BitCipher File Encryption - Xinghui Shudun | Local AES-256 | Free

BitCipher encrypts text and files right in your browser's side panel. Nothing leaves your computer: no network, no account, no upload. Your files and your passphrase stay on this device. WHO IT IS FOR - You send contracts, reports or ID scans by email, cloud drive or chat and want only the person with the passphrase to open them - You need to drop a piece of ciphertext into a note, a ticket or a message that the recipient can restore on any device - You want an encryption tool that needs no cloud service, no sign-up, and can be audited NOTHING FOR THE RECIPIENT TO INSTALL - Open shudun.bitbeam.cn/cipher/open, pick the file, enter the passphrase — works in any browser, phones included; decryption stays local there too - A Python command-line tool reads the same format on servers TEXT - Type text, enter a passphrase, press the button: you get a ciphertext starting with SDX: that you can paste anywhere - Paste a ciphertext back and the button switches to Decrypt on its own - Decrypted text you copy is cleared from the clipboard after 30 seconds - Select text on any page and right-click "Encrypt / decrypt selection with BitCipher" to send it straight to the side panel FILES - Drop files of any type and any size; encryption is streamed with a live progress bar - The output is an .sdx container; the file name is encrypted together with the content, so nothing about the file is visible from outside. Turn on "Hide file name" and the output name becomes a random string too — the original is still restored on decrypt - .sdx files are recognised and decrypted automatically; the original name is restored. Single files can be written straight to a location you choose STRENGTH - AES-256-GCM authenticated encryption: any tampering, truncation or reordering is rejected - Argon2id passphrase derivation (64 MiB memory, 3 passes) resists GPU brute force - Built-in passphrase generator and a four-level strength meter - Files encrypted by earlier versions still open SDX CONTAINER - The ciphertext carries every parameter needed to decrypt it (algorithm, salt, chunk size), so it does not depend on this extension - Suitable for long-term archives and hand-offs between teams PERMISSIONS AND PRIVACY - No access to any website, no injected scripts, no reading of page content - Only clipboard write (copying results), clipboard read (used solely to confirm that the auto-clear is removing text this extension wrote), the side panel and a context menu item (reads the selection only when you click it) - No telemetry, no analytics, no third-party scripts; all code ships inside the package, nothing is loaded remotely - Follows your browser's language and dark mode NOTE The passphrase is never stored and cannot be recovered. Share it with the recipient over a different channel than the file — for example the file by email, the passphrase by phone. CONTACT hi@bitbeam.cn