diff --git a/library/sha1.c b/library/sha1.c
index 65841ee..7e6981d 100644
--- a/library/sha1.c
+++ b/library/sha1.c
@@ -147,32 +147,37 @@
 int mbedtls_internal_sha1_process( mbedtls_sha1_context *ctx,
                                    const unsigned char data[64] )
 {
-    uint32_t temp, W[16], A, B, C, D, E;
+    struct
+    {
+        uint32_t temp, W[16], A, B, C, D, E;
+    } local;
 
-    GET_UINT32_BE( W[ 0], data,  0 );
-    GET_UINT32_BE( W[ 1], data,  4 );
-    GET_UINT32_BE( W[ 2], data,  8 );
-    GET_UINT32_BE( W[ 3], data, 12 );
-    GET_UINT32_BE( W[ 4], data, 16 );
-    GET_UINT32_BE( W[ 5], data, 20 );
-    GET_UINT32_BE( W[ 6], data, 24 );
-    GET_UINT32_BE( W[ 7], data, 28 );
-    GET_UINT32_BE( W[ 8], data, 32 );
-    GET_UINT32_BE( W[ 9], data, 36 );
-    GET_UINT32_BE( W[10], data, 40 );
-    GET_UINT32_BE( W[11], data, 44 );
-    GET_UINT32_BE( W[12], data, 48 );
-    GET_UINT32_BE( W[13], data, 52 );
-    GET_UINT32_BE( W[14], data, 56 );
-    GET_UINT32_BE( W[15], data, 60 );
+    GET_UINT32_BE( local.W[ 0], data,  0 );
+    GET_UINT32_BE( local.W[ 1], data,  4 );
+    GET_UINT32_BE( local.W[ 2], data,  8 );
+    GET_UINT32_BE( local.W[ 3], data, 12 );
+    GET_UINT32_BE( local.W[ 4], data, 16 );
+    GET_UINT32_BE( local.W[ 5], data, 20 );
+    GET_UINT32_BE( local.W[ 6], data, 24 );
+    GET_UINT32_BE( local.W[ 7], data, 28 );
+    GET_UINT32_BE( local.W[ 8], data, 32 );
+    GET_UINT32_BE( local.W[ 9], data, 36 );
+    GET_UINT32_BE( local.W[10], data, 40 );
+    GET_UINT32_BE( local.W[11], data, 44 );
+    GET_UINT32_BE( local.W[12], data, 48 );
+    GET_UINT32_BE( local.W[13], data, 52 );
+    GET_UINT32_BE( local.W[14], data, 56 );
+    GET_UINT32_BE( local.W[15], data, 60 );
 
 #define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))
 
 #define R(t)                                            \
 (                                                       \
-    temp = W[( t -  3 ) & 0x0F] ^ W[( t - 8 ) & 0x0F] ^ \
-           W[( t - 14 ) & 0x0F] ^ W[  t       & 0x0F],  \
-    ( W[t & 0x0F] = S(temp,1) )                         \
+    local.temp = local.W[( t -  3 ) & 0x0F] ^           \
+                 local.W[( t -  8 ) & 0x0F] ^           \
+                 local.W[( t - 14 ) & 0x0F] ^           \
+                 local.W[  t        & 0x0F],            \
+    ( local.W[t & 0x0F] = S(local.temp,1) )             \
 )
 
 #define P(a,b,c,d,e,x)                                  \
@@ -180,35 +185,35 @@
     e += S(a,5) + F(b,c,d) + K + x; b = S(b,30);        \
 }
 
-    A = ctx->state[0];
-    B = ctx->state[1];
-    C = ctx->state[2];
-    D = ctx->state[3];
-    E = ctx->state[4];
+    local.A = ctx->state[0];
+    local.B = ctx->state[1];
+    local.C = ctx->state[2];
+    local.D = ctx->state[3];
+    local.E = ctx->state[4];
 
 #define F(x,y,z) (z ^ (x & (y ^ z)))
 #define K 0x5A827999
 
-    P( A, B, C, D, E, W[0]  );
-    P( E, A, B, C, D, W[1]  );
-    P( D, E, A, B, C, W[2]  );
-    P( C, D, E, A, B, W[3]  );
-    P( B, C, D, E, A, W[4]  );
-    P( A, B, C, D, E, W[5]  );
-    P( E, A, B, C, D, W[6]  );
-    P( D, E, A, B, C, W[7]  );
-    P( C, D, E, A, B, W[8]  );
-    P( B, C, D, E, A, W[9]  );
-    P( A, B, C, D, E, W[10] );
-    P( E, A, B, C, D, W[11] );
-    P( D, E, A, B, C, W[12] );
-    P( C, D, E, A, B, W[13] );
-    P( B, C, D, E, A, W[14] );
-    P( A, B, C, D, E, W[15] );
-    P( E, A, B, C, D, R(16) );
-    P( D, E, A, B, C, R(17) );
-    P( C, D, E, A, B, R(18) );
-    P( B, C, D, E, A, R(19) );
+    P( local.A, local.B, local.C, local.D, local.E, local.W[0]  );
+    P( local.E, local.A, local.B, local.C, local.D, local.W[1]  );
+    P( local.D, local.E, local.A, local.B, local.C, local.W[2]  );
+    P( local.C, local.D, local.E, local.A, local.B, local.W[3]  );
+    P( local.B, local.C, local.D, local.E, local.A, local.W[4]  );
+    P( local.A, local.B, local.C, local.D, local.E, local.W[5]  );
+    P( local.E, local.A, local.B, local.C, local.D, local.W[6]  );
+    P( local.D, local.E, local.A, local.B, local.C, local.W[7]  );
+    P( local.C, local.D, local.E, local.A, local.B, local.W[8]  );
+    P( local.B, local.C, local.D, local.E, local.A, local.W[9]  );
+    P( local.A, local.B, local.C, local.D, local.E, local.W[10] );
+    P( local.E, local.A, local.B, local.C, local.D, local.W[11] );
+    P( local.D, local.E, local.A, local.B, local.C, local.W[12] );
+    P( local.C, local.D, local.E, local.A, local.B, local.W[13] );
+    P( local.B, local.C, local.D, local.E, local.A, local.W[14] );
+    P( local.A, local.B, local.C, local.D, local.E, local.W[15] );
+    P( local.E, local.A, local.B, local.C, local.D, R(16) );
+    P( local.D, local.E, local.A, local.B, local.C, R(17) );
+    P( local.C, local.D, local.E, local.A, local.B, R(18) );
+    P( local.B, local.C, local.D, local.E, local.A, R(19) );
 
 #undef K
 #undef F
@@ -216,26 +221,26 @@
 #define F(x,y,z) (x ^ y ^ z)
 #define K 0x6ED9EBA1
 
-    P( A, B, C, D, E, R(20) );
-    P( E, A, B, C, D, R(21) );
-    P( D, E, A, B, C, R(22) );
-    P( C, D, E, A, B, R(23) );
-    P( B, C, D, E, A, R(24) );
-    P( A, B, C, D, E, R(25) );
-    P( E, A, B, C, D, R(26) );
-    P( D, E, A, B, C, R(27) );
-    P( C, D, E, A, B, R(28) );
-    P( B, C, D, E, A, R(29) );
-    P( A, B, C, D, E, R(30) );
-    P( E, A, B, C, D, R(31) );
-    P( D, E, A, B, C, R(32) );
-    P( C, D, E, A, B, R(33) );
-    P( B, C, D, E, A, R(34) );
-    P( A, B, C, D, E, R(35) );
-    P( E, A, B, C, D, R(36) );
-    P( D, E, A, B, C, R(37) );
-    P( C, D, E, A, B, R(38) );
-    P( B, C, D, E, A, R(39) );
+    P( local.A, local.B, local.C, local.D, local.E, R(20) );
+    P( local.E, local.A, local.B, local.C, local.D, R(21) );
+    P( local.D, local.E, local.A, local.B, local.C, R(22) );
+    P( local.C, local.D, local.E, local.A, local.B, R(23) );
+    P( local.B, local.C, local.D, local.E, local.A, R(24) );
+    P( local.A, local.B, local.C, local.D, local.E, R(25) );
+    P( local.E, local.A, local.B, local.C, local.D, R(26) );
+    P( local.D, local.E, local.A, local.B, local.C, R(27) );
+    P( local.C, local.D, local.E, local.A, local.B, R(28) );
+    P( local.B, local.C, local.D, local.E, local.A, R(29) );
+    P( local.A, local.B, local.C, local.D, local.E, R(30) );
+    P( local.E, local.A, local.B, local.C, local.D, R(31) );
+    P( local.D, local.E, local.A, local.B, local.C, R(32) );
+    P( local.C, local.D, local.E, local.A, local.B, R(33) );
+    P( local.B, local.C, local.D, local.E, local.A, R(34) );
+    P( local.A, local.B, local.C, local.D, local.E, R(35) );
+    P( local.E, local.A, local.B, local.C, local.D, R(36) );
+    P( local.D, local.E, local.A, local.B, local.C, R(37) );
+    P( local.C, local.D, local.E, local.A, local.B, R(38) );
+    P( local.B, local.C, local.D, local.E, local.A, R(39) );
 
 #undef K
 #undef F
@@ -243,26 +248,26 @@
 #define F(x,y,z) ((x & y) | (z & (x | y)))
 #define K 0x8F1BBCDC
 
-    P( A, B, C, D, E, R(40) );
-    P( E, A, B, C, D, R(41) );
-    P( D, E, A, B, C, R(42) );
-    P( C, D, E, A, B, R(43) );
-    P( B, C, D, E, A, R(44) );
-    P( A, B, C, D, E, R(45) );
-    P( E, A, B, C, D, R(46) );
-    P( D, E, A, B, C, R(47) );
-    P( C, D, E, A, B, R(48) );
-    P( B, C, D, E, A, R(49) );
-    P( A, B, C, D, E, R(50) );
-    P( E, A, B, C, D, R(51) );
-    P( D, E, A, B, C, R(52) );
-    P( C, D, E, A, B, R(53) );
-    P( B, C, D, E, A, R(54) );
-    P( A, B, C, D, E, R(55) );
-    P( E, A, B, C, D, R(56) );
-    P( D, E, A, B, C, R(57) );
-    P( C, D, E, A, B, R(58) );
-    P( B, C, D, E, A, R(59) );
+    P( local.A, local.B, local.C, local.D, local.E, R(40) );
+    P( local.E, local.A, local.B, local.C, local.D, R(41) );
+    P( local.D, local.E, local.A, local.B, local.C, R(42) );
+    P( local.C, local.D, local.E, local.A, local.B, R(43) );
+    P( local.B, local.C, local.D, local.E, local.A, R(44) );
+    P( local.A, local.B, local.C, local.D, local.E, R(45) );
+    P( local.E, local.A, local.B, local.C, local.D, R(46) );
+    P( local.D, local.E, local.A, local.B, local.C, R(47) );
+    P( local.C, local.D, local.E, local.A, local.B, R(48) );
+    P( local.B, local.C, local.D, local.E, local.A, R(49) );
+    P( local.A, local.B, local.C, local.D, local.E, R(50) );
+    P( local.E, local.A, local.B, local.C, local.D, R(51) );
+    P( local.D, local.E, local.A, local.B, local.C, R(52) );
+    P( local.C, local.D, local.E, local.A, local.B, R(53) );
+    P( local.B, local.C, local.D, local.E, local.A, R(54) );
+    P( local.A, local.B, local.C, local.D, local.E, R(55) );
+    P( local.E, local.A, local.B, local.C, local.D, R(56) );
+    P( local.D, local.E, local.A, local.B, local.C, R(57) );
+    P( local.C, local.D, local.E, local.A, local.B, R(58) );
+    P( local.B, local.C, local.D, local.E, local.A, R(59) );
 
 #undef K
 #undef F
@@ -270,44 +275,38 @@
 #define F(x,y,z) (x ^ y ^ z)
 #define K 0xCA62C1D6
 
-    P( A, B, C, D, E, R(60) );
-    P( E, A, B, C, D, R(61) );
-    P( D, E, A, B, C, R(62) );
-    P( C, D, E, A, B, R(63) );
-    P( B, C, D, E, A, R(64) );
-    P( A, B, C, D, E, R(65) );
-    P( E, A, B, C, D, R(66) );
-    P( D, E, A, B, C, R(67) );
-    P( C, D, E, A, B, R(68) );
-    P( B, C, D, E, A, R(69) );
-    P( A, B, C, D, E, R(70) );
-    P( E, A, B, C, D, R(71) );
-    P( D, E, A, B, C, R(72) );
-    P( C, D, E, A, B, R(73) );
-    P( B, C, D, E, A, R(74) );
-    P( A, B, C, D, E, R(75) );
-    P( E, A, B, C, D, R(76) );
-    P( D, E, A, B, C, R(77) );
-    P( C, D, E, A, B, R(78) );
-    P( B, C, D, E, A, R(79) );
+    P( local.A, local.B, local.C, local.D, local.E, R(60) );
+    P( local.E, local.A, local.B, local.C, local.D, R(61) );
+    P( local.D, local.E, local.A, local.B, local.C, R(62) );
+    P( local.C, local.D, local.E, local.A, local.B, R(63) );
+    P( local.B, local.C, local.D, local.E, local.A, R(64) );
+    P( local.A, local.B, local.C, local.D, local.E, R(65) );
+    P( local.E, local.A, local.B, local.C, local.D, R(66) );
+    P( local.D, local.E, local.A, local.B, local.C, R(67) );
+    P( local.C, local.D, local.E, local.A, local.B, R(68) );
+    P( local.B, local.C, local.D, local.E, local.A, R(69) );
+    P( local.A, local.B, local.C, local.D, local.E, R(70) );
+    P( local.E, local.A, local.B, local.C, local.D, R(71) );
+    P( local.D, local.E, local.A, local.B, local.C, R(72) );
+    P( local.C, local.D, local.E, local.A, local.B, R(73) );
+    P( local.B, local.C, local.D, local.E, local.A, R(74) );
+    P( local.A, local.B, local.C, local.D, local.E, R(75) );
+    P( local.E, local.A, local.B, local.C, local.D, R(76) );
+    P( local.D, local.E, local.A, local.B, local.C, R(77) );
+    P( local.C, local.D, local.E, local.A, local.B, R(78) );
+    P( local.B, local.C, local.D, local.E, local.A, R(79) );
 
 #undef K
 #undef F
 
-    ctx->state[0] += A;
-    ctx->state[1] += B;
-    ctx->state[2] += C;
-    ctx->state[3] += D;
-    ctx->state[4] += E;
+    ctx->state[0] += local.A;
+    ctx->state[1] += local.B;
+    ctx->state[2] += local.C;
+    ctx->state[3] += local.D;
+    ctx->state[4] += local.E;
 
     /* Zeroise buffers and variables to clear sensitive data from memory. */
-    mbedtls_zeroize( &A, sizeof( A ) );
-    mbedtls_zeroize( &B, sizeof( B ) );
-    mbedtls_zeroize( &C, sizeof( C ) );
-    mbedtls_zeroize( &D, sizeof( D ) );
-    mbedtls_zeroize( &E, sizeof( E ) );
-    mbedtls_zeroize( &W, sizeof( W ) );
-    mbedtls_zeroize( &temp, sizeof( temp ) );
+    mbedtls_zeroize( &local, sizeof( local ) );
 
     return( 0 );
 }