int EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
	{
	/* Don't assume ctx->md_data was cleaned in EVP_Digest_Final,
	 * because sometimes only copies of the context are ever finalised.
	 */
	if (ctx->digest && ctx->digest->cleanup
	    && !EVP_MD_CTX_test_flags(ctx,EVP_MD_CTX_FLAG_CLEANED))
		ctx->digest->cleanup(ctx);
	if (ctx->digest && ctx->digest->ctx_size && ctx->md_data
	    && !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE))
		{
		OPENSSL_cleanse(ctx->md_data,ctx->digest->ctx_size);
		OPENSSL_free(ctx->md_data);
		}
	if (ctx->pctx)
		EVP_PKEY_CTX_free(ctx->pctx);
#ifndef OPENSSL_NO_ENGINE
	if(ctx->engine)
		/* The EVP_MD we used belongs to an ENGINE, release the
		 * functional reference we held for this reason. */
		ENGINE_finish(ctx->engine);
#endif
	memset(ctx,'\0',sizeof *ctx);

	return 1;
	}