written 5.8 years ago by | • modified 5.8 years ago |
Subject: Mobile Computing
Difficulty: Medium
Marks: 8 Marks
written 5.8 years ago by | • modified 5.8 years ago |
Subject: Mobile Computing
Difficulty: Medium
Marks: 8 Marks
written 5.8 years ago by | • modified 5.7 years ago |
Public key Cryptography: In this cryptography two different keys are used for encryption and decryption. Thos is also called as Asymmetric key cryptography. It is based on mathematical functions rather than permutation & substitution. The encryption key and decryption key form a key pair. One of the key from the key pair is made public and the other is kept private or secret. There are six main components
Plaintext: Human readable message or data given to public key algorithm as input for encryption.
Ciphertext:
This is the scrambled data produced as output of the format of data produced as output of the encryption algorithm. This is unique data and depends only on the unique key used for encryption.
Encryption Algorithm: It does computation and various transformations on the input plain text. The output of the transformation is too garbled to be decipherable for an intruder.
Decryption Algorithm: This algorithm does the reverse function of the encryption algorithm. This function accepts the cipher text as input and does some transformation on the data so that the original data is recovered.
Public Key: This is one of the keys from the key pair. This key can be used either for encryption or decryption.
Private key: This is the other key from the key pair. This key is called the private key, because this is kept secret. This can be used either for encryption or decryption.
Diffie Hellman Algorithm:
Consider Alice and Bob want to exchange the key