The electronic age has brought forth many
technological advances. With these

advances came the need for security and
tighter control on how we send

information electronically over the Internet
or through a network. Date

encryption is, in its simplest terms, the
translation of data into a secret

code. In order to read an encrypted file,
the receiver of the file must obtain a

secret key that will enable him to
decrypt the file. A deeper look into

cryptography, cryptanalysis, and the
Data Encryption Standard (DES) will provide

a better understanding of date
encryption. Cryptographic Methods There are two

standard methods of
cryptography, asymmetric encryption and symmetric

encryption. Data that is in
its original form (unscrambled) is called plaintext.

Once the data is
scrambled and in its encrypted form it is called ciphertext.

The
ciphertext, which should be unintelligible to anyone not holding
the

encryption key, is what is stored in the database or transmitted down
the

communication line. Asymmetric encryption (also know as public key
encryption)

uses two separate keys, a public key and a private key. The
private key is

available only to the individual receiving the encrypted
message. The public key

is available to anyone who wishes to send data or
communicate to the holder of

the private key. Asymmetric encryption is
considered very safe but is

susceptible to private key theft or breaking of
the private key (this is

virtually impossible and would constitute trying
billions of possible key

combinations) (4). Types of public key algorithms
include Riverst-Shamir-Adelman

(RSA), Diffie-Hellman, Digital Signature
Standard (DSS), EIGamal, and LUC (5).

Symmetric encryption uses only one
key (a secret key) to encrypt and decrypt the

message. No public exchange of
the key is required. This method is vulnerable if

the key is stolen or if the
ciphertext is broken (4). Types of symmetric

algorithms include DES,
Blowfish, International Data Encryption Algorithm

(IDEA), RC4, SAFER, and
Enigma (5). Cryptanalysis Cryptanalysis is the art of

breaking cryptography.
Methods of cryptanalysis include: „h Ciphertext-only

attack ¡V the attacker
works from ciphertext only. The attacker does not know

anything about the
message and is merely guessing about the plaintext (6). „h

Know-plaintext
attack ¡V the attacker know the plaintext. Knowing this

information, the
attacker can attempt to decrypt the ciphertext (6). „h Chosen

plaintext
attack ¡V the attacker can have a message encrypted with the unknown

key. The
attacker must then determine the key used for encryption (6).
„h

Man-in-the-middle attack ¡V the attacker intercepts the key that is
being

exchanged between parties (6). Data Encryption Standard (DES) In 1977
the

National Institute of Standards and Technology (NIST) and IBM
developed the Data

Encryption Standard, or DES, to provide a means by
which data could be

scrambled, sent electronically to a destination, and then
unscrambled by the

receiver. DES was developed to protect data in the federal
computer systems

against passive and active attacks (3). Every five years the
NIST reviews the

DES and determines whether the cryptographic algorithm
should be revised, is

acceptable, or completely withdrawn. DES uses a very
complex algorithm, or key,

that has been deemed unbreakable by the U.S.
government. There are

72,000,000,000,000,000 (72 quadrillion) or more
possible encryption keys that

can be used. It applies a 56-bit key to each
64-bit block of data. This process

involves 16 rounds of operations that mix
the data and key together using

operations of permutation and substitution.
The end result is a completely

scrambled data and key so that every bit of
the ciphertext depends on every bit

of the data plus every bit of the key (a
56-bit quantity for DES) (2).

Conclusion Sending secure electronic
information is vital for businesses today.

Although the electronic age
has made it easier for companies to send and receive

information, it has also
increased the need for security. Data encryption in

itself will not assure
any business of sending secure information, but

understanding it will surely
benefit the company. Businesses who understand

cryptography, cryptanalysis,
and Data Encryption Standard are on their way to

understanding data
encryption.

Bibliography

1. Bay Networks, Inc. (1997). Configuring
Software Encryption. www.baynetworks.com

2. Biasci, L. (1999).
Cryptology. www.whatis.com.

3. Frazier, R.E., (1999). Data Encryption
Techniques. www.softstrategies.com.

4. Litterio, F., (1999). Cryptology:
The Study of Encryption. www.world.std.com.

5. SSH Communications
Security, (1999). Cryptographic Algorithms. www.ipsec.com.

6. SSH
Communications Security, (1999). Introduction to
Cryptography.

www.ipsec.com.