Five guarantees about your data
Security claims are only useful when they are specific. These are the five properties ArShield is built to preserve, and how each one is enforced.
We cannot see your data
Encryption and decryption happen in your browser. File contents, filenames, keys, and message plaintext never reach us.
No custody, no control
ArShield has no ability to decrypt, access, or modify your files at any time. There is no server that processes your data.
Keys never leave your device
Key material is derived and used locally, in your browser. If you lose your wallet, key file, and passphrase, your encrypted files are unrecoverable. This is by design.
Authenticated and tamper-evident
AES-256-GCM binds ciphertext to its metadata through an authentication tag, and ML-DSA-65 signs the whole envelope. Any modification is detected at decrypt time.
NIST-standardized primitives
ML-KEM-768 (FIPS 203), ML-DSA-65 (FIPS 204), X25519 (RFC 7748), and AES-256-GCM. No experimental or home-rolled cryptography.
What this means in practice
Because there is no server holding your data, there is no breach surface for your files. The privacy policy lists the only records that ever touch a disk: a count of today's encryptions in local storage, a first-use signing flag per wallet, and the wallet connection your wallet library keeps. Nothing else, and no signature or key, is stored.
Reporting a vulnerability
If you believe you have found a security issue, email hello@arc-shield.xyz. Please include reproduction steps and, where possible, a minimal proof of concept.