text: /**
   * \file
   * \brief CryptoAuthLib Basic API methods for Verify command.
   *
   * The Verify command takes an ECDSA [R,S] signature and verifies that it is
   * correctly generated given an input message digest and public key.
   *
   * \note List of devices that support this command - ATECC108A, ATECC508A, and
   *       ATECC608A. There are differences in the modes that they support. Refer
   *       to device datasheet for full details.
   *
   * \copyright (c) 2015-2018 Microchip Technology Inc. and its subsidiaries.
   *
   * \page License
   *
   * Subject to your compliance with these terms, you may use Microchip software
   * and any derivatives exclusively with Microchip products. It is your
   * responsibility to comply with third party license terms applicable to your
   * use of third party software (including open source software) that may
   * accompany Microchip software.
   *
   * THIS SOFTWARE IS SUPPLIED BY MICROCHIP "AS IS". NO WARRANTIES, WHETHER
   * EXPRESS, IMPLIED OR STATUTORY, APPLY TO THIS SOFTWARE, INCLUDING ANY IMPLIED
   * WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY, AND FITNESS FOR A
   * PARTICULAR PURPOSE. IN NO EVENT WILL MICROCHIP BE LIABLE FOR ANY INDIRECT,
   * SPECIAL, PUNITIVE, INCIDENTAL OR CONSEQUENTIAL LOSS, DAMAGE, COST OR EXPENSE
   * OF ANY KIND WHATSOEVER RELATED TO THE SOFTWARE, HOWEVER CAUSED, EVEN IF
   * MICROCHIP HAS BEEN ADVISED OF THE POSSIBILITY OR THE DAMAGES ARE
   * FORESEEABLE. TO THE FULLEST EXTENT ALLOWED BY LAW, MICROCHIP'S TOTAL
   * LIABILITY ON ALL CLAIMS IN ANY WAY RELATED TO THIS SOFTWARE WILL NOT EXCEED
   * THE AMOUNT OF FEES, IF ANY, THAT YOU HAVE PAID DIRECTLY TO MICROCHIP FOR
   * THIS SOFTWARE.
   */
  #include "atca_basic.h"
  #include "atca_execution.h"
  #include "host/atca_host.h"
  
  
  /** \brief Executes the Verify command, which takes an ECDSA [R,S] signature
   *          and verifies that it is correctly generated from a given message and
   *          public key. In all cases, the signature is an input to the command.
   *
   * For the Stored, External, and ValidateExternal Modes, the contents of
   * TempKey (or Message Digest Buffer in some cases for the ATECC608A) should
   * contain the 32 byte message.
   *
   * \param[in] mode        Verify command mode and options
   * \param[in] key_id      Stored mode, the slot containing the public key to
   *                        be used for the verification.
   *                        ValidateExternal mode, the slot containing the
   *                        public key to be validated.
   *                        External mode, KeyID contains the curve type to be
   *                        used to Verify the signature.
   *                        Validate or Invalidate mode, the slot containing
   *                        the public key to be (in)validated.
   * \param[in] signature   Signature to be verified. R and S integers in
   *                        big-endian format. 64 bytes for P256 curve.
   * \param[in] public_key  If mode is External, the public key to be used for
   *                        verification. X and Y integers in big-endian format.
   *                        64 bytes for P256 curve. NULL for all other modes.
   * \param[in] other_data  If mode is Validate, the bytes used to generate the
   *                        message for the validation (19 bytes). NULL for all
   *                        other modes.
   * \param[out] mac        If mode indicates a validating MAC, then the MAC will
   *                        will be returned here. Can be NULL otherwise.
   *
   * \return ATCA_SUCCESS on success, otherwise an error code.
   */
  ATCA_STATUS atcab_verify(uint8_t mode, uint16_t key_id, const uint8_t* signature, const uint8_t* public_key, const uint8_t* other_data, uint8_t* mac)
  {
      ATCAPacket packet;
      ATCACommand ca_cmd = _gDevice->mCommands;
      ATCA_STATUS status = ATCA_GEN_FAIL;
      uint8_t verify_mode = (mode & VERIFY_MODE_MASK);
  
      do
      {
          if (signature == NULL)
          {
              return ATCA_BAD_PARAM;
          }
          if (verify_mode == VERIFY_MODE_EXTERNAL && public_key == NULL)
          {
              return ATCA_BAD_PARAM;
          }
          if ((verify_mode == VERIFY_MODE_VALIDATE || verify_mode == VERIFY_MODE_INVALIDATE) && other_data == NULL)
          {
              return ATCA_BAD_PARAM;
          }
  
          // Build the verify command
          packet.param1 = mode;
          packet.param2 = key_id;
          memcpy(&packet.data[0], signature, ATCA_SIG_SIZE);
          if (verify_mode == VERIFY_MODE_EXTERNAL)
          {
              memcpy(&packet.data[ATCA_SIG_SIZE], public_key, ATCA_PUB_KEY_SIZE);
          }
          else if (other_data)
          {
              memcpy(&packet.data[ATCA_SIG_SIZE], other_data, VERIFY_OTHER_DATA_SIZE);
          }
  
          if ((status = atVerify(ca_cmd, &packet)) != ATCA_SUCCESS)
          {
              break;
          }
  
          if ((status = atca_execute_command(&packet, _gDevice)) != ATCA_SUCCESS)
          {
              break;
          }
  
          // The Verify command may return MAC if requested
          if ((mac != NULL) && (packet.data[ATCA_COUNT_IDX] >= (ATCA_PACKET_OVERHEAD + MAC_SIZE)))
          {
              memcpy(mac, &packet.data[ATCA_RSP_DATA_IDX], MAC_SIZE);
          }
  
      }
      while (false);
  
      return status;
  }
  
  /** \brief Executes the Verify command with verification MAC for the External
   *          or Stored Verify modes.. This function is only available on the
   *          ATECC608A.
   *
   * \param[in] mode          Verify command mode. Can be VERIFY_MODE_EXTERNAL or
   *                          VERIFY_MODE_STORED.
   * \param[in] key_id        For VERIFY_MODE_STORED mode, the slot containing the
   *                          public key to be used for the verification.
   *                          For VERIFY_MODE_EXTERNAL mode, KeyID contains the
   *                          curve type to be used to Verify the signature. Only
   *                          VERIFY_KEY_P256 supported.
   * \param[in]  message      32 byte message to be verified. Typically
   *                          the SHA256 hash of the full message.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  public_key   For VERIFY_MODE_EXTERNAL mode, the public key to be
   *                          used for verification. X and Y integers in
   *                          big-endian format. 64 bytes for P256 curve. Null for
   *                          VERIFY_MODE_STORED mode.
   * \param[in]  num_in       System nonce (32 byte) used for the verification
   *                          MAC.
   * \param[in]  io_key       IO protection key for verifying the validation MAC.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  static ATCA_STATUS atcab_verify_extern_stored_mac(
      uint8_t        mode,
      uint16_t       key_id,
      const uint8_t* message,
      const uint8_t* signature,
      const uint8_t* public_key,
      const uint8_t* num_in,
      const uint8_t* io_key,
      bool*          is_verified)
  {
      ATCA_STATUS status = ATCA_GEN_FAIL;
      uint8_t msg_dig_buf[64];
      atca_verify_mac_in_out_t verify_mac_params;
      uint8_t mac[SECUREBOOT_MAC_SIZE];
      uint8_t host_mac[SECUREBOOT_MAC_SIZE];
  
      do
      {
          if (is_verified == NULL)
          {
              return ATCA_BAD_PARAM;
          }
          *is_verified = false;
          if (signature == NULL || message == NULL || num_in == NULL || io_key == NULL)
          {
              return ATCA_BAD_PARAM;
          }
          if ((mode & VERIFY_MODE_MASK) == VERIFY_MODE_EXTERNAL && public_key == NULL)
          {
              return ATCA_BAD_PARAM; // Only External mode requires an external public key
  
          }
          // When using the message digest buffer as the message source, the
          // second 32 bytes in the buffer will be the MAC system nonce.
          memcpy(&msg_dig_buf[0], message, 32);
          memcpy(&msg_dig_buf[32], num_in, 32);
          if ((status = atcab_nonce_load(NONCE_MODE_TARGET_MSGDIGBUF, msg_dig_buf, 64)) != ATCA_SUCCESS)
          {
              break;
          }
  
          // Calculate the expected MAC
          memset(&verify_mac_params, 0, sizeof(verify_mac_params));
          verify_mac_params.mode = mode | VERIFY_MODE_SOURCE_MSGDIGBUF | VERIFY_MODE_MAC_FLAG;
          verify_mac_params.key_id = key_id;
          verify_mac_params.signature = signature;
          verify_mac_params.msg_dig_buf = msg_dig_buf;
          verify_mac_params.io_key = io_key;
          verify_mac_params.temp_key = NULL;
          verify_mac_params.sn = NULL;
          verify_mac_params.mac = host_mac;
          status = atcah_verify_mac(&verify_mac_params);
          if (status != ATCA_SUCCESS)
          {
              break;
          }
  
          status = atcab_verify(verify_mac_params.mode, verify_mac_params.key_id, signature, public_key, NULL, mac);
          if (status != ATCA_SUCCESS)
          {
              if (status == ATCA_CHECKMAC_VERIFY_FAILED)
              {
                  status = ATCA_SUCCESS;  // Verify failed, but command succeeded
              }
              break;
          }
  
          *is_verified = (memcmp(host_mac, mac, MAC_SIZE) == 0);
      }
      while (0);
  
      return status;
  }
  
  /** \brief Executes the Verify command, which verifies a signature (ECDSA
   *          verify operation) with all components (message, signature, and
   *          public key) supplied. The message to be signed will be loaded into
   *          the Message Digest Buffer to the ATECC608A device or TempKey for
   *          other devices.
   *
   * \param[in]  message      32 byte message to be verified. Typically
   *                          the SHA256 hash of the full message.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  public_key   The public key to be used for verification. X and
   *                          Y integers in big-endian format. 64 bytes for
   *                          P256 curve.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  ATCA_STATUS atcab_verify_extern(const uint8_t *message, const uint8_t *signature, const uint8_t *public_key, bool *is_verified)
  {
      ATCA_STATUS status = ATCA_GEN_FAIL;
      uint8_t nonce_target = NONCE_MODE_TARGET_TEMPKEY;
      uint8_t verify_source = VERIFY_MODE_SOURCE_TEMPKEY;
  
      if (is_verified == NULL)
      {
          return ATCA_BAD_PARAM;
      }
  
      *is_verified = false;
  
      if (signature == NULL || message == NULL || public_key == NULL)
      {
          return ATCA_BAD_PARAM;
      }
  
      do
      {
          // Load message into device
          if (_gDevice->mCommands->dt == ATECC608A)
          {
              // Use the Message Digest Buffer for the ATECC608A
              nonce_target = NONCE_MODE_TARGET_MSGDIGBUF;
              verify_source = VERIFY_MODE_SOURCE_MSGDIGBUF;
          }
          if ((status = atcab_nonce_load(nonce_target, message, 32)) != ATCA_SUCCESS)
          {
              break;
          }
  
          status = atcab_verify(VERIFY_MODE_EXTERNAL | verify_source, VERIFY_KEY_P256, signature, public_key, NULL, NULL);
          *is_verified = (status == ATCA_SUCCESS);
  
          if (status == ATCA_CHECKMAC_VERIFY_FAILED)
          {
              status = ATCA_SUCCESS;  // Verify failed, but command succeeded
  
          }
      }
      while (0);
  
      return status;
  }
  
  /** \brief Executes the Verify command with verification MAC, which verifies a
   *          signature (ECDSA verify operation) with all components (message,
   *          signature, and public key) supplied. This function is only available
   *          on the ATECC608A.
   *
   * \param[in]  message      32 byte message to be verified. Typically
   *                          the SHA256 hash of the full message.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  public_key   The public key to be used for verification. X and
   *                          Y integers in big-endian format. 64 bytes for
   *                          P256 curve.
   * \param[in]  num_in       System nonce (32 byte) used for the verification
   *                          MAC.
   * \param[in]  io_key       IO protection key for verifying the validation MAC.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  ATCA_STATUS atcab_verify_extern_mac(const uint8_t *message, const uint8_t* signature, const uint8_t* public_key, const uint8_t* num_in, const uint8_t* io_key, bool* is_verified)
  {
      return atcab_verify_extern_stored_mac(
          VERIFY_MODE_EXTERNAL,
          VERIFY_KEY_P256,
          message,
          signature,
          public_key,
          num_in,
          io_key,
          is_verified);
  }
  
  /** \brief Executes the Verify command, which verifies a signature (ECDSA
   *          verify operation) with a public key stored in the device. The
   *          message to be signed will be loaded into the Message Digest Buffer
   *          to the ATECC608A device or TempKey for other devices.
   *
   * \param[in]  message      32 byte message to be verified. Typically
   *                          the SHA256 hash of the full message.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  key_id       Slot containing the public key to be used in the
   *                         verification.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  ATCA_STATUS atcab_verify_stored(const uint8_t *message, const uint8_t *signature, uint16_t key_id, bool *is_verified)
  {
      ATCA_STATUS status = ATCA_GEN_FAIL;
      uint8_t nonce_target = NONCE_MODE_TARGET_TEMPKEY;
      uint8_t verify_source = VERIFY_MODE_SOURCE_TEMPKEY;
  
      if (is_verified == NULL)
      {
          return ATCA_BAD_PARAM;
      }
  
      *is_verified = false;
  
      if (signature == NULL || message == NULL)
      {
          return ATCA_BAD_PARAM;
      }
  
      do
      {
          // Load message into device
          if (_gDevice->mCommands->dt == ATECC608A)
          {
              // Use the Message Digest Buffer for the ATECC608A
              nonce_target = NONCE_MODE_TARGET_MSGDIGBUF;
              verify_source = VERIFY_MODE_SOURCE_MSGDIGBUF;
          }
          if ((status = atcab_nonce_load(nonce_target, message, 32)) != ATCA_SUCCESS)
          {
              break;
          }
  
          status = atcab_verify(VERIFY_MODE_STORED | verify_source, key_id, signature, NULL, NULL, NULL);
          *is_verified = (status == ATCA_SUCCESS);
  
          if (status == ATCA_CHECKMAC_VERIFY_FAILED)
          {
              status = ATCA_SUCCESS;  // Verify failed, but command succeeded
  
          }
      }
      while (0);
  
      return status;
  }
  
  /** \brief Executes the Verify command with verification MAC, which verifies a
   *          signature (ECDSA verify operation) with a public key stored in the
   *          device. This function is only available on the ATECC608A.
   *
   * \param[in]  message      32 byte message to be verified. Typically
   *                          the SHA256 hash of the full message.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  key_id       Slot containing the public key to be used in the
   *                          verification.
   * \param[in]  num_in       System nonce (32 byte) used for the verification
   *                          MAC.
   * \param[in]  io_key       IO protection key for verifying the validation MAC.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  ATCA_STATUS atcab_verify_stored_mac(const uint8_t *message, const uint8_t *signature, uint16_t key_id, const uint8_t* num_in, const uint8_t* io_key, bool* is_verified)
  {
      return atcab_verify_extern_stored_mac(
          VERIFY_MODE_STORED,
          key_id,
          message,
          signature,
          NULL,
          num_in,
          io_key,
          is_verified);
  }
  
  /** \brief Executes the Verify command in Validate mode to validate a public
   *          key stored in a slot.
   *
   * This command can only be run after GenKey has been used to create a PubKey
   * digest of the public key to be validated in TempKey (mode=0x10).
   *
   * \param[in]  key_id       Slot containing the public key to be validated.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  other_data   19 bytes of data used to build the verification
   *                          message.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          validation public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  ATCA_STATUS atcab_verify_validate(uint16_t key_id, const uint8_t *signature, const uint8_t *other_data, bool *is_verified)
  {
      ATCA_STATUS status = ATCA_SUCCESS;
  
      if (signature == NULL || other_data == NULL || is_verified == NULL)
      {
          return ATCA_BAD_PARAM;
      }
  
      status = atcab_verify(VERIFY_MODE_VALIDATE, key_id, signature, NULL, other_data, NULL);
      *is_verified = (status == ATCA_SUCCESS);
  
      if (status == ATCA_CHECKMAC_VERIFY_FAILED)
      {
          status = ATCA_SUCCESS;  // Verify failed, but command succeeded
  
      }
      return status;
  }
  
  /** \brief Executes the Verify command in Invalidate mode which invalidates a
   *          previously validated public key stored in a slot.
   *
   * This command can only be run after GenKey has been used to create a PubKey
   * digest of the public key to be invalidated in TempKey (mode=0x10).
   *
   * \param[in]  key_id       Slot containing the public key to be invalidated.
   * \param[in]  signature    Signature to be verified. R and S integers in
   *                          big-endian format. 64 bytes for P256 curve.
   * \param[in]  other_data   19 bytes of data used to build the verification
   *                          message.
   * \param[out] is_verified  Boolean whether or not the message, signature,
   *                          validation public key verified.
   *
   * \return ATCA_SUCCESS on verification success or failure, because the
   *         command still completed successfully.
   */
  ATCA_STATUS atcab_verify_invalidate(uint16_t key_id, const uint8_t *signature, const uint8_t *other_data, bool *is_verified)
  {
      ATCA_STATUS status = ATCA_SUCCESS;
  
      if (signature == NULL || other_data == NULL || is_verified == NULL)
      {
          return ATCA_BAD_PARAM;
      }
  
      status = atcab_verify(VERIFY_MODE_INVALIDATE, key_id, signature, NULL, other_data, NULL);
      *is_verified = (status == ATCA_SUCCESS);
  
      if (status == ATCA_CHECKMAC_VERIFY_FAILED)
      {
          status = ATCA_SUCCESS;  // Verify failed, but command succeeded
  
      }
      return status;
  }
  
  