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Know The Difference Between Digital Signature and Digital Certificate

Signing vs Certificates – What You Should Know

There is quite a bit of confusion out there about what is a digital signature and what is a digital certificate. After all, they are both security measures and they sound the same, so it is understandable that people might think they are synonymous.

However, there are some vital differences between digital signatures and digital certificates in terms of their implementation and purpose. In this article, we’ll explain what a digital signature is and how it works with digital certificates.


What is a Digital Signature and How it Works

A Digital Signature is a tool used to verify that a received document or transaction has been generated and sent by the sender without the interference of any third-parties. It is a guarantor of authenticity, assuring the receiver that the document they have received has not been tampered with.

How is a Digital Signature Performed?

The Digital Signature Standard (DSS) is used for performing digital signatures. The DSS standard was issued by the National Institute of Standards and Technology (NIST) as the Federal Information Processing Standard (FIPS) PUB 186 in 1991.

There are two primary techniques used to perform a digital signature:

  • DSS uses the SHA-1 algorithm in order to compute the message digest against the original, utilizing the message digest in the generation of the digital signature. This is done by using the Digital Signature Algorithm (DSA), which is, in turn, based on asymmetric key cryptography. This process does not provide encryption of messages.
  • Digital Signature can also be performed using the RSA algorithm. This method is used when the message needs to be encrypted as well.

Reasons to use a Digital Signature

  • Authenticity: Digital Signatures can assure the receiver that the message really has been sent by the correct sender. This assurance is extremely important in financial transactions.
  • Integrity: Messages sent by someone can often be tampered with by malicious third-parties to alter their original meaning. Upon using a digital signature, any alterations to the message renders the signature invalid. This gives assurance to the receiver that the message has not been altered.
  • Accountability: Once a digital signature has been used to transmit a message or document, the sender cannot claim that they didn’t send it. As such, digital signatures guarantee non-repudiation of origin.

What is a Digital Certificate and How it Works

Digital Certificates are essentially digital identification cards. They are issued by specific government bodies or certificate authorities after carefully verifying the individual’s identity and making sure that they meet all requirements for the certificate. Digital Certificates are essentially used to verify the owner’s identity when it is presented to others.

When a document is signed with a digital certificate, the relying party can be guaranteed of their authenticity because the Certificate Authority has done its job in verifying the individual’s identity.

Reasons to use a Digital Certificate

  • It holds personal information by which the owner’s identity can be verified.
  • The issuing authority can also be contacted.
  • Digital certificates are difficult to tamper with or duplicate.
  • If the identification is misused, the issuing authority can revoke it.
  • Revocation can be easily checked by contacting the issuing authority.

Digital Certificate vs. Digital Signature

Digital Signature Digital Certificate
Verifies the identity of the individual sending a document. Helps establish the legitimacy or ownership of an online platform such as an email or a website.
Can be obtained via an online security agency or issuing authority by presenting the relevant identification documents. Can be obtained by contacting the Certificate Authority. They conduct a background check before issuing the certificate.
Ensures that the signer cannot be held accountable for documents either tampered by third-parties or forged by them. It also protects the rights of the document’s receiver by negating non-repudiation. It protects people holding online transactions from cyber attacks, eavesdropping, cross-site scripting, etc.
Created with Digital Signature Standard (DSS) using SHA-1 or SHA-2 algorithms. Certificates are created in the X.509 format.
Note: Digital signature, Digital Certificate, and Digital Signature Certificate or electronic signature certificate are three different things.

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