aes boolean masking

Signed-off-by: Shelly Liberman <shelly.liberman@arm.com>

configs/baremetal.h

@@ -42,6 +42,7 @@
 #define MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
 #define MBEDTLS_AES_ONLY_ENCRYPT
 #define MBEDTLS_AES_SCA_COUNTERMEASURES
+#define MBEDTLS_AES_128_BIT_MASKED
 #define MBEDTLS_CCM_C
 
 /* Asymmetric crypto: Single-curve ECC only. */

include/mbedtls/aes.h

@@ -83,6 +83,10 @@ extern "C" {
 /**
  * \brief The AES context-type definition.
  */
+
+//#if defined(MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH)
+#define AES_128_EXPANDED_KEY_SIZE_IN_WORDS 44
+//#endif
 typedef struct mbedtls_aes_context
 {
     int nr;                     /*!< The number of rounds. */
@@ -94,7 +98,7 @@ typedef struct mbedtls_aes_context
     uint32_t hash;               /*!< hash of the set key */
 #endif
 #if defined(MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH) && !defined(MBEDTLS_PADLOCK_C)
-    uint32_t buf[44];           /*!< Unaligned data buffer */
+    uint32_t buf[AES_128_EXPANDED_KEY_SIZE_IN_WORDS];           /*!< Unaligned data buffer for expanded key only */
 #else /* MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH */
     uint32_t buf[68];           /*!< Unaligned data buffer. This buffer can
                                      hold 32 extra Bytes, which can be used for

include/mbedtls/config.h

@@ -654,6 +654,25 @@
  */
 //#define MBEDTLS_AES_SCA_COUNTERMEASURES
 
+/**
+ * \def MBEDTLS_AES_128_BIT_MASKED
+ *
+ * Requires MBEDTLS_AES_SCA_COUNTERMEASURES
+ * 
+ * Add boolean masking against possible combined side-channel-attack fault injection attacks.
+ *
+ * Uncommenting this macro adds data, key and Sbox masking additionally to dummy rounds
+ *
+ * Tradeoff:
+ * Uncommenting this macro does not increase codesize in MBEDTLS_AES_ROM_TABLES configuration.
+ * Uncommenting this macro increases codesize in AES RAM tables configuration by ~1k.
+ * The performance loss is ~50% with 128 bit AES encrypt.
+ *
+ * This option is dependent of \c MBEDTLS_ENTROPY_HARDWARE_ALT.
+ *
+ */
+//#define MBEDTLS_AES_128_BIT_MASKED
+
 /**
  * \def MBEDTLS_FI_COUNTERMEASURES
  *

library/aes.c

@@ -91,11 +91,25 @@
 typedef struct {
     uint32_t *rk_ptr;       /* Round Key */
     uint32_t xy_values[8];  /* X0, X1, X2, X3, Y0, Y1, Y2, Y3 */
+#if defined(MBEDTLS_AES_128_BIT_MASKED)
+    uint32_t round;
+#endif
 } aes_r_data_t;
 
 #if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
 /* Number of additional AES dummy rounds added for SCA countermeasures */
 #define AES_SCA_CM_ROUNDS  5
+
+#if defined (MBEDTLS_AES_128_BIT_MASKED)
+
+#define Nb (4)  /* number of columns (32-bit words) comprising the state */
+#define Nk (4)  /* number of 32-bit words comprising the key */
+#define Nr (10) /* number of rounds */
+
+// state - array holding the intermediate results during aes operation.
+typedef uint8_t masked_state_t[4][4];
+
+#endif
 #endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
 
 #if defined(MBEDTLS_PADLOCK_C) &&                      \
@@ -143,6 +157,8 @@ static const unsigned char FSb[256] =
     0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
 };
 
+
+#if !defined(MBEDTLS_AES_128_BIT_MASKED)
 /*
  * Forward tables
  */
@@ -234,6 +250,8 @@ static const uint32_t FT3[256] = { FT };
 #endif /* !MBEDTLS_AES_FEWER_TABLES */
 
 #undef FT
+#endif //ifndef MBEDTLS_AES_128_BIT_MASKED
+
 
 #if !defined(MBEDTLS_AES_ONLY_ENCRYPT)
 /*
@@ -274,6 +292,7 @@ static const unsigned char RSb[256] =
     0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26,
     0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
 };
+
 #endif /* !MBEDTLS_AES_ONLY_ENCRYPT */
 
 /*
@@ -386,7 +405,9 @@ static const uint32_t RCON[10] =
  * Forward S-box & tables
  */
 static unsigned char FSb[256];
+#if !defined(MBEDTLS_AES_128_BIT_MASKED)
 static uint32_t FT0[256];
+#endif
 #if !defined(MBEDTLS_AES_FEWER_TABLES)
 static uint32_t FT1[256];
 static uint32_t FT2[256];
@@ -398,6 +419,7 @@ static uint32_t FT3[256];
  */
 #if !defined(MBEDTLS_AES_ONLY_ENCRYPT)
 static unsigned char RSb[256];
+
 static uint32_t RT0[256];
 #if !defined(MBEDTLS_AES_FEWER_TABLES)
 static uint32_t RT1[256];
@@ -414,15 +436,20 @@ static uint32_t RCON[10];
 /*
  * Tables generation code
  */
-#define ROTL8(x) ( ( (x) << 8 ) & 0xFFFFFFFF ) | ( (x) >> 24 )
 #define XTIME(x) ( ( (x) << 1 ) ^ ( ( (x) & 0x80 ) ? 0x1B : 0x00 ) )
+#if !defined(MBEDTLS_AES_128_BIT_MASKED)
+#define ROTL8(x) ( ( (x) << 8 ) & 0xFFFFFFFF ) | ( (x) >> 24 )
 #define MUL(x,y) ( ( (x) && (y) ) ? pow[(log[(x)]+log[(y)]) % 255] : 0 )
+#endif
 
 static int aes_init_done = 0;
 
 static void aes_gen_tables( void )
 {
-    int i, x, y, z;
+    int i, x, y;
+#if !defined(MBEDTLS_AES_128_BIT_MASKED)
+    int z;
+#endif
     int pow[256];
     int log[256];
 
@@ -468,7 +495,7 @@ static void aes_gen_tables( void )
         RSb[x] = (unsigned char) i;
 #endif
     }
-
+#if !defined(MBEDTLS_AES_128_BIT_MASKED)
     /*
      * generate the forward and reverse tables
      */
@@ -504,6 +531,8 @@ static void aes_gen_tables( void )
 #endif /* !MBEDTLS_AES_FEWER_TABLES */
 #endif /* !MBEDTLS_AES_ONLY_ENCRYPT */
     }
+
+#endif //MBEDTLS_AES_128_BIT_MASKED
 }
 
 #undef ROTL8
@@ -611,6 +640,7 @@ static int aes_sca_cm_data_randomize( uint8_t *tbl, int tbl_len )
 }
 #endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
 
+#if !defined(MBEDTLS_AES_128_BIT_MASKED)
 #if defined(MBEDTLS_AES_FEWER_TABLES)
 
 #define ROTL8(x)  ( (uint32_t)( ( x ) <<  8 ) + (uint32_t)( ( x ) >> 24 ) )
@@ -640,6 +670,7 @@ static int aes_sca_cm_data_randomize( uint8_t *tbl, int tbl_len )
 #define AES_FT3(idx) FT3[idx]
 
 #endif /* MBEDTLS_AES_FEWER_TABLES */
+#endif
 
 void mbedtls_aes_init( mbedtls_aes_context *ctx )
 {
@@ -690,6 +721,8 @@ static void mbedtls_generate_fake_key( unsigned int keybits, mbedtls_aes_context
 /*
  * AES key schedule (encryption)
  */
+
+
 #if !defined(MBEDTLS_AES_SETKEY_ENC_ALT)
 int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
                     unsigned int keybits )
@@ -700,7 +733,6 @@ int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
     volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     uint32_t *RK;
     uint32_t offset = 0;
-
     AES_VALIDATE_RET( ctx != NULL );
     AES_VALIDATE_RET( key != NULL );
     (void) ret;
@@ -731,6 +763,7 @@ int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
         ctx->rk = RK = MBEDTLS_PADLOCK_ALIGN16( ctx->buf );
     else
 #endif
+
     ctx->rk = RK = ctx->buf;
 #if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
     mbedtls_generate_fake_key( keybits, ctx );
@@ -761,7 +794,6 @@ int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
     switch( ctx->nr )
     {
         case 10:
-
             for( i = 0; i < 10; i++, RK += 4 )
             {
                 RK[4]  = RK[0] ^ RCON[i] ^
@@ -1026,6 +1058,263 @@ int mbedtls_aes_xts_setkey_dec( mbedtls_aes_xts_context *ctx,
 #if !defined(MBEDTLS_AES_ENCRYPT_ALT)
 
 #if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
+
+#if defined(MBEDTLS_AES_128_BIT_MASKED)
+
+static uint8_t xtime(uint8_t x)
+{
+  return ((x << 1) ^ (((x >> 7) & 1) * 0x1b));
+}
+
+static int sub_bytes_masked(uint32_t *data, uint8_t sbox_masked[256])
+{
+	volatile unsigned int i;
+
+	for (i = 0; i < 4; i++) {
+        data[i] = ( (uint32_t) sbox_masked[ ( data[i]       ) & 0xFF ]       ) ^
+                  ( (uint32_t) sbox_masked[ ( data[i]  >> 8 ) & 0xFF ] <<  8 ) ^
+                  ( (uint32_t) sbox_masked[ ( data[i] >> 16 ) & 0xFF ] << 16 ) ^
+                  ( (uint32_t) sbox_masked[ ( data[i] >> 24 ) & 0xFF ] << 24 );
+    }
+
+    if (i == 4){
+        return 0;
+    }
+
+    return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+static int mix_columns(uint8_t *s)
+{
+  masked_state_t *state = (masked_state_t *) s;
+  volatile unsigned int i = 0;
+  uint8_t Tmp, Tm, t;
+
+  for (i = 0; i < 4; ++i)
+  {
+    t = (*state)[i][0];
+    Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3];
+    Tm = (*state)[i][0] ^ (*state)[i][1];
+    Tm = xtime(Tm);
+    (*state)[i][0] ^= Tm ^ Tmp;
+    Tm = (*state)[i][1] ^ (*state)[i][2];
+    Tm = xtime(Tm);
+    (*state)[i][1] ^= Tm ^ Tmp;
+    Tm = (*state)[i][2] ^ (*state)[i][3];
+    Tm = xtime(Tm);
+    (*state)[i][2] ^= Tm ^ Tmp;
+    Tm = (*state)[i][3] ^ t;
+    Tm = xtime(Tm);
+    (*state)[i][3] ^= Tm ^ Tmp;
+  }
+
+  if (i == 4) {
+        return 0;
+  }
+
+  return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+static void shift_rows(uint8_t *s)
+{
+   uint8_t temp;
+   masked_state_t *state = (masked_state_t *) s;
+  // Rotate first row 1 columns to left
+  temp = (*state)[0][1];
+  (*state)[0][1] = (*state)[1][1];
+  (*state)[1][1] = (*state)[2][1];
+  (*state)[2][1] = (*state)[3][1];
+  (*state)[3][1] = temp;
+
+  // Rotate second row 2 columns to left
+  temp = (*state)[0][2];
+  (*state)[0][2] = (*state)[2][2];
+  (*state)[2][2] = temp;
+
+  temp = (*state)[1][2];
+  (*state)[1][2] = (*state)[3][2];
+  (*state)[3][2] = temp;
+
+  // Rotate third row 3 columns to left
+  temp = (*state)[0][3];
+  (*state)[0][3] = (*state)[3][3];
+  (*state)[3][3] = (*state)[2][3];
+  (*state)[2][3] = (*state)[1][3];
+  (*state)[1][3] = temp;
+
+}
+
+#define mul_02(num) ( (num << 1) ^ (0x11b & -(num >> 7)) )
+#define mul_03(num) ( mul_02(num) ^ num )
+
+static void calcMixColmask(uint32_t mask[10])
+{ 
+  mask[6] = mul_02(mask[0]) ^ mul_03(mask[1]) ^ mask[2]         ^ mask[3];
+  mask[7] = mask[0]         ^ mul_02(mask[1]) ^ mul_03(mask[2]) ^ mask[3];
+  mask[8] = mask[0]         ^ mask[1]         ^ mul_02(mask[2]) ^ mul_03(mask[3]);
+  mask[9] = mul_03(mask[0]) ^ mask[1]         ^ mask[2]         ^ mul_02(mask[3]);
+}
+
+//Calculate the the invSbox to change from Mask m to Mask m'
+static int calcSboxMasked(uint32_t mask[10], uint8_t sbox_masked[256])
+{
+  volatile unsigned int i = 0;
+
+  for ( i = 0; i < 256; i++ )
+  {
+    sbox_masked[i ^ mask[4]] = FSb[i] ^ mask[5];
+  }
+  if (i == 256) {
+        return 0;
+  }
+
+  return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+static int remask(uint32_t *data, uint32_t m1, uint32_t m2, uint32_t m3, uint32_t m4, uint32_t m5, uint32_t m6, uint32_t m7, uint32_t m8)
+{
+
+  volatile unsigned int i = 0;
+ 
+  for ( i = 0; i < 4; i++)
+  {
+    data[i] = data[i] ^ ( (m1^m5)       );
+    data[i] = data[i] ^ ( (m2^m6) << 8  );
+    data[i] = data[i] ^ ( (m3^m7) << 16 );
+    data[i] = data[i] ^ ( (m4^m8) << 24 );
+  }
+
+  if (i == 4) {
+        return 0;
+  }
+
+  return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+
+static int init_masking_encrypt(const uint8_t *rk, uint8_t *rk_masked, uint32_t mask[10], uint8_t sbox_masked[256] )
+{
+  volatile int flow_control = 0;
+  unsigned int i = 0;
+
+  mbedtls_platform_memcpy(rk_masked, rk, AES_128_EXPANDED_KEY_SIZE_IN_WORDS*4);
+
+
+  //Randomly generate the masks: m1 m2 m3 m4 m m'
+  for (i = 0; i < 6; i++)
+  {
+    mask[i] = mbedtls_platform_random_in_range( 0xFF );
+    flow_control++;
+  }
+
+  //Calculate m1',m2',m3',m4'
+  calcMixColmask(mask);
+  flow_control++;
+
+  //Calculate the masked Sbox
+  if (calcSboxMasked(mask, sbox_masked) == 0){
+      flow_control++;   
+  }
+  
+#define MASK_INIT_CONTROL 19
+  //Init masked key
+  if (remask(  (uint32_t *)&rk_masked[(Nr * Nb * 4)], 0, 0, 0, 0, mask[5], mask[5], mask[5], mask[5]) == 0) {
+      flow_control++;
+  }
+  
+
+  // Mask change from M1',M2',M3',M4' to M
+  for (i = 0; i < Nr; i++)
+  {
+      if ( remask( (uint32_t *)&rk_masked[( i * Nb * 4 )], mask[6], mask[7], mask[8], mask[9], mask[4], mask[4], mask[4], mask[4]) == 0 )
+          flow_control++;
+  }
+  
+  if( flow_control == MASK_INIT_CONTROL ) {
+      mbedtls_platform_random_delay();
+      if( flow_control == MASK_INIT_CONTROL ) {
+        return MASK_INIT_CONTROL;
+      }   
+  }
+  
+  return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+static int add_rk_masked(uint32_t round, uint32_t *data, const uint32_t * rk_masked)
+{
+  volatile unsigned int i;
+  unsigned int offset = round*4;
+  for( i = 0; i < 4; i++ )
+  {
+      data[i] ^= rk_masked[offset + i] ;
+  }
+
+  if (i == 4) {
+        return 0;
+  }
+  return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+
+static int aes_masked_round(uint32_t *data, uint32_t *key, uint32_t round, uint32_t mask[10], uint8_t sbox_masked[256])
+{
+    volatile uint32_t flow_control = 0;
+
+// Mask changes from M to M'
+    if ( sub_bytes_masked(data, sbox_masked) == 0 )
+        flow_control++;
+
+    //No impact on mask
+    shift_rows((uint8_t *)data);
+
+    //Change mask from M' to
+    // M1 for first row
+    // M2 for second row
+    // M3 for third row
+    // M4 for fourth row
+    if ( remask(data, mask[0], mask[1], mask[2], mask[3], mask[5], mask[5], mask[5], mask[5]) == 0)
+        flow_control++;
+
+    // Masks change from M1,M2,M3,M4 to M1',M2',M3',M4'
+    if ( mix_columns((uint8_t *)data) == 0)
+        flow_control++;
+
+    // Add the First round key to the state before starting the rounds.
+    // Masks change from M1',M2',M3',M4' to M
+    if ( add_rk_masked(round,data, key) == 0 )
+        flow_control++;
+    
+    if ( flow_control == 4 )
+        return 0;
+
+    return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+
+static int aes_masked_round_final( uint32_t *data, uint32_t *key, uint8_t sbox_masked[256] )
+{
+    volatile uint32_t flow_control = 0;
+
+    if ( sub_bytes_masked(data, sbox_masked) == 0 )
+        flow_control++;
+    
+    shift_rows((uint8_t *)data);        
+
+    // Mask are removed by the last addroundkey
+    // From M' to 0
+    if( add_rk_masked(Nr, data, key) == 0)
+        flow_control++;
+    
+    if ( flow_control == 2 )
+        return 0;
+
+    return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+}
+#define MASKING_FLOW_CONTORL (MASK_INIT_CONTROL + 2) //2 comes from initial data remask of real and fake data
+
+#else // end of MBEDTLS_AES_128_BIT_MASKED
+
+#define MASKING_FLOW_CONTORL 0
+
 static uint32_t *aes_fround( uint32_t *R,
     uint32_t *X0, uint32_t *X1, uint32_t *X2, uint32_t *X3,
     uint32_t Y0, uint32_t Y1, uint32_t Y2, uint32_t Y3 )
@@ -1053,10 +1342,12 @@ static uint32_t *aes_fround( uint32_t *R,
     return R;
 }
 
+
 static void aes_fround_final( uint32_t *R,
     uint32_t *X0, uint32_t *X1, uint32_t *X2, uint32_t *X3,
     uint32_t Y0, uint32_t Y1, uint32_t Y2, uint32_t Y3 )
 {
+
     *X0 = *R++ ^ ( (uint32_t) FSb[ ( (Y0)       ) & 0xFF ]       ) ^
                  ( (uint32_t) FSb[ ( (Y1) >>  8 ) & 0xFF ] <<  8 ) ^
                  ( (uint32_t) FSb[ ( (Y2) >> 16 ) & 0xFF ] << 16 ) ^
@@ -1077,22 +1368,30 @@ static void aes_fround_final( uint32_t *R,
                  ( (uint32_t) FSb[ ( (Y1) >> 16 ) & 0xFF ] << 16 ) ^
                  ( (uint32_t) FSb[ ( (Y2) >> 24 ) & 0xFF ] << 24 );
 }
+#endif // MBEDTLS_AES_128_BIT_MASKED
+
  
 int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
                                   const unsigned char input[16],
                                   unsigned char output[16] )
 {
     int i, tindex, offset, stop_mark, dummy_rounds;
-    aes_r_data_t aes_data_real;         // real data
+    aes_r_data_t aes_data_real = {0};         // real data
-    aes_r_data_t aes_data_fake;         // fake data
+    aes_r_data_t aes_data_fake = {0};         // fake data
     aes_r_data_t *aes_data_ptr;         // pointer to real or fake data
-    aes_r_data_t *aes_data_table[2];    // pointers to real and fake data
+    aes_r_data_t *aes_data_table[2] = {0};    // pointers to real and fake data
     int round_ctrl_table_len = ctx->nr + 2 + AES_SCA_CM_ROUNDS;
-    volatile int flow_control;
+    volatile int flow_control = 0;
     // control bytes for AES calculation rounds,
     // reserve based on max rounds + dummy rounds + 2 (for initial key addition)
     uint8_t round_ctrl_table[( 14 + AES_SCA_CM_ROUNDS + 2 )];
 
+#if defined MBEDTLS_AES_128_BIT_MASKED
+    uint32_t rk_masked[AES_128_EXPANDED_KEY_SIZE_IN_WORDS] = {0};
+    static uint8_t sbox_masked[256] = {0};
+    uint32_t mask[10] = {0};
+#endif
+
 #if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
     unsigned key_bytes = 0;
     uint32_t check_hash = 0;
@@ -1108,7 +1407,14 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
     check_hash = mbedtls_hash( ctx->rk, key_bytes );
 #endif
 
+#if defined (MBEDTLS_AES_128_BIT_MASKED)
+    //Flow control should be MASK_INIT_CONTROL and it will be checked as a part last flow control verification 
+    flow_control = init_masking_encrypt((uint8_t*)ctx->rk, (uint8_t*)rk_masked, mask, sbox_masked);
+    aes_data_real.rk_ptr = &rk_masked[0];
+#else
     aes_data_real.rk_ptr = ctx->rk;    
+#endif    
+    
     aes_data_fake.rk_ptr = ctx->frk;
 
     aes_data_table[0] = &aes_data_real;
@@ -1117,7 +1423,7 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
     // Get AES calculation control bytes
     dummy_rounds = aes_sca_cm_data_randomize( round_ctrl_table,
                                               round_ctrl_table_len );
-    flow_control = dummy_rounds;
+    flow_control += dummy_rounds;
 
     // SCA countermeasure, safely clear the aes_data_real.xy_values
     mbedtls_platform_memset( aes_data_real.xy_values, 0, 16 );
@@ -1134,6 +1440,16 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
         flow_control++;
     } while( ( i = ( i + 1 ) % 4 ) != offset );
 
+#if defined (MBEDTLS_AES_128_BIT_MASKED)    
+    //Plain text masked with m1',m2',m3',m4'
+    if (remask( &aes_data_real.xy_values[0], mask[6], mask[7], mask[8], mask[9], 0, 0, 0, 0) == 0)
+        flow_control++;
+
+    if (remask( &aes_data_fake.xy_values[0], mask[6], mask[7], mask[8], mask[9], 0, 0, 0, 0) == 0)
+        flow_control++;    
+    
+#endif
+
     tindex = 0;
     do
     {
@@ -1142,14 +1458,22 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
         stop_mark = round_ctrl_table[tindex] & 0x03;
         
         // initial round key addition
+#if defined (MBEDTLS_AES_128_BIT_MASKED)
+        if ( add_rk_masked(0, &aes_data_ptr->xy_values[0], aes_data_ptr->rk_ptr) == 0)
+            flow_control++;
+        aes_data_ptr->round = 1;
+#else
         for( i = 0; i < 4; i++ )
         {
             aes_data_ptr->xy_values[i] ^= *aes_data_ptr->rk_ptr++;
         }
-        tindex++;
         flow_control++;
+#endif
+
+        tindex++;
     } while( stop_mark == 0 );
  
+
     // Calculate AES rounds (9, 11 or 13 rounds) + dummy rounds
     do
     {
@@ -1157,7 +1481,12 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
         aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
         offset = round_ctrl_table[tindex] & 0x04;
         stop_mark = round_ctrl_table[tindex] & 0x03;
-
+#if defined (MBEDTLS_AES_128_BIT_MASKED)
+        if (aes_masked_round( &aes_data_ptr->xy_values[0], aes_data_ptr->rk_ptr,
+                               aes_data_ptr->round, mask, sbox_masked) == 0)
+            flow_control++;
+        aes_data_ptr->round ++;
+#else
         aes_data_ptr->rk_ptr = aes_fround( aes_data_ptr->rk_ptr,
             &aes_data_ptr->xy_values[0 + offset],
             &aes_data_ptr->xy_values[1 + offset],
@@ -1167,8 +1496,10 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
             aes_data_ptr->xy_values[5 - offset],
             aes_data_ptr->xy_values[6 - offset],
             aes_data_ptr->xy_values[7 - offset] );
-        tindex++;
         flow_control++;
+#endif           
+        tindex++;
+        
     } while( stop_mark == 0 );
 
     // Calculate final AES round + dummy rounds
@@ -1176,6 +1507,13 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
     {
         aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
         stop_mark = round_ctrl_table[tindex] & 0x03;
+#if defined (MBEDTLS_AES_128_BIT_MASKED)
+        if ( aes_masked_round_final( &aes_data_ptr->xy_values[0],
+                                     aes_data_ptr->rk_ptr, sbox_masked ) == 0)
+            flow_control++;
+        //Cleanup the masked key        
+        mbedtls_platform_memset(rk_masked, 0, sizeof(rk_masked));                   
+#else
         aes_fround_final( aes_data_ptr->rk_ptr,
             &aes_data_ptr->xy_values[0],
             &aes_data_ptr->xy_values[1],
@@ -1186,9 +1524,11 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
             aes_data_ptr->xy_values[6],
             aes_data_ptr->xy_values[7] );
         flow_control++;
+#endif
         tindex++;
     } while( stop_mark == 0 );
 
+
     // SCA countermeasure, safely clear the output
     mbedtls_platform_memset( output, 0, 16 );
 
@@ -1202,8 +1542,11 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
         flow_control++;
     } while( ( i = ( i + 1 ) % 4 ) != offset );
 
+#if defined (MBEDTLS_AES_128_BIT_MASKED)    
+    mbedtls_platform_memset(rk_masked, 0, sizeof(rk_masked));
+#endif    
     /* Double negation is used to silence an "extraneous parentheses" warning */
-    if( ! ( flow_control != tindex + dummy_rounds + 8 )
+    if( ! ( flow_control != tindex + dummy_rounds + MASKING_FLOW_CONTORL + 8 )
 #if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
          && check_hash == ctx->hash
 #endif
@@ -1220,6 +1563,14 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
     
     // Clear the output in case of a FI
     mbedtls_platform_memset( output, 0, 16 );
+    mbedtls_platform_memset( aes_data_real.xy_values, 0, 16 );
+    mbedtls_platform_memset (aes_data_table, 0, sizeof(aes_data_table));
+#if defined (MBEDTLS_AES_128_BIT_MASKED)
+    //Clear masked key, masked sbox and mask in case of a FI
+    mbedtls_platform_memset(rk_masked, 0, sizeof(rk_masked));
+    mbedtls_platform_memset(mask, 0, sizeof(mask));
+    mbedtls_platform_memset(sbox_masked, 0, sizeof(sbox_masked));
+#endif
     return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
 }
 
@@ -1334,7 +1685,7 @@ void mbedtls_aes_encrypt( mbedtls_aes_context *ctx,
 #if !defined(MBEDTLS_AES_ONLY_ENCRYPT)
 
 #if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
-static uint32_t *aes_rround( uint32_t *R,
+static uint32_t *aes_fround( uint32_t *R,
     uint32_t *X0, uint32_t *X1, uint32_t *X2, uint32_t *X3,
     uint32_t Y0, uint32_t Y1, uint32_t Y2, uint32_t Y3 )
 {
@@ -1621,9 +1972,9 @@ int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
 
     return( 0 );
 }
+#endif /* !MBEDTLS_AES_ONLY_ENCRYPT */
 #endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
 
-#endif /* !MBEDTLS_AES_ONLY_ENCRYPT */
 #endif /* !MBEDTLS_AES_DECRYPT_ALT */
 
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)

library/version_features.c

@@ -276,6 +276,9 @@ static const char *features[] = {
 #if defined(MBEDTLS_FI_COUNTERMEASURES)
     "MBEDTLS_FI_COUNTERMEASURES",
 #endif /* MBEDTLS_FI_COUNTERMEASURES */
+#if defined(MBEDTLS_AES_128_BIT_MASKED)
+    "MBEDTLS_AES_128_BIT_MASKED",
+#endif /* MBEDTLS_AES_128_BIT_MASKED */
 #if defined(MBEDTLS_CAMELLIA_SMALL_MEMORY)
     "MBEDTLS_CAMELLIA_SMALL_MEMORY",
 #endif /* MBEDTLS_CAMELLIA_SMALL_MEMORY */

programs/ssl/query_config.c

@@ -770,6 +770,14 @@ int query_config( const char *config )
     }
 #endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
 
+#if defined(MBEDTLS_AES_128_BIT_MASKED)
+    if( strcmp( "MBEDTLS_AES_128_BIT_MASKED", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_AES_128_BIT_MASKED );
+        return( 0 );
+    }
+#endif /* MBEDTLS_AES_128_BIT_MASKED */
+
 #if defined(MBEDTLS_FI_COUNTERMEASURES)
     if( strcmp( "MBEDTLS_FI_COUNTERMEASURES", config ) == 0 )
     {

scripts/config.pl

@@ -60,6 +60,7 @@
 #   MBEDTLS_SSL_TRANSFORM_OPTIMIZE_CIPHERS
 #   MBEDTLS_VALIDATE_SSL_KEYS_INTEGRITY
 #   MBEDTLS_OPTIMIZE_TINYCRYPT_ASM
+#   MBEDTLS_AES_128_BIT_MASKED
 #   and any symbol beginning _ALT
 #
 # The baremetal configuration excludes options that require a library or
@@ -146,6 +147,7 @@ MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
 MBEDTLS_SSL_TRANSFORM_OPTIMIZE_CIPHERS
 MBEDTLS_VALIDATE_SSL_KEYS_INTEGRITY
 MBEDTLS_OPTIMIZE_TINYCRYPT_ASM
+MBEDTLS_AES_128_BIT_MASKED
 _ALT\s*$
 );