diff --git a/doc/tools/pkcs11-tool.1.xml b/doc/tools/pkcs11-tool.1.xml
index f92cf5edfd8..576999daaca 100644
--- a/doc/tools/pkcs11-tool.1.xml
+++ b/doc/tools/pkcs11-tool.1.xml
@@ -148,7 +148,7 @@
 					</term>
 					<listitem><para>Specify the type and length (bytes if symmetric) of the key to create,
 					for example RSA:1024, EC:prime256v1, GOSTR3410-2012-256:B,
-					DES:8, DES3:24, AES:16 or GENERIC:64.</para></listitem>
+					DES:8, DES3:24, AES:16 or GENERIC:64. If the key type was incompletely specified, possible values are listed.</para></listitem>
 				</varlistentry>
 
 				<varlistentry>
diff --git a/src/tools/pkcs11-tool.c b/src/tools/pkcs11-tool.c
index bf7963f0285..8478f415aaf 100644
--- a/src/tools/pkcs11-tool.c
+++ b/src/tools/pkcs11-tool.c
@@ -2918,8 +2918,13 @@ static int gen_keypair(CK_SLOT_ID slot, CK_SESSION_HANDLE session,
 				if (!strcmp(ec_curve_infos[ii].oid, type + 3))
 					break;
 			}
-			if (!ec_curve_infos[ii].name)
-				util_fatal("Unknown EC key params '%s'", type + 3);
+			if (!ec_curve_infos[ii].name) {
+				fprintf(stderr, "EC key parameters may be specified by their canonic name or object identifier. Possible values are:\n");
+				for (ii=0; ec_curve_infos[ii].name; ii++)   {
+					fprintf(stderr, "%s (%s)\n", ec_curve_infos[ii].name, ec_curve_infos[ii].oid);
+				}
+				util_fatal("Unknown EC key parameter '%s'", type + 3);
+			}
 
 			switch (ec_curve_infos[ii].mechanism) {
 			case CKM_EC_EDWARDS_KEY_PAIR_GEN: