Asymmetric Cryptographic Systems
Hewlett-Packard Company Virtual Private Networking Concepts Guide
2-9
Asymmetric Cryptographic Systems
Asymmetric Cryptographic Systems
Asymmetric Cryptographic Systems
Asymmetric Cryptographic Systems
Some algorithms do not use the same key to encrypt and decrypt.
These algorithms are referred to as asymmetric, are usually
complex, and often rely on the properties of very large prime
numbers. A simple asymmetric algorithm, similar to the
symmetric example, uses the same formula for encryption:
DW = shift-right ( AT , 3 )
In the symmetric example the encryption was "undone" using the
mathematical operation of "shift-left." If you change the
decryption operation to "shift-right," you need a different key to
arrive back at the clear text:
AT = shift-right ( DW , -3 )
Note that the key used to decrypt the cipher text in this case is
different from the key used to encrypt the clear text. The keys,
however, are related. The relationship between the keys in the
simple asymmetric algorithm can be expressed:
Ke = -1 * Kd
When asymmetric cryptography is used, the person doing the
encrypting does not need to know the same key as the person
doing the decrypting.
Asymmetric cryptography is often referred to as a public key
cryptography. The public and private keys used in asymmetric
cryptography are sometimes called key pairs, and are always
related through some mathematical operation.
Related
Related
Related
Related
Information
Information
Information
Information
Symmetric Cryptographic Systems (page 2-3)
Symmetric Vs. Asymmetric Cryptography (page 2-10)
Key Space and Brute Force Attacks (page 2-13)