Free strong encryption software for linux

Come And Go Encryption provides an encryption program based off one-time pads.
Cum And Go Encryption is a very basic program to encrypt or decrypt a program using a variant of the one-time pad. This allows for almost uncrackable encryption.
Why is it still crackable? The program uses one relatively small key to XOR the contents of another file, encrypting it.
A one-time pad uses a very large key (about the same size as the file/data to encrypt) and is completely random. Still, the encryption is good enough to mask the identity of a program or document, or stop someone from accessing that document or program.
The origins of this program were an effort to stop a specific kind of movie and image from being viewed normally.
Installing is a breeze: simply run the program. Put it anywhere you like, it wont matter as long as you put the full path to the program to encrypt/decrypt.
Run the program to see a basic description of its use.
This program works very well in windows but was designed for use in Linux/UNIX. The stdout option allows for decryption to standard output, allowing one to pipe the programs decrypted data to another program.
This could be used to view an encrypted movie without having to write the whole movie to disk; the only problem with this is that on some Operating Systems pipes are slow and inefficient, especially with a high-bitrate movie. Steps will be taken to speed this up in the future.
Enhancements:
- Fix password use so the password is not shown in "encrypted" files
- Use an actual encryption method, and not a cheesy XOR
- Adapt CAG to use modules such as SHA, Crypt, MD5, and others

StrongBad Emails is an extension which adds the words "Previous" and "Next" to the StrongBad Emails.

Tired of having to go back to the main email page to view the next Strong Bad email cartoon? Well wake up and smell the coffee with this extension.

Eureka Messenger 4 software delivers secure and private messaging and unlimited file transfers over the internet.

This application no longer requires the VB Runtimes, but this new version 4 is not compatible with the previous windows version.

Installation:

Actually there is no install for this application. You can run it right where you unzipped it, or copy the files unzipped wherever you want them.

If there is a firewall on either machine, some configuration may be required in order to make a connection.

The program has a Help file to guide you on how it works, although it is simple enough to run without much assistance.

You probably need to issue a chmod +x messenger before it can run. On some linux systems you may also need to issue a chmod +755 messenger.

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.

Eureka Encryption SDK Shared Library allows you to use Eureka Encryption in your own applications. Encrypt or decrypt strings or files.

Eureka Encryption shared Library installation instructions:

Start a terminal session and navigate to the folder where the files are located and enter the following commands:

chmod +x eursdk.so (this may be optional)

cp eursdk.so /usr/lib

ldconfig /usr/lib

The library is now ready for use. Load up the sdkhelp.htm file with any web browser for detailed information on its use.

Should anyone wish to translate the help files in other languages and send them to me, I would be happy to include them and repackage the tarball.

FlexiCrypt is a universal cryptography toolkit for managing certificates and symmetric keys. FlexiCrypt can perform many kinds of encryption, decryption, signing, and several related tasks.
Main features:
- key managing (asymmetric and symmetric)
- generate certificates
- symmetric encryption
- asymmetric encryption
- hybrid encryption
- decryption
- XML-signatures
- message digest computation
- secure file deletion (wipe files)
- performance comparison

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.

CryptoMX Tools is a set of encryption, steganography, cipher, hashing and conversion tools designed to work on any operating system with any Javascript-capable browser.
Enhancements:
- Added SHA-256 Algorithm.
- Used COPYING, README, AUTHORS, and ChangeLog Files.
- Removed a bit of useless code.
- Decreased Filesize.
- Misc. Fixes.