There are a large number of encryption algorithms. The most widely methods include :

*DES *- Data Encryption Standard was
developed more than 15 years ago, and is one of the
most respected algorithms. It has withstood most attempts
to crack it, and currently exists in a number of versions.

*CRYPT(3) *- A version of DES for
UNIX systems.

*RC2 and RC4 *- This
algorithm has a variable key size. It was developed by Ron Rivest
for RSA Data Security, Inc. RC is short for “Ron’s Code”. The
algorithm itself has never been made public.

*IDEA *- This encryption algorithm
works on 64 bit blocks containing data previously
divided into four sub-blocks. Encryption then takes place,
and the blocks are combined in different ways.

*RSA *- Ron Rivest, Adi Shamir and
Leonard Adleman introduced this algorithm in 1978, and
it remains one of the strongest encryption algorithms
in use. RSA uses shared and private keys for encryption/decryption.
However, RSA is a slow algorithm - at it fastest
it is 100 times slower than DES in software.

*SNEFRU *-
This is a one-way hash algorithm designed by Ralp Merkle. Thehash function
converts incoming data to 128 or 256 bit values.

*MD2 *- A one-way hash function
designed by Ron Rivest.The function produces a 128 bit hash value from incoming
data.

*MD4 *- A one-way hash function
designed by Ron Rivest. MD meansMessage Digest, and creates a 128 bit hash value
from incomingdata.

*MD5 *- MD5 is a further development
of MD4, and also creates a 128 bithash.

*SHA *- Secure Hash Algorithm,
developed by the National Institute ofStandards and Technology with the National
Security Agency. SHAis very similar to MD4.

*RIPE-MD *- A version of MD4. It was
developed by the EU's RAC project.

*HAVAL *- A one-way has function
with variable length.

*SKIPJACK *- A top secret algorithm
for Clipper and Capstone (encryption chips).

The code and algorithms are known only by highly cleared USGovernment and contractor personnel.

*DFFIE-HELLMAN *-

The first public key algorithm created.The algorithm can be used for distributing keys.

*XOR *- There are a large number of
XOR encryption algorithms. They areamong the simplest, and a very fast.

*BLOWFISH - *A type of XOR
encryption, but much stronger.