Delphi JOSE and JWT Library

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Delphi implementation of JWT (JSON Web Token) and the JOSE (JSON Object Signing and Encryption) specification suite. This library supports the JWS (JWE is support planned) compact serializations with several JOSE algorithms.

Important!

The HMAC algorithm uses OpenSSL through the Indy library, so in order to generate the token you should have the OpenSSL DLLs in your server system. The client doesn't have to generate or verify the token (using HMAC) so on the client-side there's no need for the OpenSSL DLLs. You can download the OpenSSL package at the fulgan website (keep in mind to always update to the latest version)

What is JOSE

JOSE is a standard that provides a general approach to signing and encryption of any content. JOSE consists of several RFC:

• JWT (JSON Web Token) - describes representation of claims encoded in JSON
• JWS (JSON Web Signature) - describes producing and handling signed messages
• JWE (JSON Web Encryption) - describes producing and handling encrypted messages
• JWA (JSON Web Algorithms) - describes cryptographic algorithms used in JOSE
• JWK (JSON Web Key) - describes format and handling of cryptographic keys in JOSE

General Features

• Token serialization
• Token deserialization
• Claims validation
  • exp, iat, nbf claims validatation - supported
  • aud, iss, sub claims validatation - planned
• Sign algorithms
  • NONE, HS256, HS384, HS512 algorithms - supported
• Encryption algorithms
  • RS256, RS384, RS512 algorithms - planned
  • ES256, ES384, ES512, PS256, PS384, PS512 algorithms - not (yet) planned
  • Not affected by theNonealgorithm vulnerability

This library is not susceptible to the recently discussed encryption vulnerability.

Projects using Delphi JOSE and JWT

• TMS XData and TMS Sparkle. Read the blog post by Wagner R. Landgraf (he is also a contributor of this project)
• The WiRL RESTful Library for Delphi

Todo

Features

• Token validation: aud, iss, sub
• RSA algorithms implementation
• Easy creation of TJWTClaims derived classes

Code

• D2010+ porting
• Unit Tests
• More examples

Prerequisite

This library has been tested with Delphi 10.1 Berlin, Delphi 10 Seattle and Delphi XE8 but with a minimum amount of work it should compile with D2010 and higher

Libraries/Units dependencies

This library has no dependencies on external libraries/units.

Delphi units used:

• System.JSON (DXE6+) (available on earlier Delphi versions as Data.DBXJSON)
• System.Rtti (D2010+)
• System.Generics.Collections (D2009+)
• System.NetEncoding (DXE7+)
• Indy units: IdHMAC, IdHMACSHA1, IdSSLOpenSSL, IdHash (please use latest version from svn)

Installation

Simply add the source path "Source/Common" and Source/JOSE" to your Delphi project path and.. you are good to go!

Code Examples

Creating a token

To create a token simple create an instance of the TJWT class and set the properties (claims). The easiest way to serialize, deserialize, verify a token is to use the TJOSEutility class.

var
  LToken: TJWT;
begin
  LToken := TJWT.Create;
  try
    // Token claims
    LToken.Claims.IssuedAt := Now;
    LToken.Claims.Expiration := Now + 1;
    LToken.Claims.Issuer := 'WiRL REST Library';

    // Signing and Compact format creation
    mmoCompact.Lines.Add(TJOSE.SHA256CompactToken('secret', LToken));

    // Header and Claims JSON representation
    mmoJSON.Lines.Add(LToken.Header.JSON.ToJSON);
    mmoJSON.Lines.Add(LToken.Claims.JSON.ToJSON);
  finally
    LToken.Free;
  end;

Unpack and Verify a token

Unpacking and verifying tokens is simple. You have to pass the key (secret) and the token compact format to the TJOSE.Verify class function

var
  LKey: TJWK;
  LToken: TJWT;
begin
  LKey := TJWK.Create('secret');
  // Unpack and verify the token
  LToken := TJOSE.Verify(LKey, 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJXaVJMIn0.w3BAZ_GwfQYY6dkS8xKUNZ_sOnkDUMELxBN0mKKNhJ4');

  if Assigned(LToken) then
  begin
    try
      if LToken.Verified then
        mmoJSON.Lines.Add('Token signature is verified')
      else
        mmoJSON.Lines.Add('Token signature is not verified')
    finally
      LToken.Free;
    end;
  end;

end;

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Paolo Rossi