The cryptography with an open key is a system of enciphering of data with use of the opened and closed keys. The open key is transferred on the unprotected channel.
The open key is used for
- digital signature checks,
- encryptions of data.
The confidential key is used for
- digital signature generation,
- interpretations of data.
Data are ciphered, according to an open key. At the same time he almost doesn't allow to execute the return process – to decipher data. It can be compared to so-called unilateral function when on known x there is a value f (x). However to receive the unknown x on known f (x) it is almost impossible. In other words, the open key allows to cipher data, but doesn't allow to decipher them. Doesn't allow to decipher them for reasonable time more precisely, using available computing resources.
To learn x (basic data) on known f (x) () it is required to the ciphered data a special confidential key, having applied which to f (x) it is possible to receive x. Therefore interception of data doesn't allow to decipher them, knowing only open key.
For modern systems of cryptography with an open key on condition of a right choice of keys calculation of the confidential key corresponding public, is considered impossible (at an existing level of development of mathematics).
The cryptography with an open key is very often used in various network protocols. To organize the protected communication channel, it is enough to two parties to exchange open keys. Can be so that the open key is transferred by only one party.