4.0 Requirement of public key cryptography
The requirement of public key cryptography is listed below:
>> It is computationally easy for party B to generate a pair of keys that is :
(Public key & Private key)
(Public key & Private key)
>> It is computationally easy for a sender A must know the public key and
encrypt the message M, to generate the cipher text.
encrypt the message M, to generate the cipher text.
C = Ekub(M)
>> It is computationally easy for receiver B to decrypt the cipher text using
it’s PRIVATE KEY.
M=Dkrb (C) = Dkrb[Ekub(M)]
>> It is computationally infeasible for an opponent , knowing the public key KUb,
to determine the private key KRb
>> It is computationally infeasible for an opponent , knowing the public key KUb,
and cipher text to recover the original message M.
>> The encryption and decryption function can be applied in either order.
M = Ekub [Dkrb(M)] = Dkub[Ekrb(M)]
