AesCore.c

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#include "AesCore.h"
 
//
// Number of columns (32-bit words) comprising the State.
// AES_NB is a constant (value = 4) for NIST FIPS-197.
//
#define AES_NB  4
 
//
// Pre-computed AES Forward Table: AesForwardTable[t] = AES_SBOX[t].[02, 01, 01, 03]
// AES_SBOX (AES S-box) is defined in sec 5.1.1 of FIPS PUB 197.
// This is to speed up execution of the cipher by combining SubBytes and
// ShiftRows with MixColumns steps and transforming them into table lookups.
//
GLOBAL_REMOVE_IF_UNREFERENCED CONST UINT32  AesForwardTable[] = {
  0xc66363a5, 0xf87c7c84, 0xee777799, 0xf67b7b8d, 0xfff2f20d, 0xd66b6bbd,
  0xde6f6fb1, 0x91c5c554, 0x60303050, 0x02010103, 0xce6767a9, 0x562b2b7d,
  0xe7fefe19, 0xb5d7d762, 0x4dababe6, 0xec76769a, 0x8fcaca45, 0x1f82829d,
  0x89c9c940, 0xfa7d7d87, 0xeffafa15, 0xb25959eb, 0x8e4747c9, 0xfbf0f00b,
  0x41adadec, 0xb3d4d467, 0x5fa2a2fd, 0x45afafea, 0x239c9cbf, 0x53a4a4f7,
  0xe4727296, 0x9bc0c05b, 0x75b7b7c2, 0xe1fdfd1c, 0x3d9393ae, 0x4c26266a,
  0x6c36365a, 0x7e3f3f41, 0xf5f7f702, 0x83cccc4f, 0x6834345c, 0x51a5a5f4,
  0xd1e5e534, 0xf9f1f108, 0xe2717193, 0xabd8d873, 0x62313153, 0x2a15153f,
  0x0804040c, 0x95c7c752, 0x46232365, 0x9dc3c35e, 0x30181828, 0x379696a1,
  0x0a05050f, 0x2f9a9ab5, 0x0e070709, 0x24121236, 0x1b80809b, 0xdfe2e23d,
  0xcdebeb26, 0x4e272769, 0x7fb2b2cd, 0xea75759f, 0x1209091b, 0x1d83839e,
  0x582c2c74, 0x341a1a2e, 0x361b1b2d, 0xdc6e6eb2, 0xb45a5aee, 0x5ba0a0fb,
  0xa45252f6, 0x763b3b4d, 0xb7d6d661, 0x7db3b3ce, 0x5229297b, 0xdde3e33e,
  0x5e2f2f71, 0x13848497, 0xa65353f5, 0xb9d1d168, 0x00000000, 0xc1eded2c,
  0x40202060, 0xe3fcfc1f, 0x79b1b1c8, 0xb65b5bed, 0xd46a6abe, 0x8dcbcb46,
  0x67bebed9, 0x7239394b, 0x944a4ade, 0x984c4cd4, 0xb05858e8, 0x85cfcf4a,
  0xbbd0d06b, 0xc5efef2a, 0x4faaaae5, 0xedfbfb16, 0x864343c5, 0x9a4d4dd7,
  0x66333355, 0x11858594, 0x8a4545cf, 0xe9f9f910, 0x04020206, 0xfe7f7f81,
  0xa05050f0, 0x783c3c44, 0x259f9fba, 0x4ba8a8e3, 0xa25151f3, 0x5da3a3fe,
  0x804040c0, 0x058f8f8a, 0x3f9292ad, 0x219d9dbc, 0x70383848, 0xf1f5f504,
  0x63bcbcdf, 0x77b6b6c1, 0xafdada75, 0x42212163, 0x20101030, 0xe5ffff1a,
  0xfdf3f30e, 0xbfd2d26d, 0x81cdcd4c, 0x180c0c14, 0x26131335, 0xc3ecec2f,
  0xbe5f5fe1, 0x359797a2, 0x884444cc, 0x2e171739, 0x93c4c457, 0x55a7a7f2,
  0xfc7e7e82, 0x7a3d3d47, 0xc86464ac, 0xba5d5de7, 0x3219192b, 0xe6737395,
  0xc06060a0, 0x19818198, 0x9e4f4fd1, 0xa3dcdc7f, 0x44222266, 0x542a2a7e,
  0x3b9090ab, 0x0b888883, 0x8c4646ca, 0xc7eeee29, 0x6bb8b8d3, 0x2814143c,
  0xa7dede79, 0xbc5e5ee2, 0x160b0b1d, 0xaddbdb76, 0xdbe0e03b, 0x64323256,
  0x743a3a4e, 0x140a0a1e, 0x924949db, 0x0c06060a, 0x4824246c, 0xb85c5ce4,
  0x9fc2c25d, 0xbdd3d36e, 0x43acacef, 0xc46262a6, 0x399191a8, 0x319595a4,
  0xd3e4e437, 0xf279798b, 0xd5e7e732, 0x8bc8c843, 0x6e373759, 0xda6d6db7,
  0x018d8d8c, 0xb1d5d564, 0x9c4e4ed2, 0x49a9a9e0, 0xd86c6cb4, 0xac5656fa,
  0xf3f4f407, 0xcfeaea25, 0xca6565af, 0xf47a7a8e, 0x47aeaee9, 0x10080818,
  0x6fbabad5, 0xf0787888, 0x4a25256f, 0x5c2e2e72, 0x381c1c24, 0x57a6a6f1,
  0x73b4b4c7, 0x97c6c651, 0xcbe8e823, 0xa1dddd7c, 0xe874749c, 0x3e1f1f21,
  0x964b4bdd, 0x61bdbddc, 0x0d8b8b86, 0x0f8a8a85, 0xe0707090, 0x7c3e3e42,
  0x71b5b5c4, 0xcc6666aa, 0x904848d8, 0x06030305, 0xf7f6f601, 0x1c0e0e12,
  0xc26161a3, 0x6a35355f, 0xae5757f9, 0x69b9b9d0, 0x17868691, 0x99c1c158,
  0x3a1d1d27, 0x279e9eb9, 0xd9e1e138, 0xebf8f813, 0x2b9898b3, 0x22111133,
  0xd26969bb, 0xa9d9d970, 0x078e8e89, 0x339494a7, 0x2d9b9bb6, 0x3c1e1e22,
  0x15878792, 0xc9e9e920, 0x87cece49, 0xaa5555ff, 0x50282878, 0xa5dfdf7a,
  0x038c8c8f, 0x59a1a1f8, 0x09898980, 0x1a0d0d17, 0x65bfbfda, 0xd7e6e631,
  0x844242c6, 0xd06868b8, 0x824141c3, 0x299999b0, 0x5a2d2d77, 0x1e0f0f11,
  0x7bb0b0cb, 0xa85454fc, 0x6dbbbbd6, 0x2c16163a
};
 
//
// Round constant word array used in AES key expansion.
//
GLOBAL_REMOVE_IF_UNREFERENCED CONST UINT32  Rcon[] = {
  0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000,
  0x20000000, 0x40000000, 0x80000000, 0x1B000000, 0x36000000
};
 
//
// Rotates x right n bits (circular right shift operation)
//
#define ROTATE_RIGHT32(x, n)  (((x) >> (n)) | ((x) << (32-(n))))
 
//
// Loading & Storing 32-bit words in big-endian format: y[3..0] --> x; x --> y[3..0];
//
#define LOAD32H(x, y)   { x = ((UINT32)((y)[0] & 0xFF) << 24) | ((UINT32)((y)[1] & 0xFF) << 16) |   \
                               ((UINT32)((y)[2] & 0xFF) <<  8) | ((UINT32)((y)[3] & 0xFF)); }
#define STORE32H(x, y)  { (y)[0] = (UINT8)(((x) >> 24) & 0xFF); (y)[1] = (UINT8)(((x) >> 16) & 0xFF);  \
                           (y)[2] = (UINT8)(((x) >>  8) & 0xFF); (y)[3] = (UINT8)((x)         & 0xFF); }
 
//
// Wrap macros for AES forward tables lookups
//
#define AES_FT0(x)  AesForwardTable[x]
#define AES_FT1(x)  ROTATE_RIGHT32(AesForwardTable[x],  8)
#define AES_FT2(x)  ROTATE_RIGHT32(AesForwardTable[x], 16)
#define AES_FT3(x)  ROTATE_RIGHT32(AesForwardTable[x], 24)
 
typedef struct {
  UINTN     Nk;            // Number of Cipher Key (in 32-bit words);
  UINT32    EncKey[60];    // Expanded AES encryption key
  UINT32    DecKey[60];    // Expanded AES decryption key (Not used here)
} AES_KEY;
 
EFI_STATUS
EFIAPI
AesExpandKey (
  IN UINT8     *Key,
  IN UINTN     KeyLenInBits,
  OUT AES_KEY  *AesKey
  )
{
  UINTN   Nk;
  UINTN   Nr;
  UINTN   Nw;
  UINTN   Index1;
  UINTN   Index2;
  UINTN   Index3;
  UINT32  *Ek;
  UINT32  Temp;
 
  //
  // Nk - Number of 32-bit words comprising the cipher key. (Nk = 4, 6 or 8)
  // Nr - Number of rounds. (Nr = 10, 12, or 14), which is dependent on the key size.
  //
  Nk = KeyLenInBits >> 5;
  if ((Nk != 4) && (Nk != 6) && (Nk != 8)) {
    return EFI_INVALID_PARAMETER;
  }
 
  Nr         = Nk + 6;
  Nw         = AES_NB * (Nr + 1); // Key Expansion generates a total of Nb * (Nr + 1) words
  AesKey->Nk = Nk;
 
  //
  // Load initial symmetric AES key;
  // Note that AES was designed on big-endian systems.
  //
  Ek = AesKey->EncKey;
  for (Index1 = Index2 = 0; Index1 < Nk; Index1++, Index2 += 4) {
    LOAD32H (Ek[Index1], Key + Index2);
  }
 
  //
  // Initialize the encryption key scheduler
  //
  for (Index2 = Nk, Index3 = 0; Index2 < Nw; Index2 += Nk, Index3++) {
    Temp       = Ek[Index2 - 1];
    Ek[Index2] = Ek[Index2 - Nk] ^ (AES_FT2 ((Temp >> 16) & 0xFF) & 0xFF000000) ^
                 (AES_FT3 ((Temp >>  8) & 0xFF) & 0x00FF0000) ^
                 (AES_FT0 ((Temp)       & 0xFF) & 0x0000FF00) ^
                 (AES_FT1 ((Temp >> 24) & 0xFF) & 0x000000FF) ^
                 Rcon[Index3];
    if (Nk <= 6) {
      //
      // If AES Cipher Key is 128 or 192 bits
      //
      for (Index1 = 1; Index1 < Nk && (Index1 + Index2) < Nw; Index1++) {
        Ek[Index1 + Index2] = Ek[Index1 + Index2 - Nk] ^ Ek[Index1 + Index2 - 1];
      }
    } else {
      //
      // Different routine for key expansion If Cipher Key is 256 bits,
      //
      for (Index1 = 1; Index1 < 4 && (Index1 + Index2) < Nw; Index1++) {
        Ek[Index1 + Index2] = Ek[Index1 + Index2 - Nk] ^ Ek[Index1 + Index2 - 1];
      }
 
      if (Index2 + 4 < Nw) {
        Temp           = Ek[Index2 + 3];
        Ek[Index2 + 4] = Ek[Index2 + 4 - Nk] ^ (AES_FT2 ((Temp >> 24) & 0xFF) & 0xFF000000) ^
                         (AES_FT3 ((Temp >> 16) & 0xFF) & 0x00FF0000) ^
                         (AES_FT0 ((Temp >>  8) & 0xFF) & 0x0000FF00) ^
                         (AES_FT1 ((Temp)       & 0xFF) & 0x000000FF);
      }
 
      for (Index1 = 5; Index1 < Nk && (Index1 + Index2) < Nw; Index1++) {
        Ek[Index1 + Index2] = Ek[Index1 + Index2 - Nk] ^ Ek[Index1 + Index2 - 1];
      }
    }
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
AesEncrypt (
  IN  UINT8  *Key,
  IN  UINT8  *InData,
  OUT UINT8  *OutData
  )
{
  AES_KEY  AesKey;
  UINTN    Nr;
  UINT32   *Ek;
  UINT32   State[4];
  UINT32   TempState[4];
  UINT32   *StateX;
  UINT32   *StateY;
  UINT32   *Temp;
  UINTN    Index;
  UINTN    NbIndex;
  UINTN    Round;
 
  if ((Key == NULL) || (InData == NULL) || (OutData == NULL)) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Expands AES Key for encryption.
  //
  AesExpandKey (Key, 128, &AesKey);
 
  Nr = AesKey.Nk + 6;
  Ek = AesKey.EncKey;
 
  //
  // Initialize the cipher State array with the initial round key
  //
  for (Index = 0; Index < AES_NB; Index++) {
    LOAD32H (State[Index], InData + 4 * Index);
    State[Index] ^= Ek[Index];
  }
 
  NbIndex = AES_NB;
  StateX  = State;
  StateY  = TempState;
 
  //
  // AES Cipher transformation rounds (Nr - 1 rounds), in which SubBytes(),
  // ShiftRows() and MixColumns() operations were combined by a sequence of
  // table lookups to speed up the execution.
  //
  for (Round = 1; Round < Nr; Round++) {
    StateY[0] = AES_FT0 ((StateX[0] >> 24)) ^ AES_FT1 ((StateX[1] >> 16) & 0xFF) ^
                AES_FT2 ((StateX[2] >>  8) & 0xFF) ^ AES_FT3 ((StateX[3]) & 0xFF) ^ Ek[NbIndex];
    StateY[1] = AES_FT0 ((StateX[1] >> 24)) ^ AES_FT1 ((StateX[2] >> 16) & 0xFF) ^
                AES_FT2 ((StateX[3] >>  8) & 0xFF) ^ AES_FT3 ((StateX[0]) & 0xFF) ^ Ek[NbIndex + 1];
    StateY[2] = AES_FT0 ((StateX[2] >> 24)) ^ AES_FT1 ((StateX[3] >> 16) & 0xFF) ^
                AES_FT2 ((StateX[0] >>  8) & 0xFF) ^ AES_FT3 ((StateX[1]) & 0xFF) ^ Ek[NbIndex + 2];
    StateY[3] = AES_FT0 ((StateX[3] >> 24)) ^ AES_FT1 ((StateX[0] >> 16) & 0xFF) ^
                AES_FT2 ((StateX[1] >>  8) & 0xFF) ^ AES_FT3 ((StateX[2]) & 0xFF) ^ Ek[NbIndex + 3];
 
    NbIndex += 4;
    Temp     = StateX;
    StateX   = StateY;
    StateY   = Temp;
  }
 
  //
  // Apply the final round, which does not include MixColumns() transformation
  //
  StateY[0] = (AES_FT2 ((StateX[0] >> 24)) & 0xFF000000) ^ (AES_FT3 ((StateX[1] >> 16) & 0xFF) & 0x00FF0000) ^
              (AES_FT0 ((StateX[2] >>  8) & 0xFF) & 0x0000FF00) ^ (AES_FT1 ((StateX[3]) & 0xFF) & 0x000000FF) ^
              Ek[NbIndex];
  StateY[1] = (AES_FT2 ((StateX[1] >> 24)) & 0xFF000000) ^ (AES_FT3 ((StateX[2] >> 16) & 0xFF) & 0x00FF0000) ^
              (AES_FT0 ((StateX[3] >>  8) & 0xFF) & 0x0000FF00) ^ (AES_FT1 ((StateX[0]) & 0xFF) & 0x000000FF) ^
              Ek[NbIndex + 1];
  StateY[2] = (AES_FT2 ((StateX[2] >> 24)) & 0xFF000000) ^ (AES_FT3 ((StateX[3] >> 16) & 0xFF) & 0x00FF0000) ^
              (AES_FT0 ((StateX[0] >>  8) & 0xFF) & 0x0000FF00) ^ (AES_FT1 ((StateX[1]) & 0xFF) & 0x000000FF) ^
              Ek[NbIndex + 2];
  StateY[3] = (AES_FT2 ((StateX[3] >> 24)) & 0xFF000000) ^ (AES_FT3 ((StateX[0] >> 16) & 0xFF) & 0x00FF0000) ^
              (AES_FT0 ((StateX[1] >>  8) & 0xFF) & 0x0000FF00) ^ (AES_FT1 ((StateX[2]) & 0xFF) & 0x000000FF) ^
              Ek[NbIndex + 3];
 
  //
  // Output the transformed result;
  //
  for (Index = 0; Index < AES_NB; Index++) {
    STORE32H (StateY[Index], OutData + 4 * Index);
  }
 
  return EFI_SUCCESS;
}