diff --git a/src/route/hkp.js b/src/route/hkp.js
index 9c74286..a1ea661 100644
--- a/src/route/hkp.js
+++ b/src/route/hkp.js
@@ -77,7 +77,7 @@ class HKP {
       params.email = ctx.query.search;
     }
 
-    if ((params.op !== 'get' && params.op !== 'index') || (params.op === 'index' && !params.mr)) {
+    if (['get','index','vindex'].indexOf(params.op) === -1) {
       ctx.throw(501, 'Not implemented!');
     } else if (!params.keyid && !params.email) {
       ctx.throw(400, 'Invalid request!');
@@ -121,7 +121,7 @@ class HKP {
   setGetBody(ctx, params, key) {
     if (params.op === 'get') {
       ctx.body = key.publicKeyArmored;
-    } else if (params.op === 'index' && params.mr) {
+    } else if (['index','vindex'].indexOf(params.op) !== -1) {
       const VERSION = 1, COUNT = 1; // number of keys
       let algo = (key.algorithm.indexOf('rsa') !== -1) ? 1 : '';
       let created = key.created ? (key.created.getTime() / 1000) : '';
diff --git a/test/integration/app-test.js b/test/integration/app-test.js
index e6d8ce9..cf90495 100644
--- a/test/integration/app-test.js
+++ b/test/integration/app-test.js
@@ -405,6 +405,14 @@ describe('Koa App (HTTP Server) Integration Tests', function() {
           .end(done);
         });
 
+        it('should return 200 for "vindex" op', done => {
+          request(app.listen())
+          .get('/pks/lookup?op=vindex&search=0x' + emailParams.keyid)
+          .expect('Content-Type', 'text/plain; charset=utf-8')
+          .expect(200)
+          .end(done);
+        });
+
         it('should return 200 for "index" with "mr" option', done => {
           request(app.listen())
           .get('/pks/lookup?op=index&options=mr&search=0x' + emailParams.keyid)
@@ -448,9 +456,9 @@ describe('Koa App (HTTP Server) Integration Tests', function() {
           .end(done);
         });
 
-        it('should return 501 (Not implemented) for "index" op', done => {
+        it('should return 501 (Not implemented) for "x-email" op', done => {
           request(app.listen())
-          .get('/pks/lookup?op=index&search=0x' + emailParams.keyid)
+          .get('/pks/lookup?op=x-email&search=0x' + emailParams.keyid)
           .expect(501)
           .end(done);
         });