sigil

Quantum-safe signing and key migration for blockchain developers.

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The Problem

Every blockchain wallet uses ECDSA signatures. Shor's algorithm running on a sufficiently large quantum computer breaks ECDSA in polynomial time. Google's March 2026 paper showed Bitcoin keys are breakable with under 500,000 physical qubits — 20x fewer than previous estimates.

NIST finalized post-quantum cryptographic standards in 2024 (FIPS 203, 204, 205).

The migration problem nobody has solved cleanly: How does an existing blockchain user migrate from ECDSA to a quantum-safe key without losing assets, without a hard fork, and with an on-chain verifiable proof?

sigil solves this.

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What sigil Does

# Generate a quantum-safe keypair
sigil keygen --algo ml-dsa --out keypair/

# Sign a transaction
sigil sign --key keypair/priv.key --in tx.json --out tx.sig

# Verify a signature
sigil verify --key keypair/pub.key --in tx.json --sig tx.sig

# Migrate from ECDSA to ML-DSA — the command that didn't exist
sigil migrate --from ecdsa.key --chain ethereum --out migration_proof.json

# Benchmark all algorithms
sigil bench

The migrate command is the core differentiator:

1. Reads your existing ECDSA private key
2. Generates a corresponding ML-DSA keypair deterministically
3. Outputs a migration proof — the new PQC public key signed with the old ECDSA key
4. SigilMigration.sol verifies this proof on-chain and records the key mapping permanently
5. Future transactions use the PQC key. The old key can be retired.

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Architecture

sigil/
├── core/                  # Pure C — zero dependency crypto engine
│   ├── sha256.c/h         # SHA-256 from FIPS 180-4
│   ├── hmac.c/h           # HMAC-SHA256 from RFC 2104
│   ├── merkle.c/h         # Merkle tree with proof generation
│   ├── wots.c/h           # WOTS+ from Hülsing 2017
│   ├── xmss.c/h           # XMSS-lite from RFC 8391
│   ├── sigil_sign.c/h     # Unified signing API (crypto agility)
│   ├── sigil_migrate.c/h  # Migration proof generation
│   └── pqc_rand.c/h       # Cryptographic random from /dev/urandom
├── src/                   # Rust CLI layer
│   ├── main.rs
│   └── commands/          # keygen · sign · verify · migrate · bench
├── contracts/             # Solidity on-chain verifier
│   ├── SigilVerifier.sol  # Verifies PQC signatures on-chain
│   ├── SigilMigration.sol # Records ECDSA → PQC key migrations
│   └── SigilWallet.sol    # ERC-4337 quantum-safe wallet
├── ffi/                   # Rust bindings to C core
├── scripts/               # ethers.js deployment scripts
├── tests/                 # Test vectors and integration tests
├── benchmarks/            # criterion benchmarks
└── docs/                  # Architecture diagrams, API reference

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Why Zero Dependencies

The C core has zero external dependencies. Every cryptographic primitive is implemented from its primary specification:

Primitive	Specification
SHA-256	NIST FIPS 180-4
HMAC	RFC 2104
WOTS+	Hülsing 2017 (eprint.iacr.org/2017/965)
XMSS-lite	RFC 8391
ML-DSA	NIST FIPS 204

Zero dependencies means zero supply chain attack surface. You can audit every line.

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Crypto Agility

sigil builds algorithm agility in from day one — one function, any NIST PQC algorithm:

sigil_sign(key, msg, SIGIL_ML_DSA);   // FIPS 204
sigil_sign(key, msg, SIGIL_SLH_DSA);  // FIPS 205
sigil_sign(key, msg, SIGIL_XMSS);     // RFC 8391

When NIST adds new algorithms, sigil supports them without breaking existing users.

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Benchmarks

*Updated weekly.

Operation	sigil	OpenSSL ECDSA	Ratio
keygen	TBD	TBD	TBD
sign	TBD	TBD	TBD
verify	TBD	TBD	TBD
migrate	TBD	N/A	N/A

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Security

sigil is under active development. Do not use in production until v1.0.0.

Security issues: see SECURITY.md To report a vulnerability: email:gaurishb.dev@gmail.com or open a GitHub Security Advisory.

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License

sigil is dual licensed:

• Open source use: GPL v3 — free for open source projects
• Commercial use: Commercial License — required for proprietary products

For commercial licensing: gaurishb.dev@gmail.com

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Status

Week	Milestone	Status
1	v0.0.1 — Repo skeleton, XOR cipher, random	🔄 In Progress
2	v0.0.2 — SHA-256, all NIST vectors	⏳ Planned
3	v0.0.3 — Merkle tree, proofs	⏳ Planned
4	v0.0.4 — Wasm bridge, CLI hash	⏳ Planned
5	v0.1.0 — WOTS+ complete	⏳ Planned
6	v0.2.0 — XMSS-lite complete	⏳ Planned
7	v0.3.0 — Solidity verifier on Sepolia	⏳ Planned
8	v0.4.0 — sigil migrate + demo video	⏳ Planned
9	v0.5.0 — Rust CLI complete	⏳ Planned
10	v1.0.0 — Published on crates.io	⏳ Planned

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Started: April 22, 2026. Building in public.