Terminology and encryption algorithms

Encryption algorithm (code) - a math function that encrypts and decrypts data. To encrypt data, one has to provide a key that is made of symbols.

Block codes - the most widespread algorithms, they encrypt data by blocks of certain sizes and transform that data with keys into blocks of the same size.

Blowfish - one of the most powerful block encryption algorithms, developed by cryptography guru Bruce Schneier. Block size is 64 bits, key size - up to 448 bits.

CAST - a rather dependable algorithm with key length up to 64 bits. Developed by C.M. Adams and S.E. Tavares, who offered it at AES competition.

DES - outdated encryption standard used in the USA. Due to security compromises (cracked by any modern computer within 2 days) it was replaced by AES. Developed by National Institute of Standards and Technology (NIST).

GOST - soviet algorithm created by KGB at the end of 1970s. Works with 64-bit blocks. Key length - up to 256 bits. Despite several security holes found, still considered to be rather dependable. Official encryption standard of the Russian Federation.

Rijndael - algorithm, developed by Joan Daemen and Vincent Rijmen. Meets AES standards (Advanced Encryption Standard). Uses blocks of different sizes (128, 192 and 256 bits) and equal-size keys.

Twofish - algorithm that replaced Blowfish, authored by Bruce Schneier as its predecessor. Considered to be hack-proof (no known incidents of code-cracking).

3DES - uses DES algorithm, by is applied three times with different keys, which increases dependability when compared to DES but does not change the situation radically (still vulnerable).

RC4 - a stream encryption algorithm used in many network security systems (for example SSL protocol used in Netscape and Windows NT password encryption). The major advantages of this code is very fast speed and adjustable key size. This algorithm was developed in RSA by Ronald Rivest. RC stands for "Ron's Code" or "Rivest Cipher". Used to be the intellectual property of RSA up to 1995.

Serpent - developed by Lars Ramkilde Knudsen, a famous cryptographer and cryptoanalyst, known for successful cryptoattacks of several popular codes, who worked and lectured in Norwegian, Swedish, and Belgian universities. Currently, Lars is a professor of math at Denmark's Technical University.

Tea - strong algorithm (Tiny Encryption Algorithm). Its most prominent feature is a very small size. Tea is very simple, does not use table values and is optimized for 32-bit processor architecture, which makes it possible to use it with ASSEMBLER, even when the code size is extremely small. The drawbacks include slow work and the need for "data scrambling" since no tables are used.

Dictionary attack - a method of cryptoattack that uses a regular dictionary that contains popular words. This attack method is worthless when "meaningless" passwords are used.

BruteForce - a method of cryptoattack used most often. It was coined "brute force" because an attacker tries to pick the key by randomly combining different symbols, numbers and letters (naturally, this is done by computer). To pick 128-bit key with BruteForce attack, it will take several years on average. The more characters used in the password and/or key the longer it will take to crack the code (up to hundreds of years).

See:

• Data backup
• File/Folder Encrypt/Decrypt
• File/Folder Erase