diff --git a/src/util.js b/src/util.js
index 4cca968a..0b7fff83 100644
--- a/src/util.js
+++ b/src/util.js
@@ -594,13 +594,6 @@ export default {
     }
   },
 
-  isUserId: function(data) {
-    if (!util.isString(data)) {
-      return false;
-    }
-    return /</.test(data) && />$/.test(data);
-  },
-
   /**
    * Normalize line endings to \r\n
    */
diff --git a/test/general/util.js b/test/general/util.js
index bcc96f8c..cb0b4daf 100644
--- a/test/general/util.js
+++ b/test/general/util.js
@@ -116,37 +116,6 @@ describe('Util unit tests', function() {
     });
   });
 
-  describe('isUserId', function() {
-    it('should return true for valid user id', function() {
-      const data = 'Test User <test@example.com>';
-      expect(openpgp.util.isUserId(data)).to.be.true;
-    });
-    it('should return false for invalid user id', function() {
-      const data = 'Test User test@example.com>';
-      expect(openpgp.util.isUserId(data)).to.be.false;
-    });
-    it('should return false for invalid user id', function() {
-      const data = 'Test User <test@example.com';
-      expect(openpgp.util.isUserId(data)).to.be.false;
-    });
-    it('should return false for invalid user id', function() {
-      const data = 'Test User test@example.com';
-      expect(openpgp.util.isUserId(data)).to.be.false;
-    });
-    it('should return false for empty string', function() {
-      const data = '';
-      expect(openpgp.util.isUserId(data)).to.be.false;
-    });
-    it('should return false for undefined', function() {
-      let data;
-      expect(openpgp.util.isUserId(data)).to.be.false;
-    });
-    it('should return false for Object', function() {
-      const data = {};
-      expect(openpgp.util.isUserId(data)).to.be.false;
-    });
-  });
-
   describe('getTransferables', function() {
     let zero_copyVal;
     const buf1 = new Uint8Array(1);