A digital signature acts as a traditional handwritten signature that can be used to authenticate the identity of a user as well as the document content. It stores information about the signer along with the date, time, and state of the document when it was signed.
When you are signing a document with a digital signature, this signature represents the Digital ID of the person signing the document at a given time.
The digital ID is the identity of a person/organization, which contains your name, e-mail address, a serial number, an expiration date, and the name of the company. A digital ID consists of two keys; one is a public key (certificate) that is used to encrypt or lock data, and the other is a private key that is used to decrypt or unlock data that is encrypted.
You can also distribute the certificate that contains the public key and other identifying information to those people who need to use it to verify your identity, validate your signature, or encrypt a document for you. The content of the document that was encrypted using your certificate can be unlocked only by your private key. For that sole reason, you should store your digital ID in a safe place.
You can not only obtain a digital ID from a trusted third-party provider called a Certificate Authority (CA), but you can also create a new certificate by specifying necessary information, using one of the key algorithms RSA 1024 or RSA 2048.