YPC-27 Checksums | YAKMESH Documentation

Overview

YPC-27 is a quantum-hard checksum algorithm that protects YAKMESH packets from forgery. Unlike traditional CRC or hash-based checksums, YPC-27 operates in balanced ternary space using a 27-trit polynomial ring.

Forging a YPC-27 checksum requires solving the Short Integer Solution (SIS) problem — the same hard problem that underpins lattice-based post-quantum cryptography.

27

Trits

7.6T

Possible States (3²⁷)

SIS

Hardness Basis

Why 27 Trits?

Mathematical Properties

• 27 = 3³ — perfect cube in the ternary domain
• 3²⁷ ≈ 7.6 trillion possible checksum values
• Ring structure: Z[x]/(x²⁷-1) mod 3
• Polynomial operations provide algebraic mixing (avalanche)

Security Properties

• Avalanche effect: Single bit flip → all 27 coefficients change
• SIS hardness: Finding two messages with same checksum = solving SIS
• Domain separation: Same data → different checksums per protocol
• Quantum resistant: No known quantum speedup for SIS

Balanced Ternary

YPC-27 uses balanced ternary with values {-1, 0, +1}:

T

-1 (negative)

0

0 (neutral)

1

+1 (positive)

Example checksum: 1T011T0... (27 trits total)

Usage

Basic Checksum

import { computeYpc27, verifyYpc27 } from 'yakmesh/oracle/ypc27';

// Compute checksum for any data
const data = { message: 'Hello, YAKMESH!' };
const checksum = computeYpc27(data);
// → { trits: Int8Array(27), base64: 'YXBj...', hex: 'abc123...' }

// Verify checksum
const isValid = verifyYpc27(data, checksum);
// → true

Domain-Separated Checksums

import { 
  createStupaChecksum,
  createNakpakChecksum,
  createKhataChecksum 
} from 'yakmesh/oracle/packet-checksum';

// Same data, different domain → different checksums
const data = { content: 'test' };

const stupaChecksum = createStupaChecksum(data);
const nakpakChecksum = createNakpakChecksum(data);
const khataChecksum = createKhataChecksum(data);

// All three are different! (domain separation)
console.log(stupaChecksum !== nakpakChecksum); // true

Wrap & Unwrap Helpers

import { wrapWithChecksum, unwrapWithChecksum } from 'yakmesh/oracle/packet-checksum';

// Wrap data with checksum
const wrapped = wrapWithChecksum(myData, 'STUPA');
// → { data: myData, ypc27: 'YPC27:v1:abc123...' }

// Unwrap and verify
const { data, valid } = unwrapWithChecksum(wrapped, 'STUPA');
if (!valid) {
  console.error('Checksum mismatch - packet may be corrupted or tampered!');
}

Wire Format

YPC-27 checksums use a versioned wire format:

YPC27:v1:<base64-encoded-trits>

Part	Description	Example
`YPC27`	Algorithm identifier	`YPC27`
`v1`	Version (for future algorithm updates)	`v1`
`<trits>`	Base64-encoded 27 trits	`YXBjZGVm...`

Protocol Integrations

STUPA Broadcasts

Beacon messages now include ypc27 field. Verified on deserialize.

mesh/beacon-broadcast.js

NAKPAK Packets

Routed packets include checksum. Computed during padToFixedSize().

mesh/nakpak-routing.js

KHATA Protocol

ANNOUNCE, REQUEST, RESPONSE, REVOKE messages all include checksums.

security/khata-protocol.js

SHERPA Discovery

Peer discovery messages protected against tampering.

mesh/sherpa-discovery.js

Security Analysis

Attack Resistance

Attack	Difficulty	Notes
Brute Force	3²⁷ ≈ 7.6T operations	Infeasible for online attacks
Collision (Classical)	SIS-Hard	Requires solving lattice problem
Collision (Quantum)	No known speedup	SIS believed quantum-resistant
Cross-Protocol Replay	Prevented	Domain separation ensures uniqueness

API Reference

oracle/ypc27.js

Export	Description
`computeYpc27(data)`	Compute 27-trit checksum for any data
`verifyYpc27(data, checksum)`	Verify checksum matches data
`tritsToBase64(trits)`	Convert trit array to Base64 string
`base64ToTrits(b64)`	Convert Base64 string to trit array

oracle/packet-checksum.js

Export	Description
`wrapWithChecksum(data, domain)`	Wrap data with domain-separated checksum
`unwrapWithChecksum(wrapped, domain)`	Unwrap and verify checksum
`createStupaChecksum(msg)`	STUPA-domain checksum
`createNakpakChecksum(pkt)`	NAKPAK-domain checksum
`createKhataChecksum(msg)`	KHATA-domain checksum

Version History

Version	Changes
v2.7.1	Initial release of YPC-27 checksums with STUPA, NAKPAK, KHATA integrations