Networks Security Interview Question:

Explain How do we use RSA for both authentication and secrecy?

Submitted by: Administrator

RSA is based upon public key/private key concept. For authentication one can encrypt the hash (MD5/SHA) of the data with his private key. This is known as digital signature. And secrecy is achieved by encrypting the data with the public key of the target user. Generally we dont use RSA for encryption because of key size (1024 bits). Rather a symmetric session key (128/256 bit) is established between communicating parties and is used for encryption.

RSA -- Authentication can be achieved by using nonce value (prime number).
Eg: A wanna communicate with B
The val An1 is encrypted with private key of A and then with pub key of B. so B can decrypt it and then B should send back the An1 to A stating it none other than B

Secrecy is also maintained because they use their own private keys for decryption
Submitted by: Administrator