PKI Digital Signature

Jake Ludin Education

PKI Digital Signature

Cryptography has different applications in the field of cybersecurity. From its origins, cryptography was applied to data protection to prevent unauthorized third parties from reading the information. Only those who have the key would be able to decipher the message.

In addition to encryption, cryptography (particularly asymmetric cryptography) can be used to verify the identity of a user and guarantee the integrity of the data. This is possible through the Digital Signature.

It is important to clarify the difference between an electronic signature and Digital Signature. The electronic signature can be any type of file, image, logo, or digitized handwritten signature that serves to identify a user but does not use any type of cryptography or sophisticated algorithm for its generation.

The Digital Signature is the result of the execution of a public key mathematical algorithm where the author uses his private key to sign the document and anyone can verify the authenticity of the document using the owner’s public key. In practice, the digital signature is part of the Public Key Infrastructure (PKI).

This important element of information security has varied uses and is applied every day in the activities we carry out online. It enables individuals and organizations to ensure the secure transfer of information, as well as to provide authenticity of data within an organization.

How a PKI Digital Signature Works

PKI digital signature is integrated in an encrypted way by complementary information that is sent along with the signed message. The algorithms that are used for the generation and verification of the message are the following:

  • Generation of random numbers
  • Generation of cryptographic keys using an asymmetric encryption algorithm
  • Cryptographic hash function
  • Digital signature algorithm
  • Digital signature verification algorithm.

In the process of generating a digital signature, the private key of the issuer of the message is used. During the verification process, the public key of the issuer is used.

For the generation of the digital signature, the hash function of the message to be sent is calculated. Remember that a cryptographic hash function allows inputs of varying data lengths to be transformed into a fixed-length string, called a hash value. The most important property of hash functions is that very small changes to the input values produce a completely different value as the output, thus making it very difficult to find collisions.

Returning to the digital signature, the hash of the message that is to be authenticated with the electronic signature is one of the values used to form the signature. In summary, the procedure for signature generation is as follows:

  1. A random number is generated
  2. The random element of the signature is calculated from that random number
  3. The hash value of the document to be signed is calculated
  4. Using the issuer’s private key, the random element, document’s hash value, and the electronic signature is generated.

The process for generating a PKI digital signature

On the other hand, it is equally important that the receiver can verify the electronic signature to authenticate the veracity of the authorship of the message. For this, the electronic signature verification procedure is carried out as follows:

  1. The issuer’s public key is obtained
  2. From the hash value of the document, the signature verification algorithm is executed using the issuer’s public key and the electronic signature itself
  3. The result of the algorithm must be yes or no based on whether the verification succeeds or fails

The process for verifying the validity of the digital signature

Every digital signature generally includes the following information:

  • Signature Date
  • End of validity date of the key belonging to the issuer
  • Information about the entity of the digital signature
  • Identifier of the signer (name of the public key)
  • Owner of the digital signature

The main strength of the digital signature is the impossibility of falsifying the issuer’s electronic signature without possessing the private key. An attacker who does not possess the private key will not be able to form a signed message or send it on behalf of the legitimate user.

Digital Signatures in Use

One of the most pervasive threats organizations face daily are attacks perpetrated through email messages, especially phishing attacks. Deceiving a network user through email is not particularly difficult. There are several effective methods used to accomplish this, such as imitating a company executive or engaging a user through fear or reward.

By using S/MIME certificates, an email message is accompanied with a digital signature to confirm the validity of a message. If an email is sent and the digital signature is not recognized, the recipient automatically knows not to trust the message. Additionally, a digital signature will identify the sender of a message and provide accountability within an organization.

Digital signatures can also be used in a wide variety of transmissions. It can be used to secure web transactions, such as a credit card transaction. Sending PDFs and Word documents can be done securely to ensure no other eyes will view the content within a message. And sensitive data transfers within an organization, or between multiple organizations, can be completed with full confidence of security.

 PKI Deployment with SecureW2

Deploying and maintaining a PKI is often the only barrier to entry for deploying certificates on a network and taking advantage of the security provided by PKI digital signatures. Installing and maintaining an on-site PKI is an expensive endeavor and often requires a team of trained technicians to manage.

SecureW2’s turnkey PKI is entirely cloud-based and easily integrates with any network infrastructure. It can be set up and configured in a manner of hours and be ready to distribute certificates. All the tools required to integrate certificate-based security and implement public key cryptography are made available. And the JoinNow onboarding solution makes it easy for users to self-configure their devices for certificates.

Ensuring the messages and data you receive come from a trusted source is key to maintaining network integrity. Too often are organizations taken advantage of by bad actors and coerced into giving up valuable data and monetary resources. Navigate to SecureW2’s pricing page to see if our PKI solutions could protect your organization from messaging manipulation.

Learn About This Author

Jake Ludin

Jake is an experienced Marketing professional who studied at University of Wisconsin – La Crosse. Besides the Wisconsin staples of eating cheese and wearing t-shirts in winter, he is often quoting from obscure 70s movies and longboarding along Lake Michigan.