diff --git a/src/netif/ppp/polarssl/md4.c b/src/netif/ppp/polarssl/md4.c
index 0572acee..3d8a8fda 100644
--- a/src/netif/ppp/polarssl/md4.c
+++ b/src/netif/ppp/polarssl/md4.c
@@ -206,7 +206,7 @@ void md4_update( md4_context *ctx, unsigned char *input, int ilen )
 
     if( left && ilen >= fill )
     {
-        memcpy( (void *) (ctx->buffer + left),
+        MEMCPY( (void *) (ctx->buffer + left),
                 (void *) input, fill );
         md4_process( ctx, ctx->buffer );
         input += fill;
@@ -223,7 +223,7 @@ void md4_update( md4_context *ctx, unsigned char *input, int ilen )
 
     if( ilen > 0 )
     {
-        memcpy( (void *) (ctx->buffer + left),
+        MEMCPY( (void *) (ctx->buffer + left),
                 (void *) input, ilen );
     }
 }
@@ -274,8 +274,6 @@ void md4( unsigned char *input, int ilen, unsigned char output[16] )
     md4_starts( &ctx );
     md4_update( &ctx, input, ilen );
     md4_finish( &ctx, output );
-
-    memset( &ctx, 0, sizeof( md4_context ) );
 }
 
 #endif /* LWIP_INCLUDED_POLARSSL_MD4_C */
diff --git a/src/netif/ppp/polarssl/md5.c b/src/netif/ppp/polarssl/md5.c
index cd800a92..a98e8289 100644
--- a/src/netif/ppp/polarssl/md5.c
+++ b/src/netif/ppp/polarssl/md5.c
@@ -225,7 +225,7 @@ void md5_update( md5_context *ctx, unsigned char *input, int ilen )
 
     if( left && ilen >= fill )
     {
-        memcpy( (void *) (ctx->buffer + left),
+        MEMCPY( (void *) (ctx->buffer + left),
                 (void *) input, fill );
         md5_process( ctx, ctx->buffer );
         input += fill;
@@ -242,7 +242,7 @@ void md5_update( md5_context *ctx, unsigned char *input, int ilen )
 
     if( ilen > 0 )
     {
-        memcpy( (void *) (ctx->buffer + left),
+        MEMCPY( (void *) (ctx->buffer + left),
                 (void *) input, ilen );
     }
 }
@@ -293,8 +293,6 @@ void md5( unsigned char *input, int ilen, unsigned char output[16] )
     md5_starts( &ctx );
     md5_update( &ctx, input, ilen );
     md5_finish( &ctx, output );
-
-    memset( &ctx, 0, sizeof( md5_context ) );
 }
 
 #endif /* LWIP_INCLUDED_POLARSSL_MD5_C */
diff --git a/src/netif/ppp/polarssl/sha1.c b/src/netif/ppp/polarssl/sha1.c
index 9649ddf4..6d6e682a 100644
--- a/src/netif/ppp/polarssl/sha1.c
+++ b/src/netif/ppp/polarssl/sha1.c
@@ -259,7 +259,7 @@ void sha1_update( sha1_context *ctx, unsigned char *input, int ilen )
 
     if( left && ilen >= fill )
     {
-        memcpy( (void *) (ctx->buffer + left),
+        MEMCPY( (void *) (ctx->buffer + left),
                 (void *) input, fill );
         sha1_process( ctx, ctx->buffer );
         input += fill;
@@ -276,7 +276,7 @@ void sha1_update( sha1_context *ctx, unsigned char *input, int ilen )
 
     if( ilen > 0 )
     {
-        memcpy( (void *) (ctx->buffer + left),
+        MEMCPY( (void *) (ctx->buffer + left),
                 (void *) input, ilen );
     }
 }
@@ -328,8 +328,6 @@ void sha1( unsigned char *input, int ilen, unsigned char output[20] )
     sha1_starts( &ctx );
     sha1_update( &ctx, input, ilen );
     sha1_finish( &ctx, output );
-
-    memset( &ctx, 0, sizeof( sha1_context ) );
 }
 
 #endif /* LWIP_INCLUDED_POLARSSL_SHA1_C */