B2B Integration : A Practical Guide to Collaborative E-commerce

294 B2B Integration — A Practical Guide to Collaborative E-commerce
Secret
Secret
Message Encryption
with
Company A Private Key
Decryption
with
Private Key
Message
Company —J B
Figure 10.2. — Private key encryption
10.6.2. Private key encryption
Private key encryption, also called symmetrical encryption, was the
simplest way the encrypted messages were sent in the earlier times. It
used the same unique code called single key or private key for encrypting
as well as decrypting the messages.
Consider a scenario in which Company A wants to send Company B
a secret message (see Figure 10.2). If a single private key is used,
• Company A informs Company B about its private key.
• Company A encrypts the message with its private key and sends the
message across.
• Company B makes use of the private key (sent over earlier) to
decrypt the message.
This encryption method has several obvious limitations. Firstly,
there has to be some secure way by which Company A will initially
communicate the private key to Company B. If an outsider gets hold
of this private key, the entire communication will be compromised.
Secondly, Company A becomes completely vulnerable to Company B
and if Company B wishes it can use this private key to impersonate
Company A. Finally, this method is not suitable for multi-party communication—
for example a B2B exchange may be communicating
with hundreds of companies for which it will have to distribute the
private key to all the companies; and as the number of companies
increases, it can be compromised easily.
The most commonly used private key encryption algorithms are RC2
(40 bit encryption) and RC4 (128 bit encryption). Both of these were
invented by RSA Data Security. 56-bit DES is another algorithm that is
primarily used for unclassified government documents.