diff --git a/benchmark/script.js b/benchmark/script.js
index 7442d1a..1ec27f3 100644
--- a/benchmark/script.js
+++ b/benchmark/script.js
@@ -32,6 +32,14 @@ async.series([
       }
     }
 
+    function isPublicKeyOut() {
+      if (c >= scripts.length) {
+        c = 0;
+      }
+      scripts[c].isPublicKeyOut();
+      c++;
+    }
+
     function isPublicKeyHashIn() {
       if (c >= scripts.length) {
         c = 0;
@@ -58,6 +66,7 @@ async.series([
 
     var suite = new benchmark.Suite();
     suite.add('isPublicKeyHashIn', isPublicKeyHashIn, {maxTime: maxTime});
+    suite.add('isPublicKeyOut', isPublicKeyOut, {maxTime: maxTime});
     suite.add('toAddress', toAddress, {maxTime: maxTime});
     suite.add('getAddressInfo', getAddressInfo, {maxTime: maxTime});
     suite
diff --git a/lib/script/script.js b/lib/script/script.js
index 5bcdce6..0fe1435 100644
--- a/lib/script/script.js
+++ b/lib/script/script.js
@@ -276,10 +276,21 @@ Script.prototype.getPublicKeyHash = function() {
  * @returns {boolean} if this is a public key output script
  */
 Script.prototype.isPublicKeyOut = function() {
-  return this.chunks.length === 2 &&
-    BufferUtil.isBuffer(this.chunks[0].buf) &&
-    PublicKey.isValid(this.chunks[0].buf) &&
-    this.chunks[1].opcodenum === Opcode.OP_CHECKSIG;
+  if (this.chunks.length === 2 &&
+      this.chunks[0].buf &&
+      this.chunks[0].buf.length &&
+      this.chunks[1].opcodenum === Opcode.OP_CHECKSIG) {
+    var pubkeyBuf = this.chunks[0].buf;
+    var version = pubkeyBuf[0];
+    if ((version === 0x04 ||
+         version === 0x06 ||
+         version === 0x07) && pubkeyBuf.length === 65) {
+      return true;
+    } else if ((version === 0x03 || version === 0x02) && pubkeyBuf.length === 33) {
+      return true;
+    }
+  }
+  return false;
 };
 
 /**