diff --git a/library/pkparse.c b/library/pkparse.c
index 89a0c5d..6e22ce4 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -182,7 +182,8 @@
     int ret;
 
     if ( end - *p < 1 )
-        return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
+        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +
+                MBEDTLS_ERR_ASN1_OUT_OF_DATA );
 
     /* Tag may be either OID or SEQUENCE */
     params->tag = **p;