeaderLength);

    /**
     * This method processes the payload.
     *
     * @param[inout]  aPlainText   A pointer to the plaintext.
     * @param[inout]  aCipherText  A pointer to the ciphertext.
     * @param[in]     aLength      Payload length in bytes.
     * @param[in]     aEncrypt     TRUE on encrypt and FALSE on decrypt.
     *
     */
    void Payload(void *aPlainText, void *aCipherText, uint32_t aLength, bool aEncrypt);

    /**
     * This method generates the tag.
     *
     * @param[out]  aTag        A pointer to the tag.
     * @param[out]  aTagLength  Length of the tag in bytes.
     *
     */
    void Finalize(void *aTag, uint8_t *aTagLength);

private:
    AesEcb mEcb;
    uint8_t mBlock[AesEcb::kBlockSize];
    uint8_t mCtr[AesEcb::kBlockSize];
    uint8_t mCtrPad[AesEcb::kBlockSize];
    uint8_t mNonceLength;
    uint32_t mHeaderLength;
    uint32_t mHeaderCur;
    uint32_t mPlainTextLength;
    uint32_t mPlainTextCur;
    uint16_t mBlockLength;
    uint16_t mCtrLength;
    uint8_t mTagLength;
};

/**
 * @}
 *
 */

}  // namespace Crypto
}  // namespace ot

#endif  // AES_CCM_HPP_