diff --git a/phpseclib/Crypt/RSA.php b/phpseclib/Crypt/RSA.php
index 5e55917f..ba2a8d83 100644
--- a/phpseclib/Crypt/RSA.php
+++ b/phpseclib/Crypt/RSA.php
@@ -188,7 +188,7 @@ class RSA
     /**
      * PKCS#8 formatted private key
      */
-    const PRIVATE_FORMAT_PKCS8 = 3;
+    const PRIVATE_FORMAT_PKCS8 = 8;
     /**#@-*/
 
     /**#@+
diff --git a/tests/Unit/Crypt/RSA/LoadKeyTest.php b/tests/Unit/Crypt/RSA/LoadKeyTest.php
index a80b8d2f..6a11db60 100644
--- a/tests/Unit/Crypt/RSA/LoadKeyTest.php
+++ b/tests/Unit/Crypt/RSA/LoadKeyTest.php
@@ -317,4 +317,33 @@ JWrQdxx/WNN+ABG426rgYYbeGcIlWLZCw6Bx/1HtN5ef6nVEoiGNChYKIRB4QFOi
 
         $this->assertSame(preg_replace('#\s#', '', $key), preg_replace('#\s#', '', $newkey));
     }
+
+    /**
+     * @group github861
+     */
+    public function testPKCS8Only()
+    {
+        $rsa = new RSA();
+
+        $key = '-----BEGIN PRIVATE KEY-----
+MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAKB0yPMAbUHKqJxP
+5sjG9AOrQSAYNDc34NsnZ1tsi7fZ9lHlBaKZ6gjm2U9q+/qCKv2BuGINxWo2CMJp
+DHNY0QTt7hThr3B4U62z1CWWGnfLhFtHKH6jNYYOGc4x0jgT88uSrKFvUOLhjkjW
+bURmJMpN+OjLJuZQZ7uwoqtT3IEDAgMBAAECgYBaElS/fEzYst/Fp2DA8lYGPTs4
+vf2JxbdWrp7phlxEH3mTbUGljkr/Jj90wnSiojFpz0jm2h4oyh5Oq9OOaJwkCYcu
+2lcHJvFlhR2XEJpd1bHHcvDwZHdUjSpnO8kvwQtjuTnho2ntRzAA4wIJVSd7Tynj
+0IFEKmzhSKIvIIeN8QJBANLa10R1vs+YqpLdpAuc6Z9GYhHuh1TysBPw2xNtw3Xf
+tGPx4/53eQ0RwiHdw9Opgt8CBHErD6KzziflfxUrIXkCQQDCz4t01qYWT43kxS6k
+TcnZb/obho6akGc8C1hSxFIIGUa9hAhMpY2W6GXeGpv5TZtEJZIJE1VHTLvcLSGm
+ILNbAkEAgq9mWqULxYket3Yt1ZDEb5Zk9C49rJXaMhHHBoyyZ51mJcfngnE0Erid
+9PWJCOf4GBYdALMqtrHwpWOlV05rKQJAd6Tz50w1MRqm8MvRe4Ny5qIJH4Kibncl
+kBD/q8V7BBJSCe7fEgPTU81jUudQx+pL46yXZg+DnoiYD/9/3QHUZQJBAMBiKiZ7
+qMnD/pkHR/NFcYSYShUJS0cHyryVl7/eCclsQlZTRdnVTtKF9xPGTQC8fK0G7BDN
+Z2sKniRCcDT1ZP4=
+-----END PRIVATE KEY-----';
+
+        $result = $rsa->loadKey($key, RSA::PRIVATE_FORMAT_PKCS8);
+
+        $this->assertTrue($result);
+    }
 }