ZEncrypt v0.1.0

ZEncrypt

Drag-and-drop file & folder encryption for people who don't want to touch a CLI.

Drop a file or folder, set a password, a keyfile, or a recipient's public key — get back a single authenticated .zsec archive. Decrypt it anywhere ZEncrypt runs. No cloud, no key servers, no accounts.

_{Tauri 2 · Rust · React 19 · ChaCha20-Poly1305 · AES-256-GCM · Argon2id · BLAKE3 · X25519}

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Screenshots

Idle drop zone — drag files or folders to encrypt, drop a .zsec to decrypt.	Encrypt screen — password or public-key mode, optional keyfile, cipher and KDF cost, compression toggle.
Decrypt screen — header preview shows cipher, KDF cost and keyfile fingerprint before you type anything.	Keyfile Manager — generate a 512-byte keyfile or an X25519 keypair, or inspect any key file's fingerprint.
Settings — defaults for cipher, KDF cost, chunk size, secure-delete, clipboard auto-clear, randomized output filename.

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Why ZEncrypt

Tool	Why it falls short for "encrypt this and send it"
VeraCrypt	Volume-based. Overkill for sharing a single file.
GPG	CLI-first, painful key management, terrible UX for non-experts.
7-Zip / WinRAR password	Not authenticated. Leaks filenames in the ZIP table.
age / rage	Great CLI, no GUI.
openssl enc	Nobody remembers the incantation.

ZEncrypt is the missing GUI: modern AEAD ciphers, real KDF, public-key support, drag-and-drop, no setup.

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Features

Three ways to encrypt Password — Argon2id-hardened, with a live entropy meter and a one-click generator. Keyfile — any file becomes a keyfile (512-byte CSPRNG generator built in). Mix with a password for two-factor decryption. Public key — X25519 keypair recipients (.zkey-pub / .zkey-priv). Share the public half anywhere; only the holder of the private half can decrypt.	Built for sharing, not for vaults One drag, one archive, one file to send. Filenames and folder structure live inside the encrypted payload — the outside leaks nothing. Open .zsec files by double-clicking (file association registered on install). Drag the finished archive straight out of the success screen into a chat or upload widget.
Modern, audited primitives AEAD: ChaCha20-Poly1305 (default) or AES-256-GCM. KDF: Argon2id — three presets, plus manual control. Integrity: per-chunk AEAD tags + a trailing BLAKE3 root over the full plaintext stream. Streaming: STREAM construction (Hoang–Reyhanitabar–Rogaway–Vizár) so truncation, reordering and chunk-substitution are all caught.	Honest UX Verify integrity without decrypting — useful before deleting an original. Progress + ETA + throughput, debounced cancel, atomic rename so a cancelled job leaves zero residue. Header preview before you type any password: see cipher, KDF cost, keyfile fingerprint, recipient fingerprint. Clear error buckets: "wrong credentials" looks different from "file corrupted."

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How encryption works (pick one)

Password mode — for personal archives and one-off shares where you can communicate the password out-of-band.

You type a password. ZEncrypt runs it through Argon2id (interactive / moderate / paranoid preset, or custom) to derive a 256-bit key. The recipient needs the same password to decrypt.

Strength matters. The UI shows a live entropy estimate. The built-in generator produces high-entropy passwords; the clipboard auto-clears after a configurable delay so the password doesn't linger.

Keyfile mode — for two-factor decryption or for completely password-free flows.

Any file can be a keyfile (binary, photo, song — doesn't matter). ZEncrypt hashes it with BLAKE3 and feeds that into Argon2id. You can use a keyfile alone, or combine it with a password — in which case both are required to decrypt, and a stolen password alone is useless.

The keyfile fingerprint (first 4 bytes of BLAKE3) is stored in the header so the recipient can verify they're using the right one before they even try a password.

Public-key mode — for "I want strangers to be able to encrypt files to me without sharing a secret first."

The recipient generates an X25519 keypair in the Keyfile Manager. They get two files:

• .zkey-pub — share it freely. Email it, tweet it, post it on your website. It can only encrypt, never decrypt.
• .zkey-priv — keep it secret. It is the only key in the universe that can open archives encrypted to its public half.

The sender picks the recipient's .zkey-pub in the encrypt screen, drops files, hits Encrypt. ZEncrypt generates a fresh ephemeral X25519 keypair per archive, does ECDH to derive a wrap key, encrypts the per-archive file key with ChaCha20-Poly1305, and embeds the ephemeral public key + wrapped file key in the header.

No password is involved on either side. No pre-shared secret. The recipient's fingerprint is shown in the header so the sender can verify they're encrypting to the right person.

Warning: losing your .zkey-priv permanently destroys access to every archive ever encrypted to its public half. There is no recovery. Back it up.

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The .zsec format

A .zsec file is a single binary blob with this layout:

+---------------------------+
| 63-byte plaintext header  |  magic + version + cipher + flags + KDF params + base nonce
+---------------------------+
| optional 4-byte keyfile   |  present when HAS_KEYFILE flag is set (v2+)
| fingerprint               |
+---------------------------+
| optional 88-byte pubkey   |  ephemeral X25519 pubkey + recipient fingerprint + wrapped key (v3+)
| block                     |
+---------------------------+
| chunked AEAD payload      |  [u32 chunk_len_with_flag][ciphertext || 16-byte tag], repeated
|                           |  high bit of length prefix marks the final chunk
+---------------------------+
| 32-byte BLAKE3 root       |  hash of pre-AEAD plaintext, defence-in-depth over per-chunk tags
+---------------------------+

Format version 3. The header is passed as AAD to every chunk, so any tampering with cipher choice, KDF params, or the pubkey block breaks all subsequent decryptions.

What an attacker with the file learns

• That it's a ZEncrypt archive (the magic bytes are public — this is true of every encrypted format).
• Roughly how big the plaintext was (from total file size, +/- chunk overhead and zstd compression).
• The cipher choice, KDF parameters, and (if pubkey mode) the recipient fingerprint.

That's it. Filenames, folder structure, file count, individual file sizes, and content are all encrypted inside the payload.

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What it can do

Area	Capability
Input	Drag files or folders onto the window Mix files and folders freely — they're packed into a single tar inside the archive File picker fallback (Open File / Open Folder) No size limit — everything streams Configurable chunk size (64 KiB / 256 KiB / 1 MiB)
Encrypt	ChaCha20-Poly1305 (default) or AES-256-GCM Argon2id with Interactive (~0.5s) / Moderate (~2s) / Paranoid (~5s) presets zstd compression on by default — automatically skipped for already-compressed extensions (jpg, mp4, zip, pdf, …) Optional secure-delete of source files after success: 1-pass, 3-pass DoD, or 7-pass Gutmann-lite Verify-then-delete: the new archive is integrity-checked before any source is touched
Decrypt	Header preview before typing any credentials Wrong-credentials error is distinct from corrupted-file error Verify integrity without writing plaintext to disk Live decryption progress with throughput + ETA
Reliability	Cancel any running job — partial files are cleaned up automatically Atomic rename: an interrupted encrypt never leaves a half-written .zsec posing as a complete one Cancel button has a confirmation step to prevent accidental clicks during long Argon2id derivations Single-instance enforcement — double-clicking a .zsec opens it in your existing window
History	Recent operations stored in a local SQLite database (WAL mode) One-click re-run from history...