Digital Certificate

• A digital certificate is used for authenticating a Web client or a web server.

• A digital certificate is issued by a reliable authority called the certification authority (CA)

• A CA provides a digital certificate to a requester only when it has throughly checked the identity of the requester.

• Eg. of CA's are: Verisign, Satyam Infoway, Cybertrest etc.

• The figure shows the layout of the certificate. It has the following information: Holders name. CA's name and signature, Public key of holder, validity, ID number.

• Working of Certificate:

1. If customer 'C" wants to send his credit details to shop 's', c will want to verifythe identity of s.

2. c will ask s for s's digital certificate.

3. s sends its digital certificate to c.

4. Now the certificate sent has the public key of S.

5. C uses this public key of S to encrypt his credit card details and sends the encrypted details to S.

6. S can decrypt the credit card details of C using its private key.

7. In this way only S will be able to decrypt the credit card details of C.