Certifying Authorities Rules, 2000

3. The manner in which information be authenticated by means of Digital Signature.-

A Digital Signature shall

(a) be created and verified by cryptography that concerns itself with transforming electronic record into seemingly unintelligible forms and back again

(b) use what is known as "Public Key Cryptography", which employs an algorithm using two different but mathematical related "keys" – one for creating a Digital Signature or transforming data into a seemingly unintelligible form, and another key for verifying a Digital Signature or returning the electronic record to original form, the process termed as hash function shall be used in both creating and verifying a Digital
Signature. 

Explanation: Computer equipment and software utilizing two such keys are often termed as

"asymmetric cryptography".