em_aes.c

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/***************************************************************************/
#include "em_aes.h"
#if defined(AES_COUNT) && (AES_COUNT > 0)

#include "em_assert.h"
/***************************************************************************/
/***************************************************************************/
/*******************************************************************************
 *******************************   DEFINES   ***********************************
 ******************************************************************************/

#define AES_BLOCKSIZE    16

/*******************************************************************************
 **************************   GLOBAL FUNCTIONS   *******************************
 ******************************************************************************/

/***************************************************************************/
void AES_CBC128(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                const uint8_t *iv,
                bool encrypt)
{
  int            i;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  const uint32_t *_iv  = (const uint32_t *)iv;
  /* Need to buffer one block when decrypting in case 'out' replaces 'in' */
  uint32_t       prev[4];

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  /* Number of blocks to process */
  len /= AES_BLOCKSIZE;

  #if defined( AES_CTRL_KEYBUFEN )
  if (key)
  {
    /* Load key into high key for key buffer usage */
    for (i = 3; i >= 0; i--)
    {
      AES->KEYHA = __REV(_key[i]);
    }
  }
  #endif

  if (encrypt)
  {
    /* Enable encryption with auto start using XOR */
    #if defined( AES_CTRL_KEYBUFEN )
    AES->CTRL = AES_CTRL_KEYBUFEN | AES_CTRL_XORSTART;
    #else
    AES->CTRL = AES_CTRL_XORSTART;
    #endif

    /* Load initialization vector, since writing to DATA, it will */
    /* not trigger encryption. */
    for (i = 3; i >= 0; i--)
    {
      AES->DATA = __REV(_iv[i]);
    }

    /* Encrypt data */
    while (len--)
    {
      #if !defined( AES_CTRL_KEYBUFEN )
      /* Load key */
      for (i = 3; i >= 0; i--)
      {
        AES->KEYLA = __REV(_key[i]);
      }
      #endif

      /* Load data and trigger encryption */
      for (i = 3; i >= 0; i--)
      {
        AES->XORDATA = __REV(_in[i]);
      }
      _in += 4;

      /* Wait for completion */
      while (AES->STATUS & AES_STATUS_RUNNING)
        ;

      /* Save encrypted data */
      for (i = 3; i >= 0; i--)
      {
        _out[i] = __REV(AES->DATA);
      }
      _out += 4;
    }
  }
  else
  {
    /* Select decryption mode */
    #if defined( AES_CTRL_KEYBUFEN )
    AES->CTRL = AES_CTRL_DECRYPT | AES_CTRL_KEYBUFEN | AES_CTRL_DATASTART;
    #else
    AES->CTRL = AES_CTRL_DECRYPT | AES_CTRL_DATASTART;
    #endif

    /* Copy init vector to previous buffer to avoid special handling */
    for (i = 0; i < 4; i++)
    {
      prev[i] = _iv[i];
    }

    /* Decrypt data */
    while (len--)
    {
      #if !defined( AES_CTRL_KEYBUFEN )
      /* Load key */
      for (i = 3; i >= 0; i--)
      {
        AES->KEYLA = __REV(_key[i]);
      }
      #endif

      /* Load data and trigger decryption */
      for (i = 3; i >= 0; i--)
      {
        AES->DATA = __REV(_in[i]);
      }

      /* Wait for completion */
      while (AES->STATUS & AES_STATUS_RUNNING)
        ;

      /* In order to avoid additional buffer, we use HW directly for XOR and buffer */
      /* (Writing to XORDATA will not trigger encoding, triggering enabled on DATA.) */
      for (i = 3; i >= 0; i--)
      {
        AES->XORDATA = __REV(prev[i]);
        prev[i]      = _in[i];
      }
      _in += 4;

      /* Then fetch decrypted data, we have to do it in a separate loop */
      /* due to internal auto-shifting of words */
      for (i = 3; i >= 0; i--)
      {
        _out[i] = __REV(AES->DATA);
      }
      _out += 4;
    }
  }
}


#if defined( AES_CTRL_AES256 )
/***************************************************************************/
void AES_CBC256(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                const uint8_t *iv,
                bool encrypt)
{
  int            i;
  int            j;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  const uint32_t *_iv  = (const uint32_t *)iv;
  /* Need to buffer one block when decrypting in case output replaces input */
  uint32_t       prev[4];

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  /* Number of blocks to process */
  len /= AES_BLOCKSIZE;

  if (encrypt)
  {
    /* Enable encryption with auto start using XOR */
    AES->CTRL = AES_CTRL_AES256 | AES_CTRL_XORSTART;

    /* Load initialization vector, since writing to DATA, it will */
    /* not trigger encryption. */
    for (i = 3; i >= 0; i--)
    {
      AES->DATA = __REV(_iv[i]);
    }

    /* Encrypt data */
    while (len--)
    {
      /* Load key and data and trigger encryption */
      for (i = 3, j = 7; i >= 0; i--, j--)
      {
        AES->KEYLA = __REV(_key[j]);
        AES->KEYHA = __REV(_key[i]);
        /* Write data last, since will trigger encryption on last iteration */
        AES->XORDATA = __REV(_in[i]);
      }
      _in += 4;

      /* Wait for completion */
      while (AES->STATUS & AES_STATUS_RUNNING)
        ;

      /* Save encrypted data */
      for (i = 3; i >= 0; i--)
      {
        _out[i] = __REV(AES->DATA);
      }
      _out += 4;
    }
  }
  else
  {
    /* Select decryption mode */
    AES->CTRL = AES_CTRL_AES256 | AES_CTRL_DECRYPT | AES_CTRL_DATASTART;

    /* Copy init vector to previous buffer to avoid special handling */
    for (i = 0; i < 4; i++)
    {
      prev[i] = _iv[i];
    }

    /* Decrypt data */
    while (len--)
    {
      /* Load key and data and trigger decryption */
      for (i = 3, j = 7; i >= 0; i--, j--)
      {
        AES->KEYLA = __REV(_key[j]);
        AES->KEYHA = __REV(_key[i]);
        /* Write data last, since will trigger encryption on last iteration */
        AES->DATA = __REV(_in[i]);
      }

      /* Wait for completion */
      while (AES->STATUS & AES_STATUS_RUNNING)
        ;

      /* In order to avoid additional buffer, we use HW directly for XOR and buffer */
      for (i = 3; i >= 0; i--)
      {
        AES->XORDATA = __REV(prev[i]);
        prev[i]      = _in[i];
      }
      _in += 4;

      /* Then fetch decrypted data, we have to do it in a separate loop */
      /* due to internal auto-shifting of words */
      for (i = 3; i >= 0; i--)
      {
        _out[i] = __REV(AES->DATA);
      }
      _out += 4;
    }
  }
}
#endif


/***************************************************************************/
void AES_CFB128(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                const uint8_t *iv,
                bool encrypt)
{
  int            i;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  const uint32_t *_iv  = (const uint32_t *)iv;
  const uint32_t *data;
  uint32_t       tmp[4];

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  #if defined( AES_CTRL_KEYBUFEN )
  AES->CTRL = AES_CTRL_KEYBUFEN | AES_CTRL_DATASTART;
  #else
  AES->CTRL = AES_CTRL_DATASTART;
  #endif

  #if defined( AES_CTRL_KEYBUFEN )
  /* Load key into high key for key buffer usage */
  for (i = 3; i >= 0; i--)
  {
    AES->KEYHA = __REV(_key[i]);
  }
  #endif

  /* Encrypt/decrypt data */
  data = _iv;
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    #if !defined( AES_CTRL_KEYBUFEN )
    /* Load key */
    for (i = 3; i >= 0; i--)
    {
      AES->KEYLA = __REV(_key[i]);
    }
    #endif

    /* Load data and trigger encryption */
    for (i = 3; i >= 0; i--)
    {
      AES->DATA = __REV(data[i]);
    }

    /* Do some required processing before waiting for completion */
    if (encrypt)
    {
      data = _out;
    }
    else
    {
      /* Must copy current ciphertext block since it may be overwritten */
      for (i = 0; i < 4; i++)
      {
        tmp[i] = _in[i];
      }
      data = tmp;
    }

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA) ^ _in[i];
    }
    _out += 4;
    _in  += 4;
  }
}


#if defined( AES_CTRL_AES256 )
/***************************************************************************/
void AES_CFB256(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                const uint8_t *iv,
                bool encrypt)
{
  int            i;
  int            j;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  const uint32_t *_iv  = (const uint32_t *)iv;
  const uint32_t *data;
  uint32_t       tmp[4];

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  /* Select encryption mode */
  AES->CTRL = AES_CTRL_AES256 | AES_CTRL_DATASTART;

  /* Encrypt/decrypt data */
  data = _iv;
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    /* Load key and block to be encrypted/decrypted */
    for (i = 3, j = 7; i >= 0; i--, j--)
    {
      AES->KEYLA = __REV(_key[j]);
      AES->KEYHA = __REV(_key[i]);
      /* Write data last, since will trigger encryption on last iteration */
      AES->DATA = __REV(data[i]);
    }

    /* Do some required processing before waiting for completion */
    if (encrypt)
    {
      data = _out;
    }
    else
    {
      /* Must copy current ciphertext block since it may be overwritten */
      for (i = 0; i < 4; i++)
      {
        tmp[i] = _in[i];
      }
      data = tmp;
    }

    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA) ^ _in[i];
    }
    _out += 4;
    _in  += 4;
  }
}
#endif


/***************************************************************************/
void AES_CTR128(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                uint8_t *ctr,
                AES_CtrFuncPtr_TypeDef ctrFunc)
{
  int            i;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  uint32_t       *_ctr = (uint32_t *)ctr;

  EFM_ASSERT(!(len % AES_BLOCKSIZE));
  EFM_ASSERT(ctrFunc);

  #if defined( AES_CTRL_KEYBUFEN )
  AES->CTRL = AES_CTRL_KEYBUFEN | AES_CTRL_DATASTART;
  #else
  AES->CTRL = AES_CTRL_DATASTART;
  #endif

  #if defined( AES_CTRL_KEYBUFEN )
  if (key)
  {
    /* Load key into high key for key buffer usage */
    for (i = 3; i >= 0; i--)
    {
      AES->KEYHA = __REV(_key[i]);
    }
  }
  #endif

  /* Encrypt/decrypt data */
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    #if !defined( AES_CTRL_KEYBUFEN )
    /* Load key */
    for (i = 3; i >= 0; i--)
    {
      AES->KEYLA = __REV(_key[i]);
    }
    #endif

    /* Load ctr to be encrypted/decrypted */
    for (i = 3; i >= 0; i--)
    {
      AES->DATA = __REV(_ctr[i]);
    }
    /* Increment ctr for next use */
    ctrFunc(ctr);

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA) ^ _in[i];
    }
    _out += 4;
    _in  += 4;
  }
}


#if defined( AES_CTRL_AES256 )
/***************************************************************************/
void AES_CTR256(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                uint8_t *ctr,
                AES_CtrFuncPtr_TypeDef ctrFunc)
{
  int            i;
  int            j;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  uint32_t       *_ctr = (uint32_t *)ctr;

  EFM_ASSERT(!(len % AES_BLOCKSIZE));
  EFM_ASSERT(ctrFunc);

  /* Select encryption mode, with auto trigger */
  AES->CTRL = AES_CTRL_AES256 | AES_CTRL_DATASTART;

  /* Encrypt/decrypt data */
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    /* Load key and block to be encrypted/decrypted */
    for (i = 3, j = 7; i >= 0; i--, j--)
    {
      AES->KEYLA = __REV(_key[j]);
      AES->KEYHA = __REV(_key[i]);
      /* Write data last, since will trigger encryption on last iteration */
      AES->DATA = __REV(_ctr[i]);
    }
    /* Increment ctr for next use */
    ctrFunc(ctr);

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA) ^ _in[i];
    }
    _out += 4;
    _in  += 4;
  }
}
#endif


/***************************************************************************/
void AES_CTRUpdate32Bit(uint8_t *ctr)
{
  uint32_t *_ctr = (uint32_t *)ctr;

  _ctr[3] = __REV(__REV(_ctr[3]) + 1);
}


/***************************************************************************/
void AES_DecryptKey128(uint8_t *out, const uint8_t *in)
{
  int            i;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;

  /* Load key */
  for (i = 3; i >= 0; i--)
  {
    AES->KEYLA = __REV(_in[i]);
  }

  /* Do dummy encryption to generate decrypt key */
  AES->CTRL = 0;
  AES_IntClear(AES_IF_DONE);
  AES->CMD = AES_CMD_START;

  /* Wait for completion */
  while (AES->STATUS & AES_STATUS_RUNNING)
    ;

  /* Save decryption key */
  for (i = 3; i >= 0; i--)
  {
    _out[i] = __REV(AES->KEYLA);
  }
}


#if defined( AES_CTRL_AES256 )
/***************************************************************************/
void AES_DecryptKey256(uint8_t *out, const uint8_t *in)
{
  int            i;
  int            j;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;

  /* Load key */
  for (i = 3, j = 7; i >= 0; i--, j--)
  {
    AES->KEYLA = __REV(_in[j]);
    AES->KEYHA = __REV(_in[i]);
  }

  /* Do dummy encryption to generate decrypt key */
  AES->CTRL = AES_CTRL_AES256;
  AES->CMD  = AES_CMD_START;

  /* Wait for completion */
  while (AES->STATUS & AES_STATUS_RUNNING)
    ;

  /* Save decryption key */
  for (i = 3, j = 7; i >= 0; i--, j--)
  {
    _out[j] = __REV(AES->KEYLA);
    _out[i] = __REV(AES->KEYHA);
  }
}
#endif


/***************************************************************************/
void AES_ECB128(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                bool encrypt)
{
  int            i;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  #if defined( AES_CTRL_KEYBUFEN )
  /* Load key into high key for key buffer usage */
  for (i = 3; i >= 0; i--)
  {
    AES->KEYHA = __REV(_key[i]);
  }
  #endif

  if (encrypt)
  {
    /* Select encryption mode */
    #if defined( AES_CTRL_KEYBUFEN )
    AES->CTRL = AES_CTRL_KEYBUFEN | AES_CTRL_DATASTART;
    #else
    AES->CTRL = AES_CTRL_DATASTART;
    #endif
  }
  else
  {
    /* Select decryption mode */
    #if defined( AES_CTRL_KEYBUFEN )
    AES->CTRL = AES_CTRL_DECRYPT | AES_CTRL_KEYBUFEN | AES_CTRL_DATASTART;
    #else
    AES->CTRL = AES_CTRL_DECRYPT | AES_CTRL_DATASTART;
    #endif
  }

  /* Encrypt/decrypt data */
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    #if !defined( AES_CTRL_KEYBUFEN )
    /* Load key */
    for (i = 3; i >= 0; i--)
    {
      AES->KEYLA = __REV(_key[i]);
    }
    #endif

    /* Load block to be encrypted/decrypted */
    for (i = 3; i >= 0; i--)
    {
      AES->DATA = __REV(_in[i]);
    }
    _in += 4;

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA);
    }
    _out += 4;
  }
}


#if defined( AES_CTRL_AES256 )
/***************************************************************************/
void AES_ECB256(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                bool encrypt)
{
  int            i;
  int            j;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  if (encrypt)
  {
    /* Select encryption mode */
    AES->CTRL = AES_CTRL_AES256 | AES_CTRL_DATASTART;
  }
  else
  {
    /* Select decryption mode */
    AES->CTRL = AES_CTRL_DECRYPT | AES_CTRL_AES256 | AES_CTRL_DATASTART;
  }

  /* Encrypt/decrypt data */
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    /* Load key and block to be encrypted/decrypted */
    for (i = 3, j = 7; i >= 0; i--, j--)
    {
      AES->KEYLA = __REV(_key[j]);
      AES->KEYHA = __REV(_key[i]);
      /* Write data last, since will trigger encryption on last iteration */
      AES->DATA = __REV(_in[i]);
    }
    _in += 4;

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA);
    }
    _out += 4;
  }
}
#endif


/***************************************************************************/
void AES_OFB128(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                const uint8_t *iv)
{
  int            i;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  const uint32_t *_iv  = (const uint32_t *)iv;

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  /* Select encryption mode, trigger explicitly by command */
  #if defined( AES_CTRL_KEYBUFEN )
  AES->CTRL = AES_CTRL_KEYBUFEN;
  #else
  AES->CTRL = 0;
  #endif

  /* Load key into high key for key buffer usage */
  /* Load initialization vector */
  for (i = 3; i >= 0; i--)
  {
    #if defined( AES_CTRL_KEYBUFEN )
    AES->KEYHA = __REV(_key[i]);
    #endif
    AES->DATA  = __REV(_iv[i]);
  }

  /* Encrypt/decrypt data */
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    #if !defined( AES_CTRL_KEYBUFEN )
    /* Load key */
    for (i = 3; i >= 0; i--)
    {
      AES->KEYLA = __REV(_key[i]);
    }
    #endif

    AES->CMD = AES_CMD_START;

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA) ^ _in[i];
    }
    _out += 4;
    _in  += 4;
  }
}


#if defined( AES_CTRL_AES256 )
/***************************************************************************/
void AES_OFB256(uint8_t *out,
                const uint8_t *in,
                unsigned int len,
                const uint8_t *key,
                const uint8_t *iv)
{
  int            i;
  int            j;
  uint32_t       *_out = (uint32_t *)out;
  const uint32_t *_in  = (const uint32_t *)in;
  const uint32_t *_key = (const uint32_t *)key;
  const uint32_t *_iv  = (const uint32_t *)iv;

  EFM_ASSERT(!(len % AES_BLOCKSIZE));

  /* Select encryption mode, trigger explicitly by command */
  AES->CTRL = AES_CTRL_AES256;

  /* Load initialization vector */
  for (i = 3; i >= 0; i--)
  {
    AES->DATA = __REV(_iv[i]);
  }

  /* Encrypt/decrypt data */
  len /= AES_BLOCKSIZE;
  while (len--)
  {
    /* Load key */
    for (i = 3, j = 7; i >= 0; i--, j--)
    {
      AES->KEYLA = __REV(_key[j]);
      AES->KEYHA = __REV(_key[i]);
    }

    AES->CMD = AES_CMD_START;

    /* Wait for completion */
    while (AES->STATUS & AES_STATUS_RUNNING)
      ;

    /* Save encrypted/decrypted data */
    for (i = 3; i >= 0; i--)
    {
      _out[i] = __REV(AES->DATA) ^ _in[i];
    }
    _out += 4;
    _in  += 4;
  }
}
#endif


#endif /* defined(AES_COUNT) && (AES_COUNT > 0) */