Basic idea of Cryptography is to convert original message to encrypted message. Converting can either make the encryption process hidden, so that an intruder remain unknow it Or, can use a known technique and use a hidden key. Some terminology such as Plaintext - original message ,Ciphertext - encrypted message ,Cipher - transforming algorithm for plaintext to ciphertext,Key - infomation used in cipher known …show more content…
It is known to all and the encryption key is secret. The same key is used by both the sender and the receiver. Traditional secret/single key cryptography uses one key where the sender should be able to communicate to the receiver the secret key by using a secure channel. A cryptanalyst who is able to obtain several pieces of ciphertext not be able to guess the key. (As the encryption algorithm is normally public knowledge). If this key is disclosed communications are compromised.
But public key cryptography apply two keys, a private and a public key. If parties are not equal then It is asymmetric. To encrypt message and verify signature, a public key that known to public can be used. To decrypt message, and sign signature ,a private key that known only to the recipient can be used. Public key cryptography introduced to address two issues: digital signature and key distribution. Key distribution implies how to secure communication without having to trust a KDC with your key. Digital signature implies how to verify a message comes intact from the …show more content…
Digital signing can be provided using cryptography through the Asymmetric algorithm, Hashing functions or mixture of this two. Mostly common hash algorithm used in industries are SHA1 and MD5. Operation involve in Digital Sign are message sign and verify. To sign a message sender computes digest of messages (hash) using agreed hash function, cryptographic signature is made by encrypting the digest using sender’s private key and digital signature sent along with message. Message itself may not be necessarily be private. To verify a message receiver recomputes digest of received message (hash) using agreed hash function, decrypt the digest using sender’s public key to extract sender’s original digest and finally verifies the recomputed and decrypted digest match. Signature decryption identifies sender and verifies integrity of the message. Cryptography is greatly applied for authentication through various kind of protocol in