Where the boundary is drawn.
SLIK protects one thing well: the contents of the files you keep in it. This page says exactly what that covers, what it does not, and how a file is unlocked again.
File contents
File contents are encrypted by the native client with AES-256-GCM before upload and decrypted on your device when you open them. Encryption and decryption happen on the machine you are sitting at. We store ciphertext, so we cannot read your files, and neither can the storage provider underneath us.
File-content encryption is distinct from account information, service metadata, and the local search index. Those are covered below and in the privacy policy.
The unlock chain
Four steps stand between the ciphertext on disk and a readable file. Each one lives on your device.
Recovery phrase
A BIP39 phrase generated on your device. It is the root of your keys. If you lose it and lose your devices, we cannot recover your files for you.
Secure Enclave
Apple hardware on your Mac holds key material that unwraps your keys locally. It does not leave the device and it is not sent to us.
Passcode
A four-character passcode unlocks SLIK for a session. It gates the local unwrap; it is not the encryption key itself and it is not a password we store.
Decryption
Content is decrypted in the app as you open it. Plaintext exists in memory while you are working with a file, not in your storage folder.
Agents, scripts, and anything else with read access
A process that can read your filesystem reads plaintext wherever plaintext is sitting: sync folders, Desktop, Downloads, project directories. That includes tools you deliberately installed and granted broad permissions to — coding agents, MCP servers, package postinstall scripts — as well as things you did not install on purpose.
Files kept in SLIK are not readable that way. What is on disk is ciphertext, and opening it requires the unlock chain above. That reduces how much a single over-permissioned process can walk away with. It is a smaller blast radius, not an antivirus product.
What SLIK does not do
- It does not detect, scan for, block, quarantine, or remove malware.
- It does not sandbox, block, or monitor AI agents or any other process on your machine.
- It does not protect files that live outside SLIK. Anything left in an ordinary folder stays as readable as it was.
- It does not help against an attacker who controls your machine while SLIK is unlocked. At that point they can read what you can read.
- It does not claim independent security certification or an audit of the complete service. SLIK is in development.
The local search index
Search runs on your device against a local index. That index can contain filenames and text extracted from your files, and it is separate from the encrypted uploads. It is one more reason that protecting the device itself — FileVault, screen lock, careful permissions — stays part of protecting your files.
Reporting a vulnerability
If you find a security issue, email security@slik.so with enough detail to reproduce it. We read every report and will tell you what we are doing about it. Please give us a chance to fix an issue before publishing it.
Contact
Rainbow Labs Inc.
2261 Market Street #5460
San Francisco, CA 94043
Security questions: support@slik.so
Vulnerability reports: security@slik.so