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Cryptography - A Brief History
The
concept of securing messages through cryptography has a long history.
Indeed, Julius Caesar is credited with creating one of the earliest Cryptographic
systems to send military messages to his Generals.
(When Julius Caesar
sent
messages to his trusted Acquaintances, he didn't trust the messengers.
So he replaced every A by a D, every B by a E, and so on through the alphabet.
Only someone who knew the shift by 3 rule could Decipher his messages.)
Throughout history, however, there has been one central problem limiting
widespread
use of Cryptography. That problem is key management. In Cryptographic
systems,
the term key refers to a numerical value used by an Algorithm to alter
information,
making that information secure and visible only to individuals who have
the corresponding
key to recover the information. Consequently, the term key management
refers to the
Secure administration of keys to provide them to users where and when
they are required. Historically, Encryption systems used what is known
as "Symmetric Cryptography".
Symmetric Cryptography
uses the same key for both Encryption and Decryption.
Using Symmetric
Cryptography,
it is safe to send Encrypted messages without
fear of interception
(because an interceptor is unlikely to be able to decipher
the message)
however,
there always remains the difficult problem of how
to securely transfer
the key to therecipients of a message
so that they can Decrypt the message.
CRYPTOGRAPHY - A
BRIEF HISTORY-II
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