test.py

from pbs import *
from pbs import Signer
from pbs import User
from fastecdsa.keys import gen_keypair, import_key
from fastecdsa.curve import P224
import json


if __name__ == "__main__":
    msg = "Hello"
    info = "World"
    curve = P224

    priv, _ = import_key("key.pri", P224, False)
    _ , pub = import_key("key.pub", P224, True)

    #priv, pub = gen_keypair(curve)


    s = Signer(priv)
    u = User(pub)

    #Step 1: signer generates parameters for the signature based on public info, the unencrypted metadata that goes along with this signature
    #signer_state is the returned state of the signer needed to continue this signature later one
    #If multiple signature are happening in parallel these states need to be saved and given back to the sign() function correctly later
    signer_state, params = s.generate_params(info)

    signer_state2, params2 = s.generate_params(info)
    
    #Dump params to JSON and load back again to check that they are equal
    j = json.dumps(params, cls=ECEncoder)
    paramsj= json.loads(j, object_hook=as_sig_params)

    assert params.a == paramsj.a and params.b == paramsj.b, "Error saving and loading from JSON"

    #Test encoding/decoding dictionaries of objects
    d = {}
    d["1"] = params
    d["2"] = params2
    d["4"] = "Hello"
    j = json.dumps(d, cls=ECEncoder)
    jd = json.loads(j, object_hook=as_dict)
    print(d)
    print(jd)

    # Network communication #1 from Apple to User would go here

    #Step 2: client generates signature request including the message they want signed.  The message is blinded and returned.  client_state includes random variables needed to unblind the signature later and must be passed into the unblind() function.
    client_state, req = u.generate_signature_request(params, msg, info)

    # Network communication #2 from User to Apple would go here
    
    #Step 3: signer signs the request
    blinded_sig = s.sign(signer_state, req)

    # Network communication #3 from Apple to User would go here

    #Step 4: client unblinds the signature to receive the UnblindedSignature object
    sig = u.unblind(client_state, blinded_sig, msg, info)

    #Verify that the signature is correct
    assert verify_signature(sig, pub), "Signature verification failed"

    print("Looks like it all works!")