The Advantages Of Adding A PKI Certificate Digital Signature

There are many different industries, individuals and groups that have a need for the ability to provide signed documents that are transmitted electronically. These are typically called digital signatures and they provide a type of fingerprint or a unique identifier that binds a specific document to a specific sender through the use of Public Key Infrastructure technology.

This is, in some ways, very similar to the meaning of SSL, although the digital signature is even more specific and legally accepted. In fact, SSL uses Public Key Infrastructure and the use of the pair of keys to encrypt and decrypt data that is being sent between a client and server or between two servers.

With the PKI certificate digital signature, the same type of public and private key structure is used, but forms a different part of the secure transmission of email and attached files.

The Basics of the PKI Certificate Digital Signature

It is important to keep in mind that the digital signature is unique and it is only associated with one user. This is done through those keys, which are actually long strings of random numbers that are mathematically related but do not match each other. In other words, the public and private key are not identical nor do they have areas in the string that mimic or copy the other key.

Once a user has a private key through a certificate provided by a Certificate Authority, that private key is bound to the owner and to the specific device where the request was generated.

This private key is used to electronically or digitally sign the document. This is done through both an encryption as well as a hash algorithm. To see how it is accomplished a specific example is always helpful.

If you don't have a PKI certificate on your computer or device you could create a legal document, let's say a contract, and send it to the person you were entering into the contract with. Sending it in plain text without encryption means that it could be intercepted by someone else, a third party, and the terms of the contract could be altered.

The individual receiving the contract would not be aware it had been altered and may just assume it is the original. This would create problems as you would each have a different contract with no way to know if it is was accurate or even sent by the person you thought it was from.

With PKI certificate digital signature this problem ceases to exist. When you create the contract and are ready to email it to the other party to the contract, you simply press the button to add a digital signature. This activates what is known as a hash algorithm that converts the contact into a string of numbers. This hash is then encrypted by the private key and sent.

The hash message and the public key arrive at the receiver's inbox. His or her email client recognizes there is a digital signature and uses the public key to decrypt the message to a corresponding hash matching the one sent. When these two match, the receiver will know that the sender is authentic and the file has not been tampered with or changed after it was signed.

Finally, for the receiver, this also ensures that the sender cannot repudiate sending the document at a later date. This is because he or she had to not only be using the device with the certificate but they had to be able to access the secure account using a unique password and username to access the private key to create the signature.

International Recognition

There are other methods used in to create security when transmitting information online. However, with the use of a PKI certificate digital signature, you will be implementing and using technology that is considered to be international. This technology is used in business, finance, government and in legal firms to quickly, securely and practically transfer information that is in a format the can be used in court to provide authenticity of documents.

For more information on how PKI certificate technology and protocols can be used to improve your email security and business document handling options, see our team at Comodo. For information on either corporate PKI certificates or personal certs, which are offered at no cost, see our team at You can also talk to us in person by phone at +1 888 266 6361 if you want to discuss your options.

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