diff --git a/library/rsa.c b/library/rsa.c
index 637c23a..5d7129a 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -440,7 +440,6 @@
                 return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
 
             memset( output, 0, olen );
-            memset( &md_ctx, 0, sizeof( md_context_t ) );
 
             md_init_ctx( &md_ctx, md_info );
 
@@ -470,6 +469,8 @@
             //
             mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,  
                        &md_ctx );
+
+            md_free_ctx( &md_ctx );
             break;
 #endif
 
@@ -566,7 +567,6 @@
                 return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
                 
             hlen = md_get_size( md_info );
-            memset( &md_ctx, 0, sizeof( md_context_t ) );
 
             md_init_ctx( &md_ctx, md_info );
             
@@ -585,6 +585,7 @@
                        &md_ctx );
 
             p += hlen;
+            md_free_ctx( &md_ctx );
 
             // Check validity
             //
@@ -798,7 +799,6 @@
                 return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
 
             memset( sig, 0, olen );
-            memset( &md_ctx, 0, sizeof( md_context_t ) );
 
             md_init_ctx( &md_ctx, md_info );
 
@@ -834,6 +834,8 @@
             //
             mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen, &md_ctx );
 
+            md_free_ctx( &md_ctx );
+
             msb = mpi_msb( &ctx->N ) - 1;
             sig[0] &= 0xFF >> ( olen * 8 - msb );
 
@@ -1012,7 +1014,6 @@
             hlen = md_get_size( md_info );
             slen = siglen - hlen - 1;
 
-            memset( &md_ctx, 0, sizeof( md_context_t ) );
             memset( zeros, 0, 8 );
 
             md_init_ctx( &md_ctx, md_info );
@@ -1054,6 +1055,8 @@
             md_update( &md_ctx, p, slen );
             md_finish( &md_ctx, result );
 
+            md_free_ctx( &md_ctx );
+
             if( memcmp( p + slen, result, hlen ) == 0 )
                 return( 0 );
             else