This paper proposes a method to prevent parameter tampering on web services. Time based hash encryption is able to give unpredictable output which changes periodically ac-cording to input. The proposed method uses different parts of function output as authenti-cation key and parameter order. The presented method has several characteristics. Each encryption and decryption needs to be able to generate the same VST. Vst used must have a periodic record so that it is pos-sible to get Vs (t-1).Each used Vst works without trouble on both time variants (tests 1-3) and invariant (tests 3-5). From the Decrypt column, we can see that, as a side effect, each pass parameter is decrypted and cut off. To evaluate proposed work, we make software to encrypt and decrypt a request. We limit the test to having no delay.

Keywords : Securing Client, Server Connections, Tampering, Encryption.