{"algorithm":"Ed25519","public_key_base64":"WC42J6G1EHFTIeG9181t9EJ5rVLHUvAhoSjwNn5Uoek=","ephemeral":true,"note":"Signature covers a canonical JSON serialisation of the response body with the 'attestation' field removed: sorted keys, separators (',',':'), UTF-8. Verify with Ed25519 over those exact bytes. WARNING: this key is derived from public data because TG_ATTEST_KEY is unset -- treat it as an integrity checksum, not as proof of origin against an adversary.","verify_example":"from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey; import base64, json; body = dict(resp); att = body.pop('attestation'); msg = json.dumps(body, sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); Ed25519PublicKey.from_public_bytes(base64.b64decode(PUB)).verify(base64.b64decode(att['signature']), msg)"}