A digital signature is an electronic signature that can be used to authenticate the identity of the sender.
Digital signature cannot be forged and it asserts that a named person wrote or otherwise agreed to the document to which the signature is attached.
The recipient of a digitally signed message can verify that the message originated from the person whose signature is attached to the document and that the message has not been altered either intentionally or accidentally since it was signed.
In other words, digital signatures enable the "authentication" and "non-repudiation" of digital messages, assuring the recipient of a digital message of both the identity of the sender and the integrity of the message.
The Office of Controller of Certifying Authorities (CCA), issues such certificates only to certifying authorities and the latter issues Digital Signature Certificates to the end user.
Certification Authority (CA) are appointed by the office of the Controller of Certifying Authorities (CCA) . There are 7 such agencies authorized by the CCA to issue DSCs.