Jason Parms

Our bills – digitized. Our portfolios – digitized. Our tax returns – digitized. Our conversations – digitized.

Almost every single ounce of lives has become digitized. There is no escaping it. The Internet has engulfed our lives with its digital tentacles. And, it has made life easier too. There is fewer papers floating around our desks. But, with that convenience comes a ton of security issues too. Your online identity can be easily forged. Your website can be easily duplicated. Or the emails and the attachments that you send within it can be easily altered.

Digital signature and digital certificate products were introduced into the market to thwart such security concerns. They might seem like interchangeable terms that mean the same. But they are not.

A digital signature and a digital certificate are two different things. They perform different functions, one cannot replace the other one. You might need both a digital signature and a digital certificate in your daily life. So, it is good to know what they are and how they make a difference to your online security.

Digital Signature – An Immutable Virtual Signature

As the name indicates, a digital signature is a virtual signature. No, it is not your handwritten signature scanned and made a digital copy of. Instead, it is a digital attachment to a file that establishes the identity of the signer. The identity or the contents of the document to which it is attached cannot be altered. If at all an attempt is made to do so, it will invalidate the digital signature making the whole document redundant.

A digital signature helps in establishing the following in relation to a data shared across a digital medium:

  • Authenticity: ensure that the contents of the document to which it is attached is not tampered with by the recipient.
  • Integrity: Ensure that both the sender and the receiver receive the same document containing the same data with integrity.
  • Non-repudiation: Prevent the signer from denying or non-repudiation of signing the document at a later stage.

Digital Certificate – An endorsement of legitimacy

A digital certificate is a tiny-sized server file which is issued by a Certificate Authority (CA). The CA is usually a reputed security organization like an online security agency, a tech company, a government organization, etc. who run a background check of the certificate applicant before issuing them the certificate. The certificate establishes the genuineness and legitimacy of the information like the ownership of the website, the location, name of the business that owns the domain, etc.

Here is how a digital certificate makes a difference in our digital worlds:

  • It ensures that the flow of data between the sender and receiver is tamper-proof.
  • It prevents any unauthorized personnel from eavesdropping into the data exchange.
  • It scrambles the data so that only the recipient with the key to decrypt has access to the real data.
  • The recipient can check for legitimacy of the information by looking up the ownership of the sender.

Differences between a Digital Signature & A Digital Certificate

There are four major differences between a Digital signature and a digital certificate. We will dissect the differences in detail.

  Digital Signature Digital Certificate
What does it do? Verifies and establishes the identity/source of a document. Example: PDFs of contracts, employment offers, tenders or bids, quotations, tax filings etc. Establishes the credentials, legitimacy and in some cases, even the ownership of an online medium, like a website or an email.
How is it obtained? Individuals can obtain Digital Signature by applying for it any online security agency or issuing authority along with their personal identification documents. The digital signature is usually issued in the individual’s name and for specific purposes. There are several classes of Digital signature each denoting a specific purpose for which it can be used. Issued by a Certificate Authority who after conducting a background check of the applicant issues the certificate (in the form a server file).
What level of security does it provide? Ensures that nobody can hold the signer accountable or liable for documents no signed by him electronically. Ensures that the signer cannot non-repudiate the signing of the document later which protects the rights of the document’s recipient. Ensures that two parties who are exchanging information over the Internet are secured from any mishaps like cyber security attacks in the nature of Man-In-The-Middle attacks, eavesdropping, Cross-site scripting, etc. Provides the user a level of assurance that they are dealing with a reliable and genuine source as indicated by the website.
Techniques used for encryption 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. A digital certificate works on the principles of public key cryptography standards (PKCS). It creates certificate in the X.509 format.

Conclusion

A digital signature is largely used to sign digital documents that are shared across the Internet. They ensure the integrity and non-repudiation of the document. A digital certificate on the other hand is used to secure exchange of information across the Internet. They serve two different purposes, both of which are integral to online security.