Free cryptography 101 software for linux

CryptoServer is OpenSource Server-side cryptography tool and run as daemon.

It is already tested in very busy environment and can support over one million transaction an hour.

CryptoServer accept the GPL License and can use it for any purpose as is.

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

The CryptoBox is a Debian/Linux based live-cd. CryptoBox CD boots up, starting a secure fileserver.
Even non-technical users are able to store their data on its encrypted harddisk. There is no special knowledge about cryptography or servers required at all.
The CryptoBox is fully controllable via your web browser.
Version 0.2 is fully usable and runs stable. From now on were just adding features and translations (atm english, german, slovenian).
Enhancements:
- Support for more than one hard disk was added.
- Manual partitioning is allowed.
- LUKS is used for hard disk encryption.
- Plaintext partitions are supported.
- The time and date can be changed.
- Flexible feature management was implemented to enable and disable specific plugins.
- Prepared RAID partitions are used.

trfcrypt is an add-on package to the tcl-extension trf. It provides the encryption functionality which was removed from the base package to allow its inclusion on the Tcl/Tk CDROM without violating US export control laws on cryptography.
The C API is layered on top of the trf C API and provides a set of commands for the management, implementation and usage of blockciphers and stream.
Although it is possible to implement ciphers using only the trf C API the code in this package makes it much easier, as general things like the handling of blockcipher modes are done here, thus obviating the need to reimplement them every time. A new cipher just has to provide some information about itself (key sizes) and functions to:
- generate the internal keyschedule from the specified key
- encrypt/decrypt a character or a block of data

LibTomCrypt is a comprehensive, modular, and portable cryptographic toolkit that provides developers with a vast array of well known published block ciphers, one-way hash functions, chaining modes, pseudo- random number generators, public key cryptography, and a plethora of other routines. It has been designed from the ground up to be very simple to use. It has a modular and standard API that allows new ciphers, hashes, and PRNGs to be added or removed without change to the overall end application. It features functions for easy handling and a complete user manual which has many source snippet examples.
LibTomCrypt is a fairly comprehensive, modular and portable cryptographic toolkit that provides developers with a vast array of well known published block ciphers, one-way hash functions, chaining modes, pseudo-random number generators, public key cryptography and a plethora of other routines.
LibTomCrypt has been designed from the ground up to be very simple to use. It has a modular and standard API that allows new ciphers, hashes and PRNGs to be added or removed without change to the overall end application. It features easy to use functions and a complete user manual which has many source snippet examples.
LibTomCrypt is free for all purposes under the public domain. This includes commercial use, redistribution and even branching.
Main features:
- Public domain and open source.
- Written entirely in portable ISO C source (except for things like RNGs for natural reasons)
- Builds out of the box on virtually every box. All that is required is GCC for the source to build.
- Includes a 90+ page user manual in PDF format (with working examples in it)
- Block Ciphers
- Ciphers come with an ECB encrypt/decrypt, setkey and self-test interfaces.
- All ciphers have the same prototype which facilitates using multiple ciphers at runtime.
- Some of the ciphers are flexible in terms of code size and memory usage.
- Ciphers Supported.
- Blowfish
- XTEA
- RC5
- RC6
- SAFER+
- Rijndael (aka AES)
- Twofish
- SAFER (K64, SK64, K128, SK128)
- RC2
- DES, 3DES
- CAST5
- Noekeon
- Skipjack
- Anubis (with optional tweak as proposed by the developers)
- Khazad
- Changing Modes
- Modes come with a start, encrypt/decrypt and set/get IV interfaces.
- Mode supported.
- ECB
- CBC
- OFB
- CFB
- CTR
- One-Way Hash Functions
- Hashes come with init, process, done and self-test interfaces.
- All hashes use the same prototypes for the interfaces.
- Hashes supported.
- MD2
- MD4
- MD5
- SHA-1
- SHA-224/256/384/512
- TIGER-192
- RIPE-MD 128/160
- WHIRLPOOL
- Message Authentication
- FIPS-198 HMAC (supports all hashes)
- FIPS pending OMAC1 (supports all ciphers)
- PMAC Authentication
- Message Encrypt+Authenticate Modes
- EAX Mode
- OCB Mode
- Pseudo-Random Number Generators
- Yarrow (based algorithm)
- RC4
- Support for /dev/random, /dev/urandom and the Win32 CSP RNG
- Fortuna
- SOBER-128
- Public Key Algorithms
- RSA (using PKCS #1 v2.1 and PKCS #1 v1.5)
- DH (using ElGamal signatures and simple DH encryption)
- ECC (over Z/pZ, ElGamal Signatures, simple DH style encryption)
- DSA (Users make their own groups)
- Other standards
- PKCS #1 (both v1.5 and v2.0 padding)
- PKCS #5
- ASN.1 DER for INTEGER types.
Enhancements:
- The ECC code was fixed, cleaned, and improved.
- GCM was fixed.
- UTF8 support was added to the ASN1 code.
- The documentation was improved.
- The published version of the manual is included.

TaoCrypt project is a portable, fast, cryptographic library for most needs.
Main features:
- one way hash functions: SHA-1, MD2, MD4, MD5, RIPEMD-160;
- message authentication codes: HMAC;
- block ciphers: DES, Triple-DES, AES, Blowfish, Twofish;
- stream ciphers: ARC4;
- public key cryptography: RSA, DSA, Diffie-Hellman;
- password based key derivation: PBKDF2 from PKCS #5;
- a pseudo random number generator and large integer support.
There is also support for Base 16/64 encoding/decoding, DER encoding/decoding, and X.509 processing.
To build:
./configure
make
To test the build, from the ./test directory run ./test
Enhancements:
- This release includes bugfixes, portability enhancements, and some optimizations.

CPPSERV is an application server that provides Servlet-like API to C++ programmers.

CPPSERV project consists of stand-alone daemon, listening on TCP socket for requests from web server, and web server module.

Currently only apache-2.0.x is supported, but writing modules for other web servers should be fairly easy.

Coinflip provides a cryptographically secure server/client program and protocol for choosing random bits.

Coinflip is a client/server based program that can generate random bits for 2 people over the internet. The 2 people dont have to trust each other in order to convince each other that the bit is truly a random bit.

Its called coinflip, of course, because flipping a coin in the real world is the equivalent of generating a random bit on a computer. (Its either heads or tails. Its either a 1 or a 0.)

Coinflip uses a slightly modified version of the "Coin Flipping Using One-Way
Functions" protocol outlined in Bruce Schneiers Applied Cryptography 2nd
edition.

This attack would work everytime Alice acted as the server in a coinflip procedure, providing Bob never realized that Alice was sending him the same y value every time. Or she could us it to trick multiple Bobs.

While it is supposed to be computationally infeasible to compute collisions in one-way hash functions, recent papers suggest that if you have enough money and time, collisions can be precalculated. P. van Oorschot and M. Wiener in their paper, "Parallel collision search with application to hash functions and discreet logarithms", estimate that for $10 million (in 1994 US dollars), a collision could be found for MD5 in 24 days on average. (Thanks for the info, defrost).

The solution is actually quite simple: Have both parties choose part of the random data, and use whatever size random number you like. Since Bob is expecting to see x contain his random data, Alices collision attack is nullified, and since Alice gets to put in her own data, she can make Bobs array attack infeasible.