Python SDK Guide

The Python SDK provides the same capabilities as the TypeScript SDK for validating, signing, and verifying FACT credentials. It includes full support for HTTP Message Signatures (Web Bot Auth), trust chain verification, and advanced features like selective disclosure (SD-JWT).

Features

• Validate DeveloperCredential and AgentCredential against v1 schemas
• Sign credentials as JWS/JWT with ES256 or EdDSA
• Verify signed credentials with the 7-step verification process
• Trust Chain verification with policy enforcement
• Status List 2021 revocation checking
• HTTP Message Signatures (RFC 9421) for Web Bot Auth
• Selective Disclosure (SD-JWT) for privacy-preserving credentials
• Multi-Signature support for credentials requiring multiple signers
• Audit Logging with pluggable handlers
• Rich errors with paths, rule IDs, and suggestions

Installation

pip install beltic-sdk

Requirements

• Python >= 3.10
• cryptography >= 41.0
• pyjwt[crypto] >= 2.8
• jsonschema >= 4.20
• pydantic >= 2.5
• httpx >= 0.25

Quick Start

from beltic import (
    validate_developer_credential,
    sign_credential,
    verify_credential,
    generate_key_pair,
    ValidationError,
    SignOptions,
    VerifyOptions,
)

# Generate keys
private_key, public_key = generate_key_pair("EdDSA")

# Validate a credential
result = validate_developer_credential(credential_data)
if not result.ok:
    raise ValidationError(result.errors)

# Sign a credential
token = sign_credential(
    result.value,
    private_key,
    SignOptions(
        alg="EdDSA",
        issuer_did="did:web:beltic.com",
        subject_did="did:web:developer.example.com",
        key_id="did:web:beltic.com#key-1",
    ),
)

# Verify a credential
async def key_resolver(input):
    return public_key

verified = await verify_credential(
    token,
    VerifyOptions(key_resolver=key_resolver),
)

print("Verified:", verified.credential["legalName"])

Guides

Comparison with TypeScript SDK

The Python SDK maintains feature parity with the TypeScript SDK:

See Also

• TypeScript SDK Guide
• CLI Guide
• Web Bot Auth