dspip 1.0.1

Digital Signing of Physical Items Protocol SDK - Official Python implementation

DSPIP Python SDK

Official Python implementation of the Digital Signing of Physical Items Protocol (DSPIP) per Internet-Draft draft-midwestcyber-dspip-02.

⚠️ BETA VERSION: This is a pre-release implementation of the DSPIP protocol, currently under review by the IETF. The API may change based on feedback.

Overview

DSPIP provides cryptographic authentication for physical items using digitally signed QR codes, with a focus on shipping and logistics applications.

Installation

pip install dspip

Or install from source:

git clone https://github.com/MidwestCyberLLC/dspip-python.git
cd dspip-python
pip install -e .

Quick Start

from dspip import (
    generate_key_pair,
    create_standard_payload,
    verify_offline,
    generate_qr_code_data_url,
)

# Generate a key pair
keys = generate_key_pair()
print(f"Public Key: {keys.public_key_base64}")

# Create a shipping label
qr_data = create_standard_payload(
    issuer={"name": "Acme Corp", "address": {"country": "US"}},
    recipient={"name": "John Doe", "address": {"country": "US", "city": "New York"}},
    item_id="PKG-001",
    key_locator="warehouse._dspip.example.com",
    sender_private_key_hex=keys.private_key_hex,
)

# Generate QR code
qr_image = generate_qr_code_data_url(qr_data)

# Verify offline
result = verify_offline(qr_data, keys.public_key_base64)
print(f"Valid: {result.valid}")

Features

Key Generation

from dspip import (
    generate_key_pair,
    generate_secp256k1_key_pair,
    generate_ed25519_key_pair,
)

# Generate secp256k1 key pair (default for standard/encrypted mode)
secp_keys = generate_secp256k1_key_pair()

# Generate Ed25519 key pair (for split-key mode)
ed_keys = generate_ed25519_key_pair()

# Auto-detect based on curve parameter
keys = generate_key_pair("ed25519")

Privacy Modes

DSPIP supports three privacy modes:

Standard Mode

Recipient information is visible to all parties.

from dspip import create_standard_payload

qr_data = create_standard_payload(
    issuer={"name": "Sender", "address": {"country": "US"}},
    recipient={"name": "Recipient", "address": {"country": "US"}},
    item_id="PKG-001",
    key_locator="warehouse._dspip.example.com",
    sender_private_key_hex=keys.private_key_hex,
)

Encrypted Mode

Recipient information is encrypted for the carrier.

from dspip import create_encrypted_payload

qr_data = create_encrypted_payload(
    issuer={"name": "Sender", "address": {"country": "US"}},
    recipient={"name": "Recipient", "address": {"country": "US"}},
    item_id="PKG-001",
    key_locator="warehouse._dspip.example.com",
    sender_private_key_hex=sender_keys.private_key_hex,
    carrier_public_key_hex=carrier_keys.public_key_hex,
    lmp_address="plus:87G8Q2JM+HV",
)

Split-Key Mode

Recipient information is encrypted for the last-mile provider using Ed25519/X25519.

from dspip import create_split_key_payload, generate_ed25519_key_pair

sender_keys = generate_ed25519_key_pair()
lmp_keys = generate_ed25519_key_pair()

qr_data = create_split_key_payload(
    issuer={"name": "Sender", "address": {"country": "US"}},
    recipient={"name": "Recipient", "address": {"country": "US"}},
    item_id="PKG-001",
    key_locator="warehouse._dspip.example.com",
    sender_private_key_hex=sender_keys.private_key_hex,
    lmp_public_key_hex=lmp_keys.public_key_hex,
    lmp_address="plus:87G8Q2JM+HV",
)

DNS Records

from dspip import (
    create_dns_record,
    format_dns_record,
    parse_dns_record,
    create_key_lifecycle,
)

# Create a DNS record
record = create_dns_record(
    public_key_base64=keys.public_key_base64,
    curve="secp256k1",
)

# Format for DNS TXT record
txt_record = format_dns_record(record)
# v=DSPIP1; k=ec; c=secp256k1; p=...

# Create with lifecycle management
record = create_key_lifecycle(
    public_key_base64=keys.public_key_base64,
    private_key_hex=keys.private_key_hex,
    signing_days=365,
    verification_grace_days=90,
)

Address Schemes

from dspip import (
    create_plus_code_address,
    create_street_address,
    create_geo_address,
    create_facility_address,
    parse_address_field,
)

# Plus Code (Google Open Location Code)
addr = create_plus_code_address("87G8Q2JM+HV")

# Street address (percent-encoded)
addr = create_street_address("123 Main St, New York, NY 10001")

# Geo coordinates (RFC 5870)
addr = create_geo_address(40.7128, -74.0060, uncertainty=10)

# Facility identifier
addr = create_facility_address("NYC-SORT-01")

# Parse any address format
parsed = parse_address_field("plus:87G8Q2JM+HV")
print(f"Scheme: {parsed.scheme}, Value: {parsed.value}")

Verification

import asyncio
from dspip import verify, verify_offline, verify_and_decrypt

# Offline verification with known public key
result = verify_offline(qr_data, public_key_base64)

# Online verification with DNS lookup
async def verify_label():
    result = await verify(qr_data)
    if result.valid:
        print(f"Verified! Signed by: {result.signed_by}")
    else:
        for error in result.errors:
            print(f"Error: {error.message}")

asyncio.run(verify_label())

# Verify and decrypt (for encrypted mode)
async def verify_and_decrypt_label():
    result = await verify_and_decrypt(qr_data, carrier_private_key_hex)
    if result.valid and result.decrypted_recipient:
        print(f"Recipient: {result.decrypted_recipient['recipientName']}")

asyncio.run(verify_and_decrypt_label())

QR Code Generation

from dspip import (
    generate_qr_code_data_url,
    generate_qr_code_svg,
    generate_qr_code_terminal,
    save_qr_code_to_file,
    will_fit_in_qr_code,
)

# Generate as data URL (for HTML img src)
data_url = generate_qr_code_data_url(qr_data)

# Generate as SVG
svg = generate_qr_code_svg(qr_data)

# Generate for terminal display
terminal = generate_qr_code_terminal(qr_data)
print(terminal)

# Save to file
save_qr_code_to_file(qr_data, "label.png")

# Check if data fits in QR code
if will_fit_in_qr_code(qr_data):
    print("Data fits in QR code")

API Reference

Types

• KeyPair - Key pair with hex and base64 formats
• DSPIPPayload - Main payload structure
• DSPIPQRData - QR code data structure
• DSPIPDNSRecord - DNS TXT record structure
• VerificationResult - Verification result with errors/warnings
• PrivacyMode - Enum: STANDARD, ENCRYPTED, SPLIT_KEY
• KeyStatus - Enum: ACTIVE, VERIFY_ONLY, REVOKED
• AddressScheme - Enum: PLUS, STREET, GEO, FACILITY

Crypto Functions

• generate_key_pair(curve) - Generate key pair
• sign(message_hash, private_key_hex, curve) - Sign message
• verify_signature(message_hash, signature, public_key, curve) - Verify signature
• ecies_encrypt(plaintext, public_key_hex) - ECIES encryption
• ecies_decrypt(ciphertext, private_key_hex) - ECIES decryption
• encrypt_for_lmp(data, sender_private_key, lmp_public_key) - Split-key encryption
• decrypt_as_lmp(encrypted, sender_public_key, lmp_private_key) - Split-key decryption

Payload Functions

• create_standard_payload(...) - Create standard mode payload
• create_encrypted_payload(...) - Create encrypted mode payload
• create_split_key_payload(...) - Create split-key mode payload
• encode_payload(payload) - Encode payload to Base64
• decode_payload(encoded) - Decode payload from Base64
• serialize_qr_data(qr_data) - Serialize to QR string
• parse_qr_data(data) - Parse QR string

DNS Functions

• create_dns_record(...) - Create DNS record structure
• format_dns_record(record) - Format as TXT record string
• parse_dns_record(txt) - Parse TXT record string
• resolve_dns_record(key_locator) - Resolve via DNS-over-HTTPS
• check_key_status(record) - Check if key can sign/verify

Verification Functions

• verify(qr_data) - Verify with DNS lookup
• verify_offline(qr_data, public_key) - Verify with known key
• verify_and_decrypt(qr_data, private_key) - Verify and decrypt

QR Functions

• generate_qr_code_data_url(data) - Generate as data URL
• generate_qr_code_svg(data) - Generate as SVG
• generate_qr_code_terminal(data) - Generate for terminal
• save_qr_code_to_file(data, path) - Save to file
• will_fit_in_qr_code(data) - Check if data fits

Revocation Lists

Revocation lists allow revoking item IDs (e.g., for lost, stolen, or damaged packages):

import asyncio
from dspip import (
    create_revocation_list,
    check_revocation,
    verify_revocation_list,
    calculate_bloom_filter_size,
)

# Create a signed revocation list with Bloom filter
revocation_list = create_revocation_list(
    issuer="warehouse._dspip.acme.com",
    entries=[
        {"item_id": "TRACK-001", "revoked": int(time.time()), "reason": "lost"},
        {"item_id": "TRACK-002", "revoked": int(time.time()), "reason": "stolen"},
    ],
    private_key_hex=sender_keys.private_key_hex,
    include_bloom_filter=True,
)

# Verify the list signature
is_valid = verify_revocation_list(revocation_list, sender_keys.public_key_hex)

# Check if an item is revoked
async def check():
    result = await check_revocation(
        "TRACK-001",
        cached_list=revocation_list,
        issuer_public_key_hex=sender_keys.public_key_hex,
    )
    print(f"Revoked: {result.revoked}")  # True
    print(f"Reason: {result.entry.reason}")  # 'lost'

asyncio.run(check())

# Calculate optimal Bloom filter size
params = calculate_bloom_filter_size(10000, 0.01)  # 10k items, 1% false positive
print(f"Size: {params['size']} bits, Hash count: {params['hash_count']}")

Delivery Confirmation

Cryptographic proof of delivery using challenge-response protocol:

from dspip import (
    create_delivery_challenge,
    respond_to_challenge,
    verify_delivery_response,
    create_multi_party_attestation,
    add_attestation,
)

# Step 1: Carrier creates challenge
challenge = create_delivery_challenge(
    item_id="TRACK-2025-001",
    carrier_key_locator="driver._dspip.usps.gov",
    carrier_private_key_hex=carrier_keys.private_key_hex,
)

# Step 2: Recipient signs the challenge
response = respond_to_challenge(
    challenge=challenge,
    recipient_private_key_hex=recipient_keys.private_key_hex,
    recipient_public_key_hex=recipient_keys.public_key_hex,
    metadata={
        "recipient_name": "Bob Jones",
        "location": "41.2565,-95.9345",
    },
)

# Step 3: Carrier verifies and creates proof
proof = verify_delivery_response(
    challenge=challenge,
    response=response,
    carrier_private_key_hex=carrier_keys.private_key_hex,
)

print(f"Delivery verified: {proof.valid}")
print(f"Proof hash: {proof.proof_hash}")  # For blockchain recording

# Multi-party attestation for high-value deliveries
attestation = create_multi_party_attestation(proof, required_attestations=3)
attestation = add_attestation(attestation, "carrier", "carrier", carrier_keys.private_key_hex)
attestation = add_attestation(attestation, "recipient", "recipient", recipient_keys.private_key_hex)
attestation = add_attestation(attestation, "witness", "witness", witness_keys.private_key_hex)

print(f"Complete: {attestation.complete}")  # True (3/3 attestations)

DNSSEC Validation

Validate the chain of trust from DNS root to key locator:

import asyncio
from dspip import (
    validate_dnssec,
    validate_key_locator_dnssec,
    has_dnssec,
)

async def check_dnssec():
    # Quick check: does domain have DNSSEC?
    dnssec_enabled = await has_dnssec("example.com")
    print(f"DNSSEC enabled: {dnssec_enabled}")

    # Full validation for a key locator
    result = await validate_key_locator_dnssec(
        "warehouse._dspip.example.com",
        full_chain_validation=True,
    )
    print(f"Trusted: {result['trusted']}")
    print(f"Recommendation: {result['recommendation']}")
    # "DNSSEC validated - key lookup is cryptographically authenticated"
    # OR "DNSSEC not enabled - key lookup relies on network security only"

    # Detailed validation result
    dnssec_result = await validate_dnssec("cloudflare.com")
    print(f"Chain of trust: {dnssec_result.chain_of_trust.to_dict()}")
    # {'root': True, 'tld': True, 'domain': True, 'subdomain': True}

asyncio.run(check_dnssec())

Dependencies

• coincurve - secp256k1 operations
• pynacl - Ed25519/X25519 operations
• cryptography - AES-GCM encryption
• qrcode[pil] - QR code generation
• httpx - Async HTTP for DNS resolution

License

MIT License - see LICENSE file for details.