A digital certificate serves as a computer user’s credentials that let another party verify his/her identity to facilitate a secure online transaction. In essence, the certificate acts as proof of someone’s identity. For enterprises, the certificates serve as a numerical value or a public key cryptographic key that can be used to encrypt data to enable transactions over the Web via a secure connection without fear of compromise.

You can think of the certificate as a driver’s license or any proof of identification to validate your identity.

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Read More about a Digital Certificate

Digital certificates are critical to security. Find out why here.

What Kind of Security Do Digital Certificates Offer?

Since the certificates act as a verification step for sending mostly confidential data, there is a need to protect their integrity at all times. The question is: What benefits do the certificates offer users? Here are some of them.

1. Data Confidentiality

Users can rely on the certificates to check if the individual or organization they are communicating with is indeed who it claims to be. Without the public key, the other party cannot access the document or message a sender sends using his/her certificate. That assures the sender that no confidential data would leak or get lost or stolen.

2. Data Integrity

The certificates ensure that the information sent is free of deliberate changes or tampering during transmission to the intended recipient. That way, everything agreed upon, for instance, in a signed contract cannot be changed once signed.

3. Access Management

The use of the certificates ensures that only the parties involved in a transaction would have access to documents and other files.

4. Transaction Receipts

The beauty of using such a certificate lies in nonrepudiation. It ensures that both the sender and the receiver cannot deny sending or receiving messages related to the exchange.

What Is the Difference between a Digital Certificate and a Digital Signature?

Both digital certificates and digital signatures rely on public key cryptography, which offers both authentication and encryption. However, digital signatures are often obtained using algorithms for data signing. The resulting information confirms that a public key holder signed a document. Generating a digital signature requires using a one-way cryptographic hash, which randomizes data bits to create a value that can only be read by someone with the right key. If the signature’s hash remains unchanged from when its owner used it, it serves as a go signal for the recipient to treat the signed document as legal and binding.

Digital certificates, on the other hand, require two verified digital signatures (the sender’s and the recipient’s) before documents or files that use them can be considered authentic. That said, digital signatures and digital certificates work hand in hand.

What Are the Types of Digital Certificates?

Three types of digital certificates exist:

  1. Transport Layer Security (TLS)/Secure Sockets Layer (SSL) certificate
  2. Code signing certificate
  3. Client certificate.
Types of Digital Certificates

TLS/SSL Certificate

A TLS/SSL certificate is stored on a server and ensures communication with clients remains private and encrypted. It authenticates encrypted messages sent to and received from clients. All HyperText Transfer Protocol Secure (HTTPS) websites have a TLS/SSL certificate. It comes in three forms—domain-validated, organization-validated, and extended validation.

A domain-validated certificate is acceptable for any website, is cheap to obtain, and can be issued in a matter of minutes. An organization-validated certificate, meanwhile, provides light business authentication. It is ideal for companies that sell products online. Finally, an extended validation certificate offers full business authentication. It is a must for large enterprises or any business that deals with highly sensitive information. Financial industry players should have this certificate to offer the highest level of authentication, security, and trust.

Code Signing Certificate

A code signing certificate confirms the authenticity of software or files downloaded via the Internet. It signifies that the application’s developer or publisher confirms its genuineness. Any software available on third-party sites should have this to prove the files have not been tampered with.

Client Certificate

A client certificate is a digital ID that identifies an individual user or a machine to another user or machine. Emails typically have this certificate to signify that the sender signed the communication digitally and that his/her signature has been verified by the recipient. Such a certificate can also help users access protected databases.

What Information Does a Digital Certificate Contain?

The certificate contains a lot of information, including data about its owner and issuing certificate authority (CA). Here is a detailed breakdown of that data.

  • Distinguished name (DN) of the owner that identifies the fully qualified name instead of just the common name (CN) of the owner, the owner’s organization, and other distinguishing information
  • Owner’s public key
  • Date the certificate was issued
  • Date the certificate will expire
  • DN of the issuing CA
  • Digital signature of the issuing CA created using the message-digest function based on all the previously listed fields

What Are the Uses of Digital Certificates?

The certificates are mainly used to secure online transactions. Some of the typical applications of this public key cryptography method are listed below.

SSL

SSL uses digital certificates for server authentication, key exchange, and client authentication, which are processes critical in determining whether a message sender is who he/she claims to be. This protocol is commonly used in web servers to secure connections between browsers.

Email Security

Most email systems use the Privacy Enhanced Mail (PEM) or Secure/Multipurpose Internet Mail Extensions (S/MIME), which are file formats used for storing and sending cryptographic keys. To make the exchange of messages as secure as possible, they use the certificates to verify digital signatures and key exchange to encrypt and decrypt messages.

VPN

Also known as “secure tunnels,” virtual private networks (VPNs) use the certificates to ensure that communication between secure networks over an unsecured network remains protected.  

SET

Secure Electronic Transaction (SET) is a protocol commonly applied in credit card transactions done over an unsecured network. The certificates secure communications for merchants, banks, and cardholders, making all transactions indisputable or unforgeable.

How Do You Get a Digital Certificate?

You can obtain a digital certificate by applying to a CA, which is responsible for generating codes or keys on your behalf. You can then receive your pair of public and private keys and a certificate containing the public key along with a valid CA signature. Note, however, that there may be instances when an applicant may need to personally meet with a CA representative to validate his/her identity.

It is your responsibility to keep your private key secure at all times. Compromised or lost private keys must always be communicated with the issuing CA.

If you don’t want to purchase a digital certificate, you can still digitally sign your documents by creating a self-signed certificate. However, other people who will receive your digitally signed document can’t check its authenticity.

Who Can Issue a Digital Certificate?

A CA, which more organizations deem trustworthy. Or if you are just starting a business and have yet to have enough resources to secure a CA’s services, you can issue one.

Note that as of 2025, securing a digital certificate can cost between US$26 a month for a basic certificate and US$108 a month for a secure site pro certificate.

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The Internet is not inherently secure. And so, over time, cybercriminals continuously devised ways to exploit the technology’s users for their gain. Digital certificates came to the fore as a means for organizations to safely communicate and engage in online transactions.

Key Takeaways

  • Digital certificates act as credentials to verify someone’s identity online.
  • They use public key cryptography to encrypt data and ensure secure connections.
  • They come in three types—TLS/SSL, code signing, and client certificate.
  • They contain a lot of information, including data about their owners and issuing CAs.
  • Their benefits include data confidentiality, integrity, access management, and nonrepudiation.
  • They require the verified digital signatures of the sender and the recipient. 
  • They are typically used in SSL, email security, VPNs, and SET.
  • They can be obtained from a CA.
  • You can also create and use a self-signed SSL certificate, but others cannot verify its authenticity.

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