ssikit_trustchain/main.py

import asyncio
from typing import Callable, Any
import didkit
import json
from jinja2 import Environment, FileSystemLoader, select_autoescape
import idhub_ssikit
from ast import literal_eval
import copy


def deep_merge_dict_inplace(d1: dict, d2: dict):
    """
    Implements d1 |= d2, but recursively.
    Merges d1 and d2, giving preference to keys in d2.
    Keys in d1 but not in d2 are left as-is.
    """
    for key, val in d2.items():
        if isinstance(d1.get(key, None), dict) and isinstance(val, dict):
            deep_merge_dict_inplace(d1[key], val)
            continue
        d1[key] = val


def deep_merge_dict(d1: dict, d2: dict) -> dict:
    """
    Implements d1 | d2, but recursively.
    Merges d1 and d2, giving preference to keys in d2.
    Keys in d1 but not in d2 are left as-is.
    """
    d1 = copy.deepcopy(d1)
    deep_merge_dict_inplace(d1, d2)
    return d1


def deep_filter_dict(f: Callable[[Any], bool], d: dict):
    """
    Implements builtin filter(), but recursively.
    Applies f to all k,v pairs in d. If some v is a dict, recurse into v instead of applying f(v) directly.
    """
    for key, val in d.items():
        if isinstance(val, dict):
            yield key, dict(deep_filter_dict(f, val))
        elif f(val):
            yield key, val


def test_all_vcs():
    vcs = [
        'membership-card',
        'financial-vulnerability',
        'course-credential',
        'federation-membership',
    ]
    for vc in vcs:
        print(f"trying {vc}... ", end="")
        try:
            signed_cred = issue_vc_test_newstyle(vc)
            ok, err = idhub_ssikit.verify_credential(signed_cred)
            if ok:
                print("OK")
            else:
                print("FAILED!", err)
            open(f'/tmp/{vc}', mode='w').write(signed_cred)
        except Exception as e:
            print("FAILED! With exception:")
            print(e)


def issue_vc_test_newstyle(vc_name):
    jwk_issuer = didkit.generate_ed25519_key()
    jwk_subject = didkit.generate_ed25519_key()

    did_issuer = didkit.key_to_did("key", jwk_issuer)
    did_subject = didkit.key_to_did("key", jwk_subject)

    vc_template = json.load(open(f'vc_templates/{vc_name}.json'))
    data_base = json.load(open(f'vc_templates/base--data.json'))
    data_base["issuer"]["id"] = did_issuer
    data_base["credentialSubject"]["id"] = did_subject
    data_specific = json.load(open(f'vc_templates/{vc_name}--data.json'))
    data = deep_merge_dict(data_base, data_specific)
    vc_rendered_unsigned = deep_merge_dict(vc_template, data)

    signed_credential = idhub_ssikit.render_and_sign_credential(
        vc_rendered_unsigned,
        jwk_issuer,
    )
    return signed_credential


def issue_vc_test_and_fail_verification(vc_name):
    signed_credential = issue_vc_test_newstyle(vc_name)
    verification_result = idhub_ssikit.verify_credential(signed_credential)
    print(verification_result)

    def replace(s, position, character):
        return s[:position] + character + s[position+1:]
    signed_credential = replace(signed_credential, (len(signed_credential)//4)*3, ".")
    verification_result = idhub_ssikit.verify_credential(signed_credential)
    print(verification_result)


def issue_and_sign_vp_test():
    """
    In this example execution two Verifiable Credentials associated with a single Holder are issued and then
    combined into a single Verifiable Presentation.
    The Verifiable Credentials are of two different models. The use-case is meant to mimic
        - Holder being a physical person,
        - Issuer A being "Pare Manel" foundation,
        - Issuer B being "EXO" foundation,
        - Verifier (not pictured) being "Som Connexio", which wants verifiable data of the Holder from both Issuers.
    """
    jwk_issuer = didkit.generate_ed25519_key()
    jwk_issuer2 = didkit.generate_ed25519_key()
    jwk_subject = didkit.generate_ed25519_key()

    did_issuer = didkit.key_to_did("key", jwk_issuer)
    did_issuer2 = didkit.key_to_did("key", jwk_issuer2)
    did_subject = didkit.key_to_did("key", jwk_subject)
    print(did_issuer)
    print(did_issuer2)
    print(did_subject)

    env = Environment(
        loader=FileSystemLoader("vc_templates"),
        autoescape=select_autoescape()
    )
    unsigned_vc_template = env.get_template("member.json")
    data = {
        "vc_id": "http://example.org/credentials/3731",
        "issuer_did": did_issuer,
        "subject_did": did_subject,
        "issuance_date": "2020-08-19T21:41:50Z",
        "subject_is_member_of": "Pangea"
    }
    signed_credential = idhub_ssikit.render_and_sign_credential(
        unsigned_vc_template,
        jwk_issuer,
        data
    )
    data2 = data
    data2["issuer_did"] = did_issuer2
    signed_credential2 = idhub_ssikit.render_and_sign_credential(
        unsigned_vc_template,
        jwk_issuer2,
        data2
    )
    signed_presentation = idhub_ssikit.issue_verifiable_presentation([signed_credential, signed_credential2], jwk_subject, did_subject)
    print("##############--- SIGNED PRESENTATION ---##############")
    print(signed_presentation)
    print("##############--- ------------------- ---##############")

    res = idhub_ssikit.verify_presentation(signed_presentation)
    print(res)