What is the difference between synchronous and asynchronous cryptography?

Answer 1

in synchronous communication data will be transmitted with clock and in asynchronous only start and stop bit is required for transmission of data

but speed of the data transmission in synchronous is very high data rate

and in asynchronous speed is slow due to the start and stop bit

Answer 2

I believe you are asking about "symmetric vs asymmetric" cryptography. In a symmetric cryptographic cipher both parties must use the same key for encryption and decryption. This means that the encryption key must be shared between the parties before any decryption of the message can take place. This transfer of the shared key opens the door for potential detection of the key. These are commonly referred to as "shared secret systems" or "private key systems". In an asymmetric cipher, the encryption key and the decryption keys are separate. In an asymmetric system, each person has two keys. One key, the public key, is shared publicly. The second key, the private key, should never be shared with anyone. When you send a message using asymmetric cryptography, you encrypt the message using the recipients public key. The recipient then decrypts the message using his private key. That is why the system is called asymmetric. Because asymmetric ciphers tend to be significantly more computationally intensive, they are usually used in combination with symmetric ciphers to implement effect public key cryptography. The asymmetric cipher is used to encrypt a session key and the encrypted session key is then used to encrypt the actual message. This gives the key-exchange benefits of asymmetric ciphers with the speed of symmetric ciphers. Examples of symmetric ciphers are AES and DES. Examples of asymmetric cipers are RSA and Diffie Hellman.

Answer 3

I think you may be confusing synchronous/asynchronous communication with symmetric/asymmetric key encryption. Not being certain which you are inquiring about, I'll try to explain each term: Synchronous communication is used for example, in computer transmission of data, whereby a timing mechanism is used so that each device has a pre-defined period of time to deliver its message. Asynchronous communication occurs with your standard phone for example. Anyone can talk whenever they want and the message is transmitted. Symmetric key encryption describes the use of a single, secret key that is shared between the sender and the recipient. The sender encodes the message using the secret, and the recipient is the only other person who can decode it because he's the only other who knows the secret. Asymmetric key encryption involves the use of mathematically related key pairs - one key is used to encrypt the message, and the other must be used to decrypt it. The concept for asymmetric key exchanges is a bit complicated, if you'd like further info, I suggest doing a search on Public Key Cryptography.

Answer 4

The major differences between synchronous encryption and asynchronous encryption is in terms of security and communication. For asynchronous encryption, there is no need for secure exchange one or maybe more secret keys between the concerned parties during the initial stage. The reverse is true of synchronous encryption. There are similar keys or keys with simple transformation with each other that are known to the concerned parties, more like a private link of information.