diff --git a/library/md4.c b/library/md4.c
index 0416df3..5546202 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -115,31 +115,34 @@
 int mbedtls_internal_md4_process( mbedtls_md4_context *ctx,
                                   const unsigned char data[64] )
 {
-    uint32_t X[16], A, B, C, D;
+    struct
+    {
+        uint32_t X[16], A, B, C, D;
+    } local;
 
-    GET_UINT32_LE( X[ 0], data,  0 );
-    GET_UINT32_LE( X[ 1], data,  4 );
-    GET_UINT32_LE( X[ 2], data,  8 );
-    GET_UINT32_LE( X[ 3], data, 12 );
-    GET_UINT32_LE( X[ 4], data, 16 );
-    GET_UINT32_LE( X[ 5], data, 20 );
-    GET_UINT32_LE( X[ 6], data, 24 );
-    GET_UINT32_LE( X[ 7], data, 28 );
-    GET_UINT32_LE( X[ 8], data, 32 );
-    GET_UINT32_LE( X[ 9], data, 36 );
-    GET_UINT32_LE( X[10], data, 40 );
-    GET_UINT32_LE( X[11], data, 44 );
-    GET_UINT32_LE( X[12], data, 48 );
-    GET_UINT32_LE( X[13], data, 52 );
-    GET_UINT32_LE( X[14], data, 56 );
-    GET_UINT32_LE( X[15], data, 60 );
+    GET_UINT32_LE( local.X[ 0], data,  0 );
+    GET_UINT32_LE( local.X[ 1], data,  4 );
+    GET_UINT32_LE( local.X[ 2], data,  8 );
+    GET_UINT32_LE( local.X[ 3], data, 12 );
+    GET_UINT32_LE( local.X[ 4], data, 16 );
+    GET_UINT32_LE( local.X[ 5], data, 20 );
+    GET_UINT32_LE( local.X[ 6], data, 24 );
+    GET_UINT32_LE( local.X[ 7], data, 28 );
+    GET_UINT32_LE( local.X[ 8], data, 32 );
+    GET_UINT32_LE( local.X[ 9], data, 36 );
+    GET_UINT32_LE( local.X[10], data, 40 );
+    GET_UINT32_LE( local.X[11], data, 44 );
+    GET_UINT32_LE( local.X[12], data, 48 );
+    GET_UINT32_LE( local.X[13], data, 52 );
+    GET_UINT32_LE( local.X[14], data, 56 );
+    GET_UINT32_LE( local.X[15], data, 60 );
 
 #define S(x,n) (((x) << (n)) | (((x) & 0xFFFFFFFF) >> (32 - (n))))
 
-    A = ctx->state[0];
-    B = ctx->state[1];
-    C = ctx->state[2];
-    D = ctx->state[3];
+    local.A = ctx->state[0];
+    local.B = ctx->state[1];
+    local.C = ctx->state[2];
+    local.D = ctx->state[3];
 
 #define F(x, y, z) (((x) & (y)) | ((~(x)) & (z)))
 #define P(a,b,c,d,x,s)                           \
@@ -150,22 +153,22 @@
     } while( 0 )
 
 
-    P( A, B, C, D, X[ 0],  3 );
-    P( D, A, B, C, X[ 1],  7 );
-    P( C, D, A, B, X[ 2], 11 );
-    P( B, C, D, A, X[ 3], 19 );
-    P( A, B, C, D, X[ 4],  3 );
-    P( D, A, B, C, X[ 5],  7 );
-    P( C, D, A, B, X[ 6], 11 );
-    P( B, C, D, A, X[ 7], 19 );
-    P( A, B, C, D, X[ 8],  3 );
-    P( D, A, B, C, X[ 9],  7 );
-    P( C, D, A, B, X[10], 11 );
-    P( B, C, D, A, X[11], 19 );
-    P( A, B, C, D, X[12],  3 );
-    P( D, A, B, C, X[13],  7 );
-    P( C, D, A, B, X[14], 11 );
-    P( B, C, D, A, X[15], 19 );
+    P( local.A, local.B, local.C, local.D, local.X[ 0],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 1],  7 );
+    P( local.C, local.D, local.A, local.B, local.X[ 2], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[ 3], 19 );
+    P( local.A, local.B, local.C, local.D, local.X[ 4],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 5],  7 );
+    P( local.C, local.D, local.A, local.B, local.X[ 6], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[ 7], 19 );
+    P( local.A, local.B, local.C, local.D, local.X[ 8],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 9],  7 );
+    P( local.C, local.D, local.A, local.B, local.X[10], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[11], 19 );
+    P( local.A, local.B, local.C, local.D, local.X[12],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[13],  7 );
+    P( local.C, local.D, local.A, local.B, local.X[14], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[15], 19 );
 
 #undef P
 #undef F
@@ -178,22 +181,22 @@
         (a) = S((a),(s));                               \
     } while( 0 )
 
-    P( A, B, C, D, X[ 0],  3 );
-    P( D, A, B, C, X[ 4],  5 );
-    P( C, D, A, B, X[ 8],  9 );
-    P( B, C, D, A, X[12], 13 );
-    P( A, B, C, D, X[ 1],  3 );
-    P( D, A, B, C, X[ 5],  5 );
-    P( C, D, A, B, X[ 9],  9 );
-    P( B, C, D, A, X[13], 13 );
-    P( A, B, C, D, X[ 2],  3 );
-    P( D, A, B, C, X[ 6],  5 );
-    P( C, D, A, B, X[10],  9 );
-    P( B, C, D, A, X[14], 13 );
-    P( A, B, C, D, X[ 3],  3 );
-    P( D, A, B, C, X[ 7],  5 );
-    P( C, D, A, B, X[11],  9 );
-    P( B, C, D, A, X[15], 13 );
+    P( local.A, local.B, local.C, local.D, local.X[ 0],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 4],  5 );
+    P( local.C, local.D, local.A, local.B, local.X[ 8],  9 );
+    P( local.B, local.C, local.D, local.A, local.X[12], 13 );
+    P( local.A, local.B, local.C, local.D, local.X[ 1],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 5],  5 );
+    P( local.C, local.D, local.A, local.B, local.X[ 9],  9 );
+    P( local.B, local.C, local.D, local.A, local.X[13], 13 );
+    P( local.A, local.B, local.C, local.D, local.X[ 2],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 6],  5 );
+    P( local.C, local.D, local.A, local.B, local.X[10],  9 );
+    P( local.B, local.C, local.D, local.A, local.X[14], 13 );
+    P( local.A, local.B, local.C, local.D, local.X[ 3],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 7],  5 );
+    P( local.C, local.D, local.A, local.B, local.X[11],  9 );
+    P( local.B, local.C, local.D, local.A, local.X[15], 13 );
 
 #undef P
 #undef F
@@ -206,37 +209,33 @@
         (a) = S((a),(s));                               \
     } while( 0 )
 
-    P( A, B, C, D, X[ 0],  3 );
-    P( D, A, B, C, X[ 8],  9 );
-    P( C, D, A, B, X[ 4], 11 );
-    P( B, C, D, A, X[12], 15 );
-    P( A, B, C, D, X[ 2],  3 );
-    P( D, A, B, C, X[10],  9 );
-    P( C, D, A, B, X[ 6], 11 );
-    P( B, C, D, A, X[14], 15 );
-    P( A, B, C, D, X[ 1],  3 );
-    P( D, A, B, C, X[ 9],  9 );
-    P( C, D, A, B, X[ 5], 11 );
-    P( B, C, D, A, X[13], 15 );
-    P( A, B, C, D, X[ 3],  3 );
-    P( D, A, B, C, X[11],  9 );
-    P( C, D, A, B, X[ 7], 11 );
-    P( B, C, D, A, X[15], 15 );
+    P( local.A, local.B, local.C, local.D, local.X[ 0],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 8],  9 );
+    P( local.C, local.D, local.A, local.B, local.X[ 4], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[12], 15 );
+    P( local.A, local.B, local.C, local.D, local.X[ 2],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[10],  9 );
+    P( local.C, local.D, local.A, local.B, local.X[ 6], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[14], 15 );
+    P( local.A, local.B, local.C, local.D, local.X[ 1],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[ 9],  9 );
+    P( local.C, local.D, local.A, local.B, local.X[ 5], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[13], 15 );
+    P( local.A, local.B, local.C, local.D, local.X[ 3],  3 );
+    P( local.D, local.A, local.B, local.C, local.X[11],  9 );
+    P( local.C, local.D, local.A, local.B, local.X[ 7], 11 );
+    P( local.B, local.C, local.D, local.A, local.X[15], 15 );
 
 #undef F
 #undef P
 
-    ctx->state[0] += A;
-    ctx->state[1] += B;
-    ctx->state[2] += C;
-    ctx->state[3] += D;
+    ctx->state[0] += local.A;
+    ctx->state[1] += local.B;
+    ctx->state[2] += local.C;
+    ctx->state[3] += local.D;
 
     /* Zeroise variables to clear sensitive data from memory. */
-    mbedtls_platform_zeroize( &X, sizeof( X ) );
-    mbedtls_platform_zeroize( &A, sizeof( A ) );
-    mbedtls_platform_zeroize( &B, sizeof( B ) );
-    mbedtls_platform_zeroize( &C, sizeof( C ) );
-    mbedtls_platform_zeroize( &D, sizeof( D ) );
+    mbedtls_platform_zeroize( &local, sizeof( local ) );
 
     return( 0 );
 }