diff --git a/include/polarssl/oid.h b/include/polarssl/oid.h
index b0e781f..6981237 100644
--- a/include/polarssl/oid.h
+++ b/include/polarssl/oid.h
@@ -370,8 +370,9 @@
  */
 int oid_get_pk_alg( const asn1_buf *oid, pk_type_t *pk_alg );
 
+#if defined(POLARSSL_ECP_C)
 /**
- * \brief          Translate ECParameters OID into an EC group identifier
+ * \brief          Translate NamedCurve OID into an EC group identifier
  *
  * \param oid      OID to use
  * \param grp_id   place to store group id
@@ -380,6 +381,19 @@
  */
 int oid_get_ec_grp( const asn1_buf *oid, ecp_group_id *grp_id );
 
+/**
+ * \brief           Translate EC group identifier into NamedCurve OID
+ *
+ * \param grp_id    EC group identifier
+ * \param oid      place to store ASN.1 OID string pointer
+ * \param olen     length of the OID
+ *
+ * \return         0 if successful, or POLARSSL_ERR_OID_NOT_FOUND
+ */
+int oid_get_oid_by_ec_grp( ecp_group_id grp_id,
+                           const char **oid, size_t *olen );
+#endif /* POLARSSL_ECP_C */
+
 #if defined(POLARSSL_MD_C)
 /**
  * \brief          Translate SignatureAlgorithm OID into md_type and pk_type