1seed

Deterministic cryptographic keys (and other derivations) from a single seed.

What This Does

• Stores seed securely in OS keychain with automatic fallback to ~/.1seed
• Derives age, SSH, and signing keys from one master secret
• Encrypts and decrypts files using age
• Signs and verifies data using Ed25519
• Generates site-specific passwords, deterministic integers, UUIDs, and BIP39 mnemonics

Installation

# From crates.io
cargo install oneseed

# From source
git clone https://github.com/oeo/1seed && cd 1seed
make install

# Generate man page and shell completions
make generate

Quick Start

1seed init --generate              # Initialize master seed
1seed age pub                      # Show public key
1seed ssh add                      # Add SSH key to agent
echo "secret" | 1seed age encrypt  # Encrypt to self
1seed derive password github.com   # Generate password
1seed status                       # Check status

Seed Storage

Priority: --seed-file flag → SEED_FILE env → OS keyring → ~/.1seed.

1seed uses OS-native credential stores (Keychain, Secret Service, Credential Manager) where available. If unavailable, it automatically falls back to ~/.1seed (mode 0600).

# Override seed location
SEED_FILE=/path/to/seed 1seed age pub

# Set default realm
export SEED_REALM=work

Storage format: init stores the 32-byte derived master seed prefixed with the magic bytes 1SED2. File fallback writes mode 0600. Seeds written before this header existed are still readable: a seed with no header is interpreted exactly as before (raw 32-byte binary, or passphrase text). Derived keys are unchanged when re-running init with the same passphrase — except one legacy case: passphrases of 32+ bytes containing non-ASCII characters were previously misread as raw binary; re-initializing such a seed changes its derived keys.

Commands

Initialization

• 1seed init [-g | -p | --from-file FILE] : Store seed (generate random, passphrase, or file).
• 1seed forget --confirm : Remove seed from all storage.
• 1seed status : Show seed location and public keys.

Age Encryption

• 1seed age [pub | key] : Show keys.
• 1seed age encrypt [-s] [-a] [-o FILE] : Encrypt (default to self).
• 1seed age decrypt [-k FILE] [-o FILE] : Decrypt using derived key.

SSH & Signing

• 1seed ssh [pub | key | add] : SSH key management and agent integration.
• 1seed sign [pub | data | verify] : Ed25519 signatures.

Derivation

• 1seed derive password SITE [-l 16] [-n 1] : Site-specific passwords.
• 1seed derive int PATH [--min 0] [--max 2147483647] : Deterministic integers.
• 1seed derive uuid PATH : Deterministic UUIDs.
• 1seed derive mnemonic [-w 24] : BIP39 word phrases.
• 1seed derive raw PATH [-l 32] [--hex | --base64 | --binary] : Deterministic raw bytes (max 8160).

Realms

Realms namespace all derived keys. Same seed, different realm = different keys.

1seed --realm work ssh add
export SEED_REALM=personal

Security Model

Single Point of Failure: The seed is the "Master Key". If it leaks, everything derived from it is compromised. 1seed trades N secrets for one well-protected secret.

• Storage: Uses OS-native credential stores (Keychain, Secret Service, Credential Manager) where available. These are software credential stores, not hardware-backed (no Secure Enclave or TPM); treat the stored seed with the same care as a password file.
• KDF: HKDF-SHA256 for derivation; scrypt for passphrases (~1GB RAM).
• Memory: Derived keys are zeroized when dropped.

Version History

• v0.8.0: Added --seed-file, upgraded age to 0.12, refreshed audited dependencies
• v0.7.0: Upgraded age crate to 0.11, expanded age encryption test coverage
• v0.6.0: Removed self-update, added man page and fuzz targets
• v0.5.2: Code formatting fixes
• v0.5.1: Deterministic Integer and UUID derivation, improved documentation
• v0.5.0: Auto-fallback to ~/.1seed, SEED_NO_KEYRING env var
• v0.4.0: Keyring-only storage, removed config file
• v0.3.0: Simplified config
• v0.2.0: Domain-based namespaces (age, ssh, sign, derive)
• v0.1.0: Initial release

License

MIT