Free file encryption software for linux

Fire Encrypter is an Firefox extension which gives you encryption/decryption and hashing functionality right from your Firefox browser, mostly useful for developers or for education & fun.
The new FireEncrypter is ready! (v-3.0, this version contains the following ciphers:
- AES (Rijndael 128Bit)
- Affine
- Caesar
- XOR
- OTP (One Time Pad)
- Vigenere
- Rail Fence
- Morse Encoder
- MD2 Hashing
- MD5 Hashing
- SHA1 Hashing
- SHA256 Hashing
- SHA384 Hashing
- SHA512 Hashing
- Secure password generator.

Gaim-Encryption uses NSS to provide transparent RSA encryption as a Gaim plugin.
Main features:
- Automatically creates a public/private key pair for you upon loading the plugin
- Automatically transmits your public key to other users.
- Supports 512 - 4096 bit keys.
- Saves keys of known users, and warns you if their public key has changed.
- Embeds all encryption and keys inside HTML, so if the other user doesnt have the plugin, they will get a little message telling them about the plugin, and wont get a screen full of garbage.
- Stores keys in human readable files in your .gaim directory, in case you ever need to copy/edit them by hand. Which you really shouldnt have to do.
- Automatically recognizes if you are chatting with someone who has the plugin- see the Preferences dialog.
- Available for the Windows version of Gaim.
- Modular and extensible. If you want to define a different type of encryption, you can use this plugin as a wrapper to take care of transporting the encrypted binary over the IM pipe.

Eureka Encryption Global Edition contains file encryption, multiple encryption, merge encryption, multiple file encryption, embedded applications (Crypt Words, Steganographer, Interface) and other tools such as a file shredder and scrambler.

Eureka Encryption Global Edition is available for Windows, Mac and Linux. Other applications are available from the website.

TinyCrypt is a NEW encryption algorithm, not written by an expert, nor significantly peer-reviewed. For protecting critical data, please consider alternatives until TinyCrypt is proven.
That said, if youre just having fun, or have data that is more easily stolen while youre away from your computer having lunch, feel free to continue...
The point of TinyCrypt is to both compress and encrypt your file VERY quickly... faster than your computer can read and write the file. Its compression is based on the super-fast LZO compression library.
TinyCrypt is meant to be simple, fast, and secure. By secure, we mean secure enough for typical commercial use, not TOP SECRET documents. The core encryption file is only 59 lines of code. The core function within this file is 14 lines, including comment header. Feel free to read through it to get familiar with it. Its very simple, and very fast. The SimpleCrypt utility (included with TinyCrypt) uses just this encryption code to protect data.
TinyCrypt attempts to insure high security, using the ultra-fast SimpleCrypt hashing algorithm plus extra steps: First, it compresses the data using the fast LZO compression library. Then, it diffuses the data and obfuscates it using a 256-byte random key and the SimpleCrypt algorithm.
The random key is then prepended to the obfuscated data for later use in decrypting. Finally the obfuscated data is re-encrypted using the users key and the SimpleCrypt algorithm. This approach deflects know-plaintext attacks, reduces the encrypted file size, and is still blazing fast.
Enhancements:
- Added -c flag

Encrypt This! is a Firefox extension that allows public key like encryption as well as passphrase methods.

Visit the extensions homepage to set up public and private keys or just go ahead with a passphrase of your own creation.

Using this extension you can select text and have it encrypted in one click. This will allow you to send emails more securely by ensuring that nobody other than your intended recipient can read the decrypted text.

Blowcrypt is a file encryption utility based around the blowfish algorithm. It has a Tk frontend but can also be used from the command line.

The key length is currently set to 448 bits. (the maximum that is permitted by the blowfish algorithm.) The system has been designed to be modular. The base modules are the blowcrypt and RSA Data Security, Inc. MD5 Message Digest Algorithm (from here on after referred to as md5) c++ and c programs. These do the actual encryption, key hashing and authentication.

On top of these, there are the encrypt and decrypt perl scripts which manipulate the base programs. These perl scripts can be called from any script or cronjob making system administration of encryption of large files systems easier. Finally, there is a tk program, called tkblow. This is a GUI frontend to the perl scripts and enables multiple selection of files for encryption and decryption.

The system has been successfully tested on linux (2.2-20-12 Redhat 6.1)
The system requirements are as follows:-
Linux os
perl 5
Tk 8
c and c++ compiler (i used the standard one which comes with the RedHat distro (gnu gcc and g++)

This software is released under GNU GPL.

Crypt is a small C program that utilizes the crypt(3) function to include DES password checking/encryption in shell scripts.

Usage:

./crypt < salt > < string >

Bcrypt project is a lightweight blowfish file encryption utility which aims for cross-platform portability of not only the actual code, but the encrypted files as well.
In addition to providing 448-bit encryption, Bcrypt overwrites input files with random garbage.
Installation:
If youre so inclined, edit config.h and change the defaults to whatever you think is appropriate for your needs. If you choose not to have bcrypt remove input files after processing, or set SECUREDELETE to 0, you are likely to have data on your hard drive that can be recovered even after deletion. All of these options can be set on the command line as well.
When youre satisfied with the default settings, simply type:
make
then su and type:
make install
It would be wise to test the installation on a few unimportant files before encrypting anything you value, removing the only copy and overwriting it 127 times with garbage.
Usage:
bcrypt [-orc][-sN] file ...
Encrypted files will be saved with an extension of .bfe. Any files ending in .bfe will be assumed to be encrypted with bcrypt and will attempt to decrypt them. Any other input files will be encrypted. If more than one type of file is given, bcrypt will process all files which are the same as the first filetype given.
By default, bcrypt will compress input files before encryption, remove input files after they are processed (assuming they are processed successfully) and overwrite input files with random data to prevent data recovery.
Passphrases may be between 8 and 56 characters. Regardless of the passphrase size, the key is hashed internally to 448 bits - the largest keysize supported by the blowfish algorithm. However, it is still wise to use a strong passphrase.
Options:
-o print output to standard out. Implies -r.
-c DO NOT compress files before encryption.
-r DO NOT remove input files after processing
-sN How many times to overwrite input files with random data before processing. The default number of overwrites is 3. Use -s0 to disable this feature. No effect if -r is supplied.
Enhancements:
- 1.1 fixes a few minor bugs and adds support for many new operating systems.
- 1.1 is immensely faster than 1.0.
- Additionally, it uses about 50% as much memory with compression turned off, or 66% with compression on.
Notes: If you previously used 1.0 on an unsupported platform, you may not be able to decrypt any encrypted files you have. Alpha systems are known to have this problem. 32 bit systems should not have this problem. 64 bit systems probably do. If your system exhibits this problem, you should decrypt your files with 1.0 and reencrypt them with 1.1.