Schiavinato Sharing (Python)

⚠️ WARNING: EXPERIMENTAL SOFTWARE ⚠️

DO NOT USE IT FOR REAL FUNDS!

Schiavinato Sharing specification and implementations have NOT been audited. Use for testing, learning, and experimentation only. See SECURITY for details.

We invite cryptographers and developers to review the spec and software. See CONTRIBUTING to know more.

Python implementation of Schiavinato Sharing: dual-mode (manual + software) (k)-of-(n) threshold secret sharing for BIP39 mnemonics over GF(2053). Designed for offline/air-gapped workflows, with manual-fallback compatibility.

What is this?

Schiavinato Sharing is a dual-mode (manual + software) (k)-of-(n) threshold secret sharing scheme for BIP39 mnemonics. It operates directly on the 1-indexed BIP39 word indices over the prime field GF(2053), so the recovered secret is a standard BIP39 mnemonic compatible with modern wallets.

In this Python implementation, you can:

• Split a BIP39 mnemonic into (k)-of-(n) shares (Share)
• Recover the original BIP39 mnemonic from (k) shares (RecoveryResult)
• Validate inputs and share integrity during split/recovery to prevent silent mistakes

Links

• Canonical protocol + specs: schiavinato-sharing
• Whitepaper: PDF (latest) | Releases (versioned PDF) | LaTeX
• Test Vectors: TEST_VECTORS
• Canonical security posture: SECURITY
• HTML implementation: schiavinato-sharing-html
• JavaScript implementation: schiavinato-sharing-js

Security

This library implements well-established cryptographic principles but has NOT been professionally audited.

Use only for: testing, learning, experimentation.

Canonical security posture: schiavinato-sharing/SECURITY

Verify Before Use (Required)

CRITICAL: Before using with real crypto seeds, verify the package and/or release artifacts haven't been tampered with.

Option A: Verify release artifacts (recommended for highest assurance)

This repository's releases include:

• CHECKSUMS-PYPI.txt (+ detached signature CHECKSUMS-PYPI.txt.asc)
• Python package artifacts (*.whl, *.tar.gz) (+ optional detached signatures *.asc)

Import the GRIFORTIS public key and verify signatures before use.

curl -fsSL https://raw.githubusercontent.com/GRIFORTIS/schiavinato-sharing-py/main/GRIFORTIS-PGP-PUBLIC-KEY.asc | gpg --import
gpg --fingerprint security@grifortis.com

Expected: 7921 FD56 9450 8DA4 020E 671F 4CFE 6248 C57F 15DF

Then verify release assets (examples):

gpg --verify CHECKSUMS-PYPI.txt.asc CHECKSUMS-PYPI.txt
sha256sum --check CHECKSUMS-PYPI.txt --ignore-missing

Option B: Verify the PyPI artifacts (supply-chain sanity check)

• Pin exact versions and use lockfiles for repeatable installs
• Prefer offline installs from a locally verified wheel/sdist

Installation

pip install schiavinato-sharing

Quick Start

Split a mnemonic

from schiavinato_sharing import split_mnemonic

mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
shares = split_mnemonic(mnemonic, 2, 3)
print(shares[0].share_number)

Recover a mnemonic

from schiavinato_sharing import recover_mnemonic

result = recover_mnemonic(shares[:2], word_count=12, strict_validation=True)
if not result.success:
    raise RuntimeError(str(result.errors))
print(result.mnemonic)

API Reference (high-level)

Stable entry points:

• split_mnemonic(mnemonic, k, n, wordlist=None)
• recover_mnemonic(shares, word_count, strict_validation=True, wordlist=None)

Advanced exports (field arithmetic, Lagrange helpers, checksum helpers, secure wipe utilities) are also available for integration/testing; see the package exports in schiavinato_sharing/__init__.py.

Conformance Validation

This implementation is validated against canonical test vectors:

• TEST_VECTORS

Functional Validation (Run Tests)

See TESTING for the full local testing checklist (CI parity).

Compatibility

• Spec version: v0.4.0
• Python: 3.10+

Contributing

See CONTRIBUTING.

License

MIT License