Protocoldocs/protocol/security-model.md

Security model

Parano1d combines proof of work, recursive validity, exact Live State and signatureless wallet authorization. Each mechanism has a distinct job.

What consensus establishes

An accepted canonical tip establishes that:

  • its headers form the greatest-work eligible chain known to the node;
  • every accepted block preserves the hard-finalized prefix;
  • every wallet-authorized input belongs to a prover who knew the owner's 256-bit secret;
  • every input existed and every output target was empty in the exact parent State;
  • values, fees, issuance and allocation followed consensus;
  • the committed post-State is the exact result;
  • recursive validity reaches the current terminal.

Proof of work orders valid transitions. It does not repair invalid proofs. Recursive proofs establish validity. They do not replace fork choice.

Production soundness

The production profile has two distinct security statements. Block–Tiwari measures the classical random-oracle Fiat–Shamir compilation of FRI. The end-to-end theorem measures acceptance of an invalid recursive State by a quantum adversary.

Security statement Current production result
Target FRI security 128 bits
Provable Block–Tiwari FS-FRI security 127 bits
Conjectured Block–Tiwari FS-FRI security 127 bits
Sequential ideal-QROM half-success boundary 64.707407428576 bits
NIST Post-Quantum Cryptography Category Category 1
Dominant Category 1 gate-depth floor 173.391078499301 bits
Margin over the NIST 2^170 reference 3.391078499301 bits
Complete ideal bound at the Category 1 envelope 0.049330348228363684

Wallet analysis refinement

The W65 wallet uses a tighter Johnson-range analysis at radius 4/5, with at most 17 candidates at each Reed–Solomon layer. The resulting local bound is max(5^-65, 701202001931 / 2^255). The query term has a local exponent of 150.925326167679 bits, not an end-to-end post-quantum security level.

This is an analysis-only improvement. Query counts, matrices, proof formats and consensus are unchanged. The dominant resource term is now limited by history.query. The classical FS-FRI result, sequential ideal-QROM boundary and Category 1 classification remain unchanged. The wallet Johnson derivation gives the finite list bound, correlated-agreement argument and field-exception ledger using existing theorems valid in characteristic two.

Block–Tiwari FS-FRI

Block and Tiwari define concrete FS-FRI security as

text
log2(minimum expected classical random-oracle query work),

where the minimum ranges over every positive integer query budget. Applying their definitions, 256-bit random-oracle setting and whole-bit presentation to the production B25 and B255 profiles gives exact expected-work values in [127, 128) for both the provable and conjectured RBR premises. Their equality after integer presentation does not identify those premises.

The Block–Tiwari derivation proves the local RBR inputs for every production layer, solves both integer optimizations and reproduces the comparison with the systems in their published table.

End-to-end Category 1

The security game asks whether one stateful quantum adversary can make the production verifier accept an invalid terminal State whose recursive ancestry starts at genesis. One resource budget covers wallet authorization, the block relation, parent links, the exact State transition, recursive verification and every adversarial ancestor on which the terminal depends.

C1 is the source identifier for the production wide-challenge profile. It uses 65 wallet queries, 133 History queries, a 256-bit transcript digest and algebraic challenges sampled uniformly from a trace-one affine set of cardinality 2^255 in GF(2^256). Committed trace arithmetic and Poseidon2b remain over GF(2^128).

The depth-aware theorem evaluates all NIST Post-Quantum Cryptography Category 1 MAXDEPTH points against the AES-128 gate-depth reference 2^170. The base-two logarithm of its dominant half-success gate-depth floor is 173.391078499301 bits, and its complete ideal success bound at the Category 1 envelope is at most 0.049330348228363684.

The fixed Poseidon2b production corollary requires Delta_P2b^C1 < 0.450669651771636316. It also assumes the batch gate-depth price and minimum scalar gate charge stated by the resource theorem. Faster circuits may use more gates, so the reference-depth factor is not asserted as a universal minimum depth. Under these premises, the theorem gives provable end-to-end post-quantum soundness for state validation from genesis at NIST PQC Category 1: every adversary inside the Category 1 resource envelope has success probability below one half in the from-genesis invalid-State game.

The end-to-end QROM derivation states the game, reductions, finite terms and assumptions. The separate response accounting gives complete field and scalar constructions plus a scoped scalar lower bound; construction upper bounds are not substituted for declared resource prices. The noid_soundness certificate imports the production constants and evaluates every normative inequality with exact integer or rational arithmetic. This is a cryptographic Category 1 resource assessment, not a claim of NIST review or certification.

Trust boundaries

The protocol does not require:

  • a trusted proving setup;
  • a trusted snapshot publisher;
  • historical transaction-body archives for validation;
  • a public-key transaction signature scheme;
  • permission from seed nodes or peers.

The released binary embeds authenticated proof matrices. Snapshot State is checked against canonical headers and the matching terminal before installation.

Wallet boundary

The 256-bit master secret grants spending authority. Compromise of the device, secret file or original photo-derived material compromises the wallet. Consensus cannot distinguish the owner from an attacker who knows the same secret.

Receipts are local records, not derived secrets. Losing them does not lose funds, but can remove durable payment evidence after old block bodies are pruned.

Network boundary

Peer Ed25519 keys authenticate libp2p sessions only. They do not participate in wallet or block authorization. DNS seeds help locate peers but cannot define the canonical chain.

Connection diversity, message limits, staged synchronization and mempool budgets bound common resource attacks. Operators should still keep RPC on loopback, protect wallet files and use independent network paths for public infrastructure.

Transparency

Parano1d is not an anonymity system. Transaction owners, amounts, slots and fees are transparent while bodies are available. Zero knowledge hides the wallet secret and proves execution; it does not conceal the public ledger statement.

Finality assumption

Consensus refuses a reorganization that changes the prefix deeper than the 18-block finality boundary. Operators and applications may choose to wait for additional confirmations inside the recent suffix, but no peer can present a deeper branch as eligible under the same rules.

For operational protection, see Backup and recovery and Configuration. Consensus checks are collected in Consensus invariants.

ParanO(1)d technical documentationSource code defines consensus behavior.