What is the REM file format?
A .rem file is a proprietary encrypted file created by BlackBerry (formerly Research In Motion) when a device stores data on an encrypted microSD media card. The .rem format wraps different types of data - images, documents, video, and more - with .rem appended as a compound extension to the original filename. For example, photo.jpg becomes photo.jpg.rem. This compound naming preserves the original file type in the leading extension, even though the encrypted binary payload has no readable file signature.
BlackBerry devices encrypt these files using AES-256 with a master key stored on the microSD card. The encrypted files can be decrypted only on the original BlackBerry phone by turning off the media-card encryption option. After decryption, the restored files can be transferred to a computer using legacy BlackBerry Desktop Software.
Common underlying types include JPEG images, PDF documents, PNG images, and MP4 video. No modern desktop software can open .rem files natively; forensic recovery is possible through tools such as Elcomsoft Phone Breaker.
Security & safety
RISK: MEDIUMThe .rem file itself is just encrypted data and harmless to store. The real risk is in 'recovery': searches for 'rem file decrypter' or 'open rem online' lead to dubious tools, fake decryptors, and adware/PUP downloads that cannot actually decrypt a device-bound .rem. Do not upload personal files to unknown online 'decrypt' services. The only legitimate routes are on-device decryption (turn off card encryption on the original BlackBerry) or, in the password-mode case, reputable forensic software you pay for. If the phone is gone and Device Key mode was used, accept that the data is effectively unrecoverable rather than paying a scam.
Format details
in a nutshell- BBEdit / generic 'remarks' or LaTeX REVTeX backup files - Some text tools and TeX workflows use .rem as plain-text reminder/remark files - unrelated to BlackBerry encryption.
- Remind calendar/reminder script files - The Unix 'remind' program uses .rem text files for appointment reminders - plain text, not encrypted.
Programs that open REM files
Windows3 apps
BlackBerry Desktop Software (legacy)
Free On an older Windows PC with the original phone connected, transfer media - it decrypts .rem during copy. Note: this software is discontinued.
Original BlackBerry device (decrypt on phone)
Built-in Insert the card in the phone that encrypted it; Options > Media Card > Encryption > None to restore originals, then copy off.
Elcomsoft Phone Breaker (forensic, last resort)
Paid Only if the card used Device Password mode and you know the password - derives the key to decrypt. Fails for Device Key mode. 
macOS1 app
Original BlackBerry device (decrypt on phone)
Built-in Decrypt on the phone (Options > Media Card > Encryption > None); macOS has no .rem decryptor. Legacy Mac Desktop Software is discontinued. Technical details
deep spec| Developer | BlackBerry (formerly Research In Motion) |
| Format type | Proprietary encrypted binary container |
| MIME type | application/octet-stream |
| Encryption | AES-256 symmetric encryption |
| Key storage | Master key stored on the originating microSD media card |
| Filename convention | Compound extension - `.rem` appended to the complete original filename (e.g., `photo.jpg.rem`) |
| Original type identification | Leading extension in the compound name reveals the wrapped format (e.g., `.jpg` in `photo.jpg.rem`) |
| File signature | None - encrypted payload produces no recognizable magic bytes; bytes appear random |
| Decryption requirement | Must be performed on the originating BlackBerry device that created the file |
| Decryption method | Disabling media-card encryption in device settings strips `.rem` and restores original files |
| Key portability | Non-portable - decryption key is bound to the specific microSD card and originating device |
| Desktop software | BlackBerry Desktop Software (Windows, legacy) for file transfer after on-device decryption |
| Forensic tool | Elcomsoft Phone Breaker (Windows) for key extraction and decryption without the original device |
| Underlying file types | Any format stored on the card - commonly `.jpg`, `.pdf`, `.png`, `.mp4`, `.doc` |
| Released | c. 2008 (BlackBerry OS media-card encryption) |
| Specification | fileinfo.com |
REM conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about REM files.
