diff --git a/src/fido/cbor_make_credential.c b/src/fido/cbor_make_credential.c
index b9de407..a0a100e 100644
--- a/src/fido/cbor_make_credential.c
+++ b/src/fido/cbor_make_credential.c
@@ -119,6 +119,7 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
                 CBOR_FIELD_KEY_TEXT_VAL_BOOL(2, "hmac-secret", extensions.hmac_secret);
                 CBOR_FIELD_KEY_TEXT_VAL_UINT(2, "credProtect", extensions.credProtect);
                 CBOR_FIELD_KEY_TEXT_VAL_BOOL(2, "minPinLength", extensions.minPinLength);
+                CBOR_FIELD_KEY_TEXT_VAL_BYTES(2, "credBlob", extensions.credBlob);
                 CBOR_ADVANCE(2);
             }
             CBOR_PARSE_MAP_END(_f1, 2);
@@ -289,7 +290,13 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
                 }
             }
         }
+        if (extensions.credBlob.present == true)
+            l++;
         CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, l));
+        if (extensions.credBlob.present == true) {
+            CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder, "credBlob"));
+            CBOR_CHECK(cbor_encode_boolean(&mapEncoder, extensions.credBlob.len < MAX_CREDBLOB_LENGTH));
+        }
         if (extensions.credProtect != 0) {
             CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder, "credProtect"));
             CBOR_CHECK(cbor_encode_uint(&mapEncoder, extensions.credProtect));