Crypter
🔓✨🔒 An innovative, convenient and secure encryption app
Install / Use
/learn @HR/CrypterREADME
Encrypt unlimited bits. Remember only a bit.
Crypter is a cross-platform crypto app that makes encryption and decryption convenient while still upholding strong security. It tackles one of the weakest links in most security systems today - weak passwords. It simplifies secure password generation and management and requires you to only remember one bit - your MasterPass.
Crypter v4.0 is a crypto app that can decrypt and encrypt any arbitrary data this includes files and folders. This version has been released and fully tested for macOS (OSX), Linux (for all distros via AppImage) and Windows (32 & 64 bit). All core modules (modules that provide the core functionality) are fully tested.
Crypter v5.0 will save your MasterPass in your OS's Keychain so you won't have to enter it every time you open the app. To help speed up the development please send a PR for what's left do https://github.com/HR/Crypter/milestone/4
Please open an issue if you have any suggestions and add improvements via PRs!
Also checkout Ciphora (https://github.com/HR/ciphora) a decentralized end-to-end encrypted messaging app.
Link to this README: https://git.io/Crypter.info
Contents
<!-- TOC depthFrom:2 depthTo:6 withLinks:1 updateOnSave:1 orderedList:0 -->- Installation
- Screens
- Crypto
- CRYPTO file
- Security
- FAQs
- How do I encrypt a file or folder?
- How do I decrypt a CRYPTO file?
- How do I encrypt multiple files?
- Why am I getting the "Corrupted Crypter file or trying to decrypt on a different machine." error?
- Why can't I decrypt a CRYPTO file on a different machine with the same MasterPass?
- Why can't I decrypt a CRYPTO file with the same MasterPass?
- Where are my encrypted/decrypted files/folders placed?
- How can I access Crypter's preferences?
- How can I reset my MasterPass?
- What is a valid MasterPass?
- What are MasterPass credentials?
- How can I export my MasterPass credentials?
- How can I import my MasterPass credentials?
- Development
- License
<!-- /TOC -->
Installation
All prebuilt binaries for all major platforms are available under releases.
Crypter is also on Homebrew Cask for macOS. So to install it, simply run the following command in the Terminal:
$ brew install --cask crypter@4.0.0
Screens
<p align="center"> <img src="/.github/Welcome_screen.png?raw=true" alt="Welcome screen" width="100%"> <img src="/.github/Crypter_main_screen.png?raw=true" alt="Crypter screen" width="40%"> <img src="/.github/MasterPass_screen.png?raw=true" alt="MasterPass screen" width="40%"> <img src="/.github/Settings_screen.png?raw=true" alt="Settings screen" width="85%"> </p> <br/>Crypto
One key to derive them all!
Crypter derives a MasterPassKey from the MasterPass obtained at setup by using the PBKDF2 key derivation algorithm (see below for the specification). It then uses PBKDF2 to derive a number of encryption keys from the MasterPassKey that can be used for the encryption of files. This method allows for the generation of very secure encryption keys for data encryption. Moreover, by publicly storing the credentials used to derive the MasterPassKey and the salts used to derive the encryption keys, you are able to produce the encryption keys at will and without needing to store them securely. Your MasterPass is the only thing that you need to remember.
Crypter never directly encrypts anything with your MasterPass. Instead, it derives a MasterPassKey from it, which it then uses to derive the encryption key used to encrypt your file. Every time a file is decrypted, the encryption key is re-derived from the MasterPassKey. Every time you set the MasterPass through the setup or reset it through Verify MasterPass, the MasterPassKey is derived from the MasterPass using a newly generated set of (random) credentials. These credentials are used to re-derive the MasterPassKey every time that Crypter is executed (i.e. the app is launched).
Authentication with the AES-256-GCM symmetric block cipher is used by default. This ensures that data integrity is verified on decryption and allows the app to detect tampering or data corruption.
The following are the crypto defaults and can be found under app/config.js:
// Crypto defaults
{
ITERATIONS: 50000, // file encryption key derivation iterations
KEYLENGTH: 32, // encryption key length
IVLENGTH: 12, // initialisation vector length
ALGORITHM: 'aes-256-gcm', // encryption algorithm
DIGEST: 'sha256', // digest function
HASH_ALG: 'sha256', // hashing function
MPK_ITERATIONS: 100000 // MasterPassKey derivation iterations
}
Encryption process
When encrypting a file, Crypter first creates a temporary hidden directory, namely '.crypting'. It then encrypts the user-selected file with the crypto defaults and flushes the encrypted data to a file in the directory, namely 'data'. If it is a directory then it is compressed first (tar). It also writes the public credentials to a file within the same directory, namely 'creds'. Finally, Crypter compresses the directory to a tar archive with the name of the user-selected file and the '.crypto' extension appended to it.
Decryption process
The decryption process is essentially the inverse of the encryption process. During decryption, Crypter creates a temporary hidden directory named '.decrypting'. It then reads the credentials from the creds file and decrypts the data file into the original file or directory (after decompressing it) with its original name and extension, as deduced from the CRYPTO file name (e.g. the extension for "file.txt.crypto" would be ".txt").
Public credentials
Certain credentials are required to decrypt the encrypted data. These are needed to reconstruct the particular encryption key and to verify data integrity. These can be stored publicly without compromising security since it is fairly impossible (by current standards) to reconstruct the encryption key without the MasterPass and its credentials. These credentials are stored in the creds file of the CRYPTO file archive (as delineated above) in the following format:
v1
Crypter#iv#authTag#salt#dir
v2
Uses JSON
{
"type": "CRYPTO",
"iv": "...",
"authTag": "...",
"salt": "...",
"isDir": true || false
}
The dir part is only included for directories
<br/>
CRYPTO file
Format
A CRYPTO file is the product of the Crypter encryption process. This file
stores both the encrypted version of the user file and the public credentials
needed to encrypt and decrypt it. It has a .crypto file extension, which
is appended to the full file name (including the extension) of
