]> Midwest Cyber LLC

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Security Internet Engineering Task Force digital-signature shipping qr-code cryptography dns pki This document specifies the Digital Signing of Physical Items Protocol (DSPIP), a cryptographic protocol for authenticating physical items using digitally signed QR codes. This specification focuses on the SHIP type for shipping and logistics applications, providing cryptographic authentication of packages with chain of custody tracking. The protocol introduces privacy-preserving delivery mechanisms including encrypted recipient information, last mile provider selection, physical anti-cloning protections through split-key labels, and scalable revocation and delivery confirmation systems. DSPIP uses DNS-based public key distribution similar to DKIM and supports optional blockchain integration for immutable record keeping. While this specification focuses on shipping applications, the protocol includes a type field to enable future expansion to other use cases.

Introduction Supply chain logistics require verifiable proof of package authenticity, chain of custody, and delivery confirmation. Current shipping systems rely on proprietary tracking databases with varying security models and no cryptographic verification of package authenticity or delivery. QR codes on shipping labels can be easily copied, leading to fraud and misdirection of packages. DSPIP provides a cryptographic protocol specifically designed for shipping and logistics, enabling verification of package origin, custody chain, and delivery while protecting recipient privacy. The protocol addresses the fundamental challenge of QR code cloning through physical binding mechanisms and provides privacy-preserving delivery that reveals recipient information only to authorized last mile providers. By using the secp256k1 elliptic curve, DSPIP keys are compatible with major blockchain networks, allowing optional integration for immutable custody records while not requiring blockchain for basic operation. The protocol includes a type field set to "SHIP" for this specification, enabling future expansion to other applications. The design goals for DSPIP shipping protocol are:

• Cryptographic Authentication: Verify package origin and integrity through digital signatures
• Privacy Preservation: Protect recipient information during transit through encryption
• Anti-Cloning: Prevent QR code duplication through physical binding mechanisms
• Decentralized Verification: No central authority required for package validation
• Offline Capable: Verification possible without network connectivity
• Delivery Confirmation: Cryptographic proof of successful delivery
• Scalable Operations: Support high-volume shipping with efficient revocation and confirmation systems
• Standards Compliant: Integrate with existing logistics systems and standards
• Cost Effective: Near-zero marginal cost per package authenticated
• Blockchain Optional: Can integrate with blockchain but operates independently

DSPIP follows a "digital envelope" paradigm for shipping labels:

• Envelope exterior (publicly readable): Sender identity, last mile provider destination, tracking number, and timestamp are encoded but not encrypted. This functions like the address on a physical envelope.
• Signature (authenticity seal): A cryptographic signature proves the label was created by the claimed sender and has not been tampered with, similar to a shipping seal.
• Private contents (encrypted): The actual recipient address and delivery instructions are encrypted for the last mile provider, like the contents of a sealed package that only the authorized recipient can access.

This model protects recipient privacy while maintaining package routability and authenticity verification.

Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in when, and only when, they appear in all capitals, as shown here.

Relationship to Existing Standards DSPIP builds upon established standards while introducing novel shipping-specific features: Standards This Document Builds Upon:

• (DKIM): DSPIP adopts DKIM's DNS-based public key distribution model for shipping providers
• (PKCS #1): Uses established cryptographic specifications
• : Utilizes QR code standards for label encoding
• : Employs secp256k1 curve specifications (same curve as used by Bitcoin and Ethereum )
• : Elliptic Curve Integrated Encryption Scheme for recipient privacy
• : For split-key label authentication

Related Shipping Standards:

• : DSPIP adds cryptographic authentication to event- based visibility
• (ASN): DSPIP enables verification without central database
• Last Mile Standards: DSPIP adds encrypted routing for privacy

Novel Contributions:

• Privacy-Preserving Delivery: Encrypted recipient information with last mile provider routing
• Physical Anti-Cloning: Split-key labels with destructive reveal prevent QR code duplication
• Cryptographic Proof of Delivery: Challenge-response confirmation without key exposure
• Scalable Confirmation Systems: Bulk revocation and delivery lists for high-volume operations

Protocol Overview

Data Flow The DSPIP shipping protocol flow consists of the following steps:

1. Payload Creation: Sender creates a JSON payload containing sender information, last mile provider or recipient, tracking number, and timestamp
2. Privacy Selection: Choose privacy mode (standard, encrypted, or split-key) based on security requirements
3. Recipient Encryption: For privacy modes, encrypt recipient information with last mile provider's public key
4. Encoding: Payload is Base64 encoded to ensure consistent handling
5. Signing: Sender signs the data using their private key (or label's private key for split-key mode)
6. QR Generation: Complete data structure is serialized and encoded as a QR code
7. Label Application: QR code is printed on shipping label and attached to package
8. Transit Scanning: Carriers scan QR code at each custody transfer point
9. DNS Lookup: Scanner queries DNS TXT record to retrieve public key
10. Verification: Scanner verifies signature (or requests Zone B reveal for split-key)
11. Privacy Decryption: Last mile provider decrypts recipient information using their private key
12. Delivery: Package delivered to actual recipient address
13. Confirmation: Cryptographic proof of delivery recorded
14. Optional Blockchain: Custody chain recorded for audit trail

Protocol Workflow

DSPIP Shipping Flow | | 15. Delivery Confirmation | | |<======================== | | 16. Record Proof | ]]>

Data Formats

Payload Structure The payload contains shipping information encoded as JSON. Country codes use alpha-2 format:

SHIP Type Payload Fields The typeData object contains shipping-specific information including privacy mode, carrier details, customs information, and delivery confirmation settings.

Privacy Modes DSPIP supports three privacy modes for shipping:

Standard Mode (Legacy) Traditional shipping with full recipient information visible.

Encrypted Mode Privacy-preserving with encrypted recipient data. The recipient's address and delivery instructions are encrypted with the last mile provider's public key.

Split-Key Mode Maximum security with physical anti-cloning. Uses Ed25519 keys printed in separate scratch-off zones on the physical label.

QR Data Structure The complete QR code data structure contains:

• protocol: Fixed string "DSPIP"
• version: Semantic version string ("1.0")
• type: Fixed to "SHIP" for this specification
• keyLocator: DNS path for public key lookup
• encodedPayload: Base64-encoded JSON payload
• signature: Hex-encoded ECDSA signature
• privateMessage: Optional Base64-encoded encrypted message

Serialization Format QR data MUST be serialized using pipe (|) delimiters: ||||[|] ]]> The pipe delimiter was chosen for its low frequency in Base64 and domain names. Implementations MUST validate that exactly 6 or 7 pipe-delimited fields are present.

DNS Key Distribution DSPIP uses DNS TXT records for public key distribution, following the model established by DKIM .

Key Locator Format Key locators MUST follow this pattern: ._dspip. ]]> Where selector is a unique identifier for the specific key, _dspip is the fixed protocol subdomain (underscore prefix per ), and domain is the organization's domain name.

DNS TXT Record Format The DNS TXT record MUST contain a semicolon-separated list of tag=value pairs: ; [optional] ]]> Required tags: v (protocol version), k (key type), c (curve identifier), p (public key in Base64). Optional tags: t (creation timestamp), x (expiration), n (notes), types, auth, address, coverage.

Address Field Format The address field specifies the physical location of signing facilities using scheme prefixes:

• plus: (DEFAULT) Open Location Code / Plus Code
• street: Percent-encoded street address per
• geo: Geographic coordinates (latitude,longitude)
• facility: Named facility reference

If no scheme prefix is present, implementations MUST interpret the value as a Plus Code. See for the Open Location Code specification.

Selector Discovery Organizations MAY publish a discovery record at the base _dspip subdomain to enable discovery of available selectors.

Key Lifecycle Management DSPIP keys have a defined lifecycle to ensure security while maintaining verification capability for in-transit packages. Keys transition through states: Active (can sign and verify), Verify-Only (can only verify), and Expired (invalid). For shipping applications, the RECOMMENDED key lifetime is: Active signing period of 365 days, verify-only period of 365 additional days, for a total key lifetime of 730 days (2 years).

Record Signature (rsig) The rsig field provides cryptographic authentication of lifecycle metadata within the DNS record itself, protecting against unauthorized modification by intermediate DNS resolvers.

Key Revocation When a signing key is compromised or must be retired, organizations MUST have a mechanism to inform verifiers. The key revocation record provides a dedicated endpoint for key status.

Package Revocation Individual packages may need to be revoked due to loss, theft, or fraud. DSPIP provides individual revocation records and bulk revocation lists for scalability. Lists MUST be served over HTTPS and SHOULD auto-prune entries older than 180 days. Lists MAY use filters for privacy.

Delivery Confirmation Distribution Last mile providers MAY publish delivery confirmations via DNS TXT records pointing to confirmation endpoints.

Cryptographic Operations

Key Generation DSPIP uses the secp256k1 elliptic curve as specified in :

• Curve: secp256k1
• Private key: 256 bits (32 bytes)
• Public key: 264 bits (33 bytes compressed)

For split-key labels, is used with 256-bit keys.

Signature Creation Standard signature using ECDSA:

1. Construct signable content: signable = protocol | version | type | keyLocator | payload
2. Calculate SHA-256 hash of signable content
3. Sign hash using ECDSA with private key
4. Encode signature in DER format
5. Convert to hexadecimal string

Signature Verification Standard verification reconstructs signable content, calculates SHA-256 hash, retrieves public key from DNS, and verifies ECDSA signature. Split-key verification requires Zone B reveal and uses Ed25519 verification without DNS lookup.

Verification Process

Verification Algorithm Input: QR code data string. Output: Verification result with validity status.

1. PARSE: Split QR data by pipe delimiter, validate 6 or 7 fields present
2. VALIDATE PROTOCOL: Protocol MUST equal "DSPIP", Version MUST be compatible, Type MUST equal "SHIP"
3. DECODE PAYLOAD: Base64 decode and parse JSON
4. DNS LOOKUP: Query DNS TXT record for keyLocator
5. VERIFY SIGNATURE: Verify with public key
6. PRIVACY DECRYPTION: Decrypt encryptedRecipient if last mile provider
7. REVOCATION CHECK: Query revocation list
8. OPTIONAL BLOCKCHAIN: Record custody transfer

Privacy-Preserving Delivery Protocol The privacy-preserving delivery protocol protects recipient information during transit through ECIES encryption with the last mile provider's public key. Recipients are encrypted using ECIES over secp256k1 per :

1. Generate ephemeral key pair (r, R = rG)
2. Compute shared secret: S = r * LastMilePublicKey
3. Derive encryption key: K = KDF(S || R) using
4. Encrypt: C = AES-256-GCM(K, recipient_data) per
5. Output: R || C || tag

Physical Authentication via Split-Key Labels Split-key labels provide physical anti-cloning through two scratch-off zones containing Ed25519 key material. Zone A contains the private key (revealed at label creation), Zone B contains the public key (revealed at delivery verification).

Delivery Confirmation Protocol Cryptographic delivery confirmation uses challenge-response protocol where the recipient proves possession of their verification key.

Security Considerations DSPIP addresses the following shipping-specific threats:

• Package Forgery: Mitigated through cryptographic signatures
• QR Code Cloning: Prevented through split-key labels
• Recipient Privacy Breach: Protected through encryption
• Delivery Fraud: Cryptographic proof prevents false claims
• Package Tampering: Signatures detect modifications
• Replay Attacks: Unique tracking IDs prevent reuse
• Man-in-the-Middle: DNSSEC protects key lookups
• Tracking Attacks: Privacy modes prevent correlation

Shipping keys SHOULD use hardware security modules. Last mile providers MUST secure decryption keys. Organizations SHOULD rotate keys annually. Use encrypted mode for consumer deliveries. Limit address fields to necessary information. Comply with where applicable. Package revocation for lost/stolen items through individual records or bulk lists. SHIP entries expire after 180 days. Label manufacturing requires secure facilities, audit trails, no retention of private keys, and tamper-evident packaging.

IANA Considerations This document requests IANA to register the following:

1. Registration of "_dspip" in the "Underscored and Globally Scoped DNS Node Names" registry per
2. Reservation of "DSPIP" as a protocol identifier
3. Registration of DSPIP-specific DNS TXT record tags
4. Creation of DSPIP Type Registry with initial value SHIP
5. Creation of DSPIP Privacy Mode Registry (standard, encrypted, split-key)
6. Creation of DSPIP Authentication Profile Registry
7. Creation of DSPIP Key Revocation Reason Registry
8. Creation of DSPIP Item Revocation Reason Registry
9. Creation of DSPIP Delivery Confirmation Type Registry
10. Creation of DSPIP Key Status Registry
11. Creation of DSPIP Delegation Scheme Registry
12. Creation of DSPIP Address Scheme Registry

Normative References Standards for Efficient Cryptography Group Version 2.0 Journal of Computer Science and Engineering, Volume 2, Issue 2 Journal of Cryptographic Engineering, Volume 2, pp 77-89 Informative References ISO/IEC ISO/IEC 18004:2015 ISO ISO 3166-1:2020 GS1 Version 2.0 X12 ASC X12 Standard EDI 856 European Parliament and Council National Institute of Standards and Technology FIPS PUB 197 National Institute of Standards and Technology FIPS PUB 180-4 Google An open-source system for encoding geographic coordinates into a compact, URL-safe string. Communications of the ACM, Volume 13, Issue 7, pp 422-426

Test Vectors

Test Key Pair Private Key (hex): Public Key Compressed (hex): Public Key Base64 (for DNS):

Standard Mode Shipping Payload: Signature (DER-encoded ECDSA/secp256k1, hex):

Privacy Mode Shipping Recipient data (to be encrypted):

Split-Key Mode Label Serial: LABEL-2025-ABC123 Zone A Private Key (Ed25519, hex): Zone B Public Key (Ed25519, hex): Signature (Ed25519, hex):

DNS TXT Records Warehouse:

Revocation List

Implementation Guidelines

QR Code Generation Recommended settings:

• Error correction level M (15%) for standard labels
• Error correction level Q (25%) for split-key labels
• Error correction level H (30%) for outdoor use
• Automatic version selection
• Binary encoding mode

Performance Benchmarks Expected operation times:

• Key generation: 5-10 ms
• Signature creation: 2-5 ms
• DNS lookup: 20-100 ms (cacheable)
• Signature verification: 3-8 ms
• ECIES encryption: 10-20 ms
• ECIES decryption: 10-20 ms

Caching Strategy Key records follow standard DNS caching semantics with recommended TTL of 3600-86400 seconds. Revocation lists require stricter freshness controls with recommended refresh interval of 5-15 minutes. Large-scale logistics operations SHOULD implement centralized caching infrastructure.

Use Case Examples

E-commerce Order with Privacy Customer checkout flow with privacy-preserving delivery:

1. Customer enters address, selects preferred carrier
2. System retrieves carrier's public key, encrypts recipient
3. Label shows only carrier destination
4. Carrier decrypts at delivery, completes with proof

High-Value Package with Anti-Cloning Split-key label flow for valuable items:

1. Sender scratches Zone A, signs package, destroys private key
2. Package transits with unverifiable signature (cloning prevented)
3. Recipient scratches Zone B, reveals public key, verifies

Corporate Mailroom Delivery Internal routing with organizational keys:

1. Employee selects corporate mailroom as destination
2. System encrypts internal routing (dept, room number)
3. Mailroom decrypts and routes internally

International Shipping Cross-border delivery with customs compliance:

1. Customs info public, recipient encrypted
2. Customs verifies declarations, cannot see recipient
3. Local provider decrypts and completes delivery