Message Authentication Codes or MACs are used by two parties to validate that a message hadn't been altered in transit. Only the nodes which posses the keys/Secrets may compute the MAC and validate the MAC against an input text. This page demonstrates the use of an HMAC.

Step 1(Optional): The sender enters the Secret and The Text in the Text Boxes.

Shared Key/Secret:

Message Text:

Step 2: The sender clicks the button below to generate 20-byte HMAC (since we are using HMACSHA1. It is recommedned to use HMACSHA256 if .NET 2.0).



HMAC Generated: (Base 64 encoded).

(The sender will send Text + HMAC to the receiver who has the shared secret/key.)

Step 3: (The receiver) validate the Text + HMAC received based on the Secret you share with the sender by clicking the button below. (You can change the Validation result by modifying the Message Text before hitting the Validate button.)

   (Validation Result will be Here)