Engyon: enprot

Enprot is a confidentiality processor for text and source code files. It lets you embed encrypted, stored, and authenticated segments directly inside any text-based file — source code, documentation, configuration — without breaking the host language's syntax.

• Human-editable markup: EPT directives sit inside host-language comments, so files stay valid C, Rust, Python, Markdown, HTML, or LaTeX.
• Content-addressed storage (CAS): segments can be sanitized out of the document and stored by their SHA3-256 hash. Same content always produces the same CAS file — deterministic, dedup-friendly.
• Authenticated encryption: AES-256-SIV (default), AES-256-GCM, or AES-256-GCM-SIV. Password-derived keys via Argon2, Scrypt, or PBKDF2. ML-KEM-based multi-recipient encryption via --recipient.
• Deterministic AEAD: optional aes-256-gcm-det / aes-256-gcm-siv-det variants derive the nonce from the plaintext so identical content always produces identical ciphertext — enabling CAS dedup on encrypted segments.
• Chain anchors: signed CHAIN blocks provide tamper-evident file history. Multi-signer anchors require N parties to sign.
• Merge-friendly: WORD-region merge driver emits CONFLICT blocks that keep the file valid host-language source. enprot resolve clears them. CAS-referenced blocks deduplicate across branches.
• Post-quantum ready: ML-DSA signatures, ML-KEM key encapsulation, and composite Ed25519+ML-DSA constructions ship today.

Installation

From crates.io

cargo install enprot

From source

Enprot requires Botan 3.x (brew install botan on macOS; see ci/install.sh for Linux).

cargo install --git https://github.com/engyon/enprot

or build locally:

git clone https://github.com/engyon/enprot
cd enprot
cargo build --release        # binary at target/release/enprot

Shell completions

After installation, generate completions for your shell:

enprot completions bash  > /etc/bash_completion.d/enprot
enprot completions zsh   > ~/.zsh/completions/_enprot
enprot completions fish  > ~/.config/fish/completions/enprot.fish
enprot completions powershell | Out-File enprot.ps1

Quick start

mkdir cas                                               # CAS storage directory
enprot init                                             # config + cas/ + .gitattributes
enprot encrypt -w Secret -k Secret=password file.txt    # encrypt inline
enprot decrypt -w Secret -k Secret=password file.txt    # decrypt
enprot store  -w Secret file.txt                        # sanitize to CAS
enprot fetch  -w Secret file.txt                        # restore from CAS
enprot list   file.txt                                  # see segments
enprot inspect file.txt                                 # structure + anchors + capabilities
enprot verify file.txt                                  # check integrity

EPT markup

An EPT file is a normal text file containing directives hidden inside host-language comments. The default separators are // <( (left) and )> (right), which work for C, C++, Rust, JavaScript, and other //-comment languages.

A simple example (sample/test.ept):

hello, this is a test file
// <( BEGIN GEHEIM )>
Secret line 1
Secret line 2
// <( BEGIN Agent_007 )>
James Bond
// <( END Agent_007 )>
// <( END GEHEIM )>
// <( BEGIN Agent_007 )>
Super secret line 3
// <( END Agent_007 )>

Directive types:

Host-language separators

Use -l/-r to override the separators for non-// languages, or use the --lang preset:

Example: encrypt a Python file's segments with # <( comments:

enprot --lang python encrypt -w Secret -k Secret=pw script.py

Subcommands

encrypt

Encrypt WORD segments inline (ciphertext stays in the document):

enprot encrypt -w Agent_007 -k Agent_007=bond sample/test.ept

If no -k is given, you are prompted interactively (with repeat).

Encrypt-specific options (run enprot encrypt --help for the full list):

decrypt

Decrypt WORD segments:

enprot decrypt -w Agent_007,GEHEIM -k Agent_007=bond -k GEHEIM=james sample/test.ept

Multiple WORDs are comma-separated or repeated. Multiple -k flags supply passwords for different WORDs.

For KEM-mode blocks (encrypted with --recipient):

enprot decrypt -w Agent_007 --key-file priv.pem sample/test.ept

store

Sanitize WORD segments to CAS — replace the segment content with a STORED <WORD> <hash> pointer and write the original content to a file named by its SHA3-256 hash:

enprot store -w GEHEIM sample/test.ept

After storing, the CAS directory contains the content:

$ ls cas
cea67c3ef34ff899793b557e9178c1b97bbcfe9722df2f6d35d2d0c91d2c1fe4

The same content always produces the same hash, so storing is idempotent — re-storing identical content is a no-op.

fetch

Restore WORD segments from CAS:

enprot fetch -w GEHEIM sample/test.ept

encrypt-store

Encrypt and store in one step. The ciphertext goes to CAS and is referenced by hash:

enprot encrypt-store -w Agent_007 -k Agent_007=bond sample/test.ept

verify

Check file integrity without decrypting. Validates markup structure, CAS pointer resolution (file exists + hash matches), and extfield formatting:

enprot verify sample/test.ept
enprot verify *.ept

Output is OK or FAIL per file. Exits non-zero on any failure — useful in CI pipelines.

list

List all WORD segments in a file with their type and crypto metadata:

$ enprot list sample/test.ept
BEGIN/END  GEHEIM
  BEGIN/END  Agent_007
  ENCRYPTED Agent_007  cipher=aes-256-siv  pbkdf=legacy
BEGIN/END  Agent_007
  ENCRYPTED Agent_007  cipher=aes-256-siv  pbkdf=legacy

For multiple files, each is headed with == <path> ==.

passthrough

Parse and re-write a file without applying any transform. Useful for validating markup or measuring parse performance:

enprot passthrough sample/test.ept

completions

Print a shell completion script:

enprot completions bash  > /etc/bash_completion.d/enprot
enprot completions zsh   > ~/.zsh/completions/_enprot
enprot completions fish  > ~/.config/fish/completions/enprot.fish
enprot completions powershell | Out-File enprot.ps1

inspect

Combined diagnostic: show structure + chain anchors + conflicts + capabilities in one pass (exit non-zero if conflicts remain):

enprot inspect sample/test.ept

keygen / sign / verify-sig

Detached signatures (Ed25519, ML-DSA, and composite constructions):

# Generate a keypair (PEM, one file each).
enprot keygen ed25519 --out-priv priv.pem --out-pub pub.pem

# Sign a file → produces FILE.sig (raw 64-byte Ed25519 signature).
enprot sign --alg ed25519 --key-file priv.pem document.txt

# Verify → reads document.txt.sig by default.
enprot verify-sig --alg ed25519 --key-file pub.pem document.txt

Multi-signer bundles (repeat --key-file):

enprot sign --alg ed25519 --key-file priv1.pem --key-file priv2.pem document.txt
enprot verify-sig --alg ed25519 --key-file pub1.pem --key-file pub2.pem document.txt

Override the signature path with --sig-file PATH (verify-sig) or -o PATH (sign). Both commands read stdin when no FILE is given.

Chain anchors

Signed chain anchors provide tamper-evident file history:

# Produce an anchor after a transform.
enprot encrypt --anchor --signer priv.pem -w WORD -k WORD=pw file.ept

# Verify anchors against a trusted pubkey.
enprot verify-chain --trust-root pub.pem file.ept

# Print the current chain head hash (publish out-of-band).
enprot snapshot file.ept

# Verify against a published pin.
enprot pin <expected-hash> file.ept

# List unresolved conflicts (exit non-zero if any).
enprot conflicts file.ept

Merge driver + conflict resolution

# Git merge-driver contract (%O=ancestor, %A=ours, %B=theirs, %P=path).
enprot merge-driver %O %A %B %P

# Resolve conflicts (one mode for all, or per-WORD overrides).
enprot resolve --mode ours file.ept
enprot resolve --word Agent_007:ours --word GEHEIM:theirs file.ept

Git filters

enprot init --git    # writes .gitattributes + prints .git/config snippet

# stdin → stdout pipes for git filter/textconv integration.
enprot clean  -w WORD -k WORD=PASSWORD   # plaintext → ciphertext
enprot smudge -w WORD -k WORD=PASSWORD   # ciphertext → plaintext

Provenance + supply chain

# SLSA-style provenance manifest.
enprot manifest . --output build.ept -c cas/
enprot attest --signer builder.pem build.ept
enprot verify-chain --trust-root builder.pub build.ept

# Supply-chain manifest with Cargo.toml dep parsing.
enprot scm init manifest.ept
enprot scm add manifest.ept src/
enprot scm deps manifest.ept Cargo.toml
enprot scm attest --signer vendor.pem manifest.ept
enprot scm verify --trust-root vendor.pub manifest.ept
enprot scm diff old.ept new.ept

Common options

These flags work with every subcommand (before or after the subcommand name):

Deterministic encryption

By default, AES-GCM and AES-GCM-SIV use random nonces — encrypting the same plaintext twice produces different ciphertexts. This breaks CAS deduplication for encrypted segments.

The -det cipher variants derive the nonce from the plaintext via HKDF + HMAC, making encryption fully deterministic:

Same (password, plaintext) always produces the same ciphertext, so encrypt-store on identical segments deduplicates in CAS.

Usage:

enprot encrypt -w Agent_007 --cipher aes-256-gcm-det -k Agent_007=bond file.ept

Multi-file processing

Process wildcards in one invocation. Passwords are prompted once:

enprot encrypt -w Secret -k Secret=pw src/*.rs

Output to a different file:

enprot encrypt -w Secret -k Secret=pw input.ept -o output.ept

Output to a directory (basename preserved):

enprot encrypt -w Secret -k Secret=pw --output-dir build/ src/*.ept
# or equivalently:
enprot encrypt -w Secret -k Secret=pw -p build/ src/*.ept

Plain prefix (prepended verbatim — legacy behavior):

enprot encrypt -w Secret -k Secret=pw -p build_ src/*.ept
# produces: build_src/main.ept, build_src/lib.ept, …

Working on source code

EPT directives inside comments don't break compilation. Enprot's own source has an encrypted AUTHOR block in src/lib.rs:

// <( ENCRYPTED AUTHOR )>
// <( DATA X417HVMRRAs6Z1xGo5yY4TxUQ2tpAHEKQ1sg9+kfku5uUikK3y2tODtsUiGqfRGW )>
// <( DATA xUCGYFu02BCdqPM7uuX5UNvbfrLvKkj6gLYwg/cr42PJmr4o5xnw1qo= )>
// <( END AUTHOR )>

Decrypt it:

enprot decrypt -w AUTHOR -k AUTHOR=markku src/lib.rs

Crypto policies

Two built-in policies control which algorithms are permitted:

--fips forces the nist policy. On Linux, it also auto-engages when /proc/sys/crypto/fips_enabled reads 1.

See docs/fips.adoc for details on what a fully FIPS-validated build would require.

Compatibility

Documents encrypted by enprot <=0.3.1 still decrypt. The wire format of the pbkdf: and cipher: extended fields is unchanged:

// <( ENCRYPTED <keyword> [cas-hash] pbkdf:$<id>$<k=v,k=v>$<base64-salt> cipher:$<alg>$iv=<base64-iv> )>

When the ciphertext is in CAS rather than inline, the CAS hash replaces the inner DATA lines and the cipher: field carries the IV.

The legacy PBKDF (plain SHA3-512 truncation) is retained for decrypting old blobs; selecting it for new encryption prints a warning.

See docs/migration-0.3-to-0.4.md for the full migration guide (subcommand CLI, CAS-referenced default, CONFLICT directive, chain anchors, feature-gated library).

Configuration

enprot init writes .enprot.toml. Layered resolution:

1. Built-in defaults
2. ~/.config/enprot/config.toml (user global)
3. .enprot.toml (project local, walked up from cwd)
4. ENPROPT_* environment variables
5. CLI flags (highest precedence)

casdir = "cas"
lang = "c"

[encrypt]
cipher = "aes-256-gcm-siv-det"
pbkdf = "argon2"

[chain]
# signer = "confium://session-id"
# auto_anchor = true

Library usage

Enprot can be used as a Rust library without the CLI:

[dependencies]
enprot = { version = "0.4", default-features = false }

The default-features = false build excludes clap and clap_complete. All library modules (crypto, parsing, capability model, chain anchors, Merkle trees, merge driver, provenance, SCM) are available.

Development

See CONTRIBUTING.md for the full guide. Quick reference:

cp .githooks/pre-commit .git/hooks/pre-commit && chmod +x .git/hooks/pre-commit
cargo test
cargo fmt --all --check
cargo clippy --all-targets -- -D warnings
typos                    # spell check (cargo install typos-cli)
cargo deny check         # license + advisory check

Architecture docs: CLAUDE.md. Wire format specs: docs/schemas/. Upgrade history: TODO.upgrade/, TODO.audit/, TODO.issues/, TODO.finalize/, TODO.roadmap/.

License

BSD-2-Clause. See LICENSE file.