Skip to content

Latest commit

 

History

History
223 lines (137 loc) · 4.24 KB

README.md

File metadata and controls

223 lines (137 loc) · 4.24 KB

Fiat Shamir Protocol Library

What's This ?

Fiat Shamir Protocol is one of Zero Knowledge Proof Protocol that doesn't require the sender to send his credentials . Instead One can prove his / her identity by using Digital Signatures (sort of)

image

Is this Secure ?

Well Kind of but can't be used in production yet... I mean the implementation is just a Proof Of Concept and Future scope of adding more to it exists

Implementation Details

Most of the Details are in the Code itself But I am including the same for Documentation Purposes here...

  • This is intended to be on Authentication of Client -Server over TCP
  • There is a Provision of 2 Structures one for the Verifier and other for the prover. 
    • typedef struct FSP_snd{
	
	lli n,rand,x,y;
	lli secret;
	lli PUBLIC_KEY;
}fsp_snd;
    typedef struct FSP_recv{
	lli prime2, prime1;
	lli n,challenge;
	lli PUBLIC_KEY;
}fsp_recv;
  • Verifier Native Functions :

    • 1.Setup Reciever:

      Choose Arbitrary prime and send n to prover (Registration Phase )

      • lli Setup_reciever(fsp_recv*);

    • 2.Challenge Prover:

      Challenge Can be any Rand Number

      • lli challenge_phase(fsp_recv*,lli);

    • 3.Verify:

      Verify the same recieved from Response Phase(Prover) with y**2%n

      • bool verification_phase(fsp_recv*,lli,lli);
  • Prover Native Functions :

    • 1.Setup Phase: Prover Has a secret Key : s And Sends Public Key to Reciever (Verifier)

      •     lli Setup_sender(fsp_snd*,lli,lli);

    • 2.Commit Phase: Chooses a random value and bound it by common n and Send the same

      • lli  commit_phase(fsp_snd*);

    • 3.Response Phase : Respond to the challenge

      • lli response_phase(fsp_snd*,lli);

    • Build Instructions

    Clone this sub-repository and Maintain the Folder Structure as in this case .

    Portablity : This library can be ported to Python and can be used as is in Vanilla C

    For Testing Modify the test.c File and Run:

    make  test

    For Porting to python/JS : Run :

    make Clean
    make SharedLib

    to create a shared object file and use the .so file as a starter.

    Caveats

  • Do note that this was tested on a Linux System .. What may have compiled for me wouldn't for you if you would. So It is recommended to run the Make Clean && Make SharedLib commands above
  • This will not work on Windows . You need a MINGW / Equivalent compiler and compile the same to .dll file as opposed to .so file .
  • If you Have Troubles Working with generating shared library Run objdump -D lib.so

    to identify if the Function Implementation is there and the namespace isn't mangled..

    • Future Scope

    This current version is just a proof of concept version of ZKP . However there exist many complex algorithms in the wild out there The aim of the Entire Repository is to try and implement these algorithms with minimal dependencies. I mean from scratch ..

    So What's Beyond this ?

    If possible this shall be maintained regularly and I shall add a bit of complexity as such

  • Further improvements to use openssl for prime generation
  • Use longer datatypes rather than lli -> Port to gmp for arbitrary numerical precision
  • Need to add Public Key Infrastructure( PKI ) for Key Distribution Otherwise this is useless
  • Do Note that the sender public Key has to be registered.(Need to add Database Support YET!)
    • After this is done this should be a relatively well built Library which is cross-platform (partly)

    Use Case

    See Implementation for implementation in Python using this Library with the help of ctypes

    Image Credits

    Medium