.C9R File Extension

Cryptomator Encrypted Data

Developer Skymatic
4.3  |  4 Votes

What is a C9R file?

A C9R file is a file that has been encrypted by Skymatic Cryptomator, an open-source data encryption tool. It contains a file or directory that a user has placed in their Cryptomator vault. C9R files can be decrypted by unlocking the vault in which they are stored.

More Information

C9R file shown in Apple Finder
C9R file shown in Apple Finder

Cryptomator is a file encryption app that allows users to store files in a virtual drive and then lock that drive. Locking the drive encrypts the stored files, using AES-256 encryption. Often, users place their Cryptomator drives in cloud storage services, so they can access the drives (and the files they contain) from multiple devices.

Files encrypted by Cryptomator use the .c9r extension, to denote they've been encrypted. These files also have encrypted filenames produced using AES-SIV encryption. Thus, a file previously named Example.rtf may have a filename like eHwTYFBFYdmnj2cVBF-hgHXjoH7sVD4ZUwpz.c9r after being encrypted by Cryptomator.

How to open a C9R file

You can decrypt a C9R file, and access the encrypted data it contains, with Cryptomator (multiplatform). To do so, you must unlock the file vault in which the C9R file is stored. To add a vault to Cryptomator, select Add Vault → Open Existing Vault. Then, follow the prompts to add your vault to Cryptomator and unlock its contents (you will likely have to enter the password used to lock the vault).

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Programs that open C9R files

Verified by FileInfo.com

The FileInfo.com team has independently researched the Cryptomator Encrypted Data file format and Mac, Windows, Linux, Android, and iOS apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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