heyitsmass / hmac

A simple HMAC wrapper to send and receive validated messages between server and client.

Tamper Proof Data

SecureConnection: A simple, zero dependency HMAC wrapper for the native browser crypto module to send and receive validated messages between server and client.

• establish():Promise<SecureConnection>

  • Establishes a secure 'connection' between the client and server.
  • For a connection to be secure the client must have
    • An HMAC key present in localStorage (auto-generated).
    • Initial data.
    • Signature to reference data against.

• get<T,>() => Promise<T>

  • Provides GET functionality from the server.
  • Messages are signed by the client and transmitted to the server.
  • The response must contain the signature sent by the client, re-validated on return.

• send<T,>(data:T) => Promise<T>

  • Provides POST functionality to the server from the client.
  • Messages are signed by the client, data is saved into the localStorage.
  • Upon saving the data, the get process is repeated to validate and update the data.

• verify() => Promise<boolean>

  • Provides verification functionality of the client data.
  • Known data and signature is collected from the client.
  • Data is requested from the server and validated against the client's known data.
  • If the data is invalid, the user is prompted to restore the data from the preexisting client data.