Cryptography is a very vast topic which contains many techniques to make the data secure. One such Cryptography technique is the public key Cryptography. In the public key Crypto Systems there are two keys, one is the Public key and other is the private key. The public key is made available to the outside world and is in confidential where as the private key is kept secret and is available only to a particular user. Here the public key is kept different from the private key. The public key is used for encryption whereas private key is used for decryption of the message.
A public key Crypto system can be compared to an ATM system where every user has his card and pin number which serves as private key and is kept immune from the outside world. The most common public key algorithm is the RSA algorithm which is named after its inventors Rivest, Shamir and Adleman. The public and the private keys here comprise of a pair of numbers. The encrypted text is calculated by applying some logarithmic routines to the public key and the original data. The original data is derived back by applying some logarithmic calculations to the private key and the encrypted data. This method serves quite well, as it is hard to crack due to the logarithmic calculations.
Besides RSA there are some other public key Crypto systems as well like Elgamal. The algorithm that follows Elgamal crypto system is the Elgamal signature algorithm. This algorithm is also based upon logarithmic calculations. It is pretty similar to the Diffie-Hellman method. The DSA (Digital Signature algorithm) also derives some of its features from this algorithm. This algorithm has similar results as that of RSA algorithm but its major disadvantage is that its speed is very slow.
LUC is another public key Crypto system which is based upon RSA, Diffie-hellman and Elgamal system. The encrypted message is made by the iterating the recurrences rather than logarithmic calculations as we use in the above public key algorithms. There are other algorithms as well which are based upon the algebric theory of coding like McEliece. The major advantages of the public key Crypto systems is that the number of keys used here are fairly small in comparison to the other Crypto systems and also it removes restrictions of a shared symmetric key between two entities. One disadvantage is that the complexity of the keys is very high.
by Camila 1 year ago
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