Cipher
AES-256-GCM encryption in your browser. Nothing is uploaded; the passkey never leaves this device.
Share the passkey with the other person by a different channel than the message itself.
Encrypted files are saved as
name.cipher. Large files are processed in memory; keep them under about 100 MB on phones.Format: PBKDF2-HMAC-SHA256 (600,000 iterations) key derivation, AES-256-GCM, random salt and IV per message. If the passkey is wrong or the data was altered, decryption fails.