Digital signature:

1. A digital signature is a mechanism that is used to verify that a particular digital document, message or transaction is authentic.

2. Digital signatures are used to verify the trustworthiness of the data being sent

3. Digital signature is to ensure that a data remain secure from the point it was issued and it was not modified by a third party.

4. It provides authentication, non-repudiation and integrity 

5. A digital signature is created using a Digital Signature Standard (DSS). It uses a SHA- 1 or SHA-2 algorithm for encrypting and decrypting the message.

6. The document is encrypted at the sending end and decrypted at the receiving end using asymmetric keys.

Digital certificate:

1. A digital certificate is a computer file which officially approves the relation between the holder of the certificate and a particular public key.

2. Digital certificates are used to verify the trustworthiness of the sender.

3. Digital certificate binds a digital signature to an entity

4. It provides authentication and security.

5. A digital certificate works on the principles , of public key cryptography standards (PKCS). It creates certificate in the X.509 or PGP format.

6. A digital certificate consist of certificate’s owner name and public key, expiration date, a Certificate Authority ‘s name , a Certificate Authority’s digital signature.