Free come and go encryption software for linux

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.

EasyCrypt is a small Python program that encrypts or dercypts files using AES encryption standard.

The program is still in early development. It can be used to easily encrypt your files on the go with pretty good security. It works or all systems that support Python. (Windows, Unix, MacOS, ...).

The program uses PyCrypto (link here) library to encrypt/decrypt the file. (Pyhton doesnt have yet an official implementation of the AES algorythm). Since the sourceforge doesnt have any downloadable package, I included in the cvs tree the version of the library used in the program.

Usage (example):

> pycrypt --encrypt TestFile.jpg TestFile.jpg_enc mypassword
(An encrypted file has been created)
> pycrypt --decrypt TestFile.jpg_enc DecryptedFile.jpg mypassword
(The original file is recovered)

twocrypt provides a crypto tool with a deniable encryption option.
twocrypt (2c) is a tool for the ultra-paranoid, providing a traditional crypto, but also an option of deniable (subpoena-proof) encryption. It encrypts one or two files at once.
Each file can be recovered with its respective passphrase, but the presence of more than one file cannot be demonstrated, and the presence of this option alone should not be a credible argument for data hiding.
2c2 is a simple symmetric file encryption utility. It comes with an
interesting optional feature - it is capable to embed an additional file
within an encrypted data. This is done in a way that cannot be detected
without knowing the passphrase protecting the "hidden" file, even if the
password for the primary file is disclosed. The design is such that the
fact of using this method alone does not constitute a credible evidence of
data hiding (IANALBMSUTDO). This kind of encryption is also called
"subpoena-proof" or "deniable".
There is some previous work in this area. There are two popular approaches,
one is to throw away the encryption key, but store some information that
can be used to recover the key with a considerable computation effort
(several years or so). The concept seems to be risky for obvious reasons,
and is also impractical if the data has to remain accessible before the
projected cracking date.
The other approach is to have a number of containers protected with a number of passwords, of which some but not all might be encrypted data (rubberhose does that). I think its needlessly complex, and usually applied to a storage such as a disk drive.
As such, 2c would be the first tool to implement this functionality in a
reasonable and practical fasion, at least I think so.
Enhancements:
- It was possible to tell a two-file result from a single-file output,
_statistically_. This does not mean the question can be answered for a
particular archive, but single-file archives had a tendency to result
in a slightly larger file, and if you have a number of 2c-protected
files for which the primary password has been obtained, it can be
told how you use 2c. The reason for that was slightly broken compressed
pad length logic.
Severity: medium
- As a cryptographic safeguard, the random pad stream now consists of
a random, compressed file of a random length, followed by true garbage.
This is to mimick second file scenario more closely, so that if the
encryption proves weaker than originally thought, and some statistical
properties of a stream can be deduced, theres no exposure. Version
1 always used a full-length compressed pad, which was silly in that
its not that common to store perfectly-fit secondary files.
Severity: hypotetical issue
- In v1, random chunk would seldom get compressed, because the compression
algorithm resorted to storing uncompressed data if compression would
result in output bigger than input. This is not a flaw per se, but
defeats a minor safeguard intended to mimick a file that would often
be compressible. Now, encryption of all blocks is forced, even though
it might be less efficient.
Severity: hypotetical issue
- Input blocks are now split randomly to avoid placing compression
headers and other known structures at constant locations. This is just
another arbitrary safeguard for the algorithm.
Severity: hypotetical issue
- per Jamess suggestion, I added a counter to the PRNG generator
internal state. This prevents a hypotetical (although *extremely*
unlikely) generator stall scenario. This spectacularly breaks v1
compatibility, blame James ;-)
Severity: low

Gnome Memory Blocks project is a concentration game for GNOME.

This is GNOMEs version of the `memory blocks game originaly come from Semantec game pack for Win-3.11

smsjoker-script is a script to send SMS over the SMS-Script-Gateway of http://www.smsjoker.de/
I use it to send SMS out of kaddressbook in KDE 3.5.x with:
smsjoker-script "%N" "%F"
An other interesting usage is to send an text (like "Merry Christmas and a happy new Year") to every number in an textfile.
Usage: /Path/to/the/script/smsjoker [Options] [Destination] [Text]
If you enter [Destination] you must also enter [Text]
[Destination] can be an number or the path to an textfile with numbers on each line
[Text] can be the SMS-Text or the path to an textfile with the SMS-text in it
If you dont give Destination and Text you come to the interactive-mode
Possible Options:
-t [eigen|anonym] eigen shows your own Cellphone-Number as sender not an standard-one
-d Go to Debug-Mode
-p Enforce Popups
Enhancements:
- Important Update: The IP of the smsjokers http-interface will change. You should update to 2.4 now.

Checkpoint Commander is a cross-platform file management, viewing, and archiving / security tool.
Checkpoint Commander project includes optional archive encryption using AES (AES-CBC-HMAC-SHA1).