Description  Background of the invention
1. Field of the Invention
The present invention relates to data security.
2. Description of the Related Art
Many different types of data security measures are known. Presently,
most widespread data security measures are based on publickey
encryption. Publickey encryption is described, for example, in U.S.
Pat. No. 4,218,582, incorporated herein by reference. Other patents
relating to publickey encryption include U.S. Pat. Nos. 4,200,770;
4,405,829; 4,424,414 and 4,995,082, all of which are incorporated
herein by reference.
One of the reasons for the relative prominence of publickey
cryptography is that it solves the problem of key distribution in an
elegant fashion.
Prior to publickey cryptography, symmetrickey cryptography required
use of the identical key to decrypt the file as was used to encrypt
the file. Hence, the key had to be communicated in secrecy between
users. In publickey encryption, the encryption and the decryption
keys are separate, with the encryption key being publicly known and
the decryption key being kept secret. Publickey encryption may also
be used for authentication.
Despite the important advantage of not requiring secure key
distribution, publickey cryptography also suffers from various
disadvantages. Administration is typically required to ensure that
unique publickeys are assigned to each user. A person's publickey
must be listed in a directory, and must be found in the directory
prior to encrypting a message. The computational burden of publickey
cryptography is significant both in generating random prime numbers
for use as keys and in encryption and decryption processing itself.
Furthermore, despite the computational complexity, publickey
encryption using medium size keys has been shown to be insecure given
the tremendous network computing resources that may be brought to bear
on breaking the encryption.
What is needed, then, is a data security mechanism that surpasses in
security present publickey cryptography methods and that minimizes
the computational burden involved.
Next: Summary
of the invention
References
Cited / Other References  Claims  Background of the invention
 Summary of the invention  Brief of the drawing
 Detailed description of the preferred embodiments
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