You’ve just hit gold if you’re looking for an answer to the question “what is an X.509 certificate?” An X.509 certificate is a form of digital certificate that can be used in a variety of ways on the internet. In reality, you’re using one right now as you browse our site.
In a nutshell, X.509 certificates aid in the protection of organisations and individuals from those attempting to impersonate or spy on them. They do this by using asymmetric keys and third-party validation, which we’ll go through in greater detail later.
So, let’s get this party started. We’ll go through the following key points about X.509 and X.509 certificates in this article:
What Is an X.509 Certificate?
Websites, users, companies, and other organisations can use an X.509 certificate to prove their identities on the internet. To put it another way, they use an X.509 certificate to prove their identity, much like a passport. An X.509 certificate, to put it another way, is a form of digital certificate that provides third-party authentication to websites, users, companies, and other organisations all over the internet. Third-party authentication is the word for this.
Couldn’t anyone just steal your X.509 certificate and use it as a fake ID if you have one for your business? Heh, not so easy. That’s because of something called public key infrastructure, or PKI for short.
The international X.509 public key infrastructure (PKI) specifications include X.509 certificates. These guidelines were first published in 1988, and they have been revised every few years since then. The X.509 PKI specifications were last revised in October of this year. Since they’re developed and maintained according to these formatting requirements, X.509 certificates are also known as public key certificates (or PKI certificates). Since an X.509 certificate binds knowledge about you (the organisation) to a cryptographic public key and makes that key accessible to third parties, others can’t just steal and use your certificate as their own. A public key is one half of an asymmetric key pair, which also requires a private key.
A Quick Look at the X.509 Certificate Format
The identifying details about your company, your public key, and the digital signature of the body that issued your certificate are all included in an X.509 certificate. More precisely, each certificate’s X.509 certificate format includes the following information:
- Your distinguished name.
- Your public key.
- The distinguished name of the issuing body (usually a public certificate authority, which we’ll discuss shortly, but self-signed certificates are also available).
- The digital signature of the issuing body (which is signed by their private key).
- Dates of certificate issuance and expiration.
Who Issues X.509 Certificates?
The organisations responsible for issuing X.509 digital certificates are certificate authorities (CAs), which were initially known as certification authorities. They do this to ensure that each certificate they issue complies with relevant authentication requirements and validates correctly.
When people speak about certificate authorities, they usually mean public certificate authorities. Private CAs, on the other hand, will issue and self-sign certificates for use within their own companies and intranets. (For public-facing applications, self-signed certificates can never be used.)
Sectigo is an example of a widely recognised certificate authority. Despite the fact that there are hundreds of CAs around the world, only a few dozen or so issue the vast majority of certificates used globally.
The Roles That CAs Play in X.509 Certificates
So, what exactly are CAs responsible for? The X.509 specifications, which were released in 2016, state:
Okay, that was a bit of a mouthful. Let’s take a look at it…
CAs Validate Organizational Identities to Ensure They’re Legitimate
Before issuing a public key certificate to someone, a certificate authority verifies that the requestor (your company) is legitimate. If you want to obtain an X.509 certificate for your company website, for example, there are three options:
- Domain validation (DV) entails the CA using automation to check that the domain in question is managed by the entity in question. This usually entails sending an email to a domain’s registered email address, or sending an email containing files that must be uploaded to a domain’s unique folder.
- Organizational validation (OV) — The CA performs simple business validation in this mid-level validation phase. This proves not only that you own or manage the domain, but also that your business is legitimate. This helps to create confidence by demonstrating that CA has confirmed the company’s identity and, as a result, you’re trustworthy.
- Extended validation (EV) is the most comprehensive of the three forms of validation. It necessitates several verification tests using the certificate requestor’s records as well as other third-party sources.
CAs Bind Unmodifiable Public Keys to Organizational Identities
The CA now attaches the checked identity to the organization’s public keys after validating the organisation. Consider it identical to the official seal on your passport. This aids in establishing the authenticity and veracity of your identity.
So, what is it about this public key that makes it so special? When stable cryptographic algorithms and sufficient entropy (randomness) are used to generate keys, they are basically “unforgeable.” This implies that they can’t be changed or updated in any way without being detected.
What Are the 4 Types of X.509 Certificates?
It could surprise you to learn that there are multiple types of X 509 certificates. There are a lot of them, and they’re all used for different things. To help you understand the differences, we’ll go over each X.509 certificate example in detail, explaining what they are and why they’re useful.
TLS Certificates (SSL Certificates)
Start with the most popular and widely used X.509 certificate. A TLS certificate, also known as a website security certificate, enables your browser to connect to a website’s server and securely exchange data. See the padlock in the web address bar of your browser? That means your browser is using a secure, encrypted link to send and receive data from our website’s server. Data-in-transit encryption is the term for this.
This is why the URL contains “HTTPS” rather than just “HTTP.” HTTPS stands for secure hypertext transport protocol. HTTP (hypertext transmission protocol) is an unreliable hypertext transport protocol. A protocol is a set of rules that regulate how data is shared between devices over networks and the internet. There are several different protocols to choose from, each with its own set of advantages and disadvantages.
When a company instals a TLS certificate on its servers, it ensures that the site’s data exchanges are encrypted using the transport layer security (TLS) protocol. Since website certificates previously used the secure sockets layer (SSL) protocol to exchange data, TLS certificates are also known as SSL certificates. (SSL is now considered obsolete.) TLS has supplanted SSL as the standard for safe data transmission.
SSL vs TLS Certificates
So, why are they often referred to as SSL certificates rather than TLS certificates? To be frank, it’s because people are resistant to change, particularly when it comes to terminology. As a consequence, you’ll still hear them referred to as SSL certificates rather than TLS certificates.
It doesn’t matter. Only keep in mind that we’re talking about TLS certificates, not SSL/TLS certificates.
Types of SSL/TLS Certificates
SSL/TLS certificates are X.509 certificates that are normally divided into two categories: validation and functionality. They can be validated with DV, OV, or EV. Depending on the functions you need, there are many different types of certificates available:
- SSL/TLS certificates for a single domain — These certificates are suitable for protecting both the WWW and non-WWW versions of a domain you manage.
- Multi-domain SSL/TLS certificates — By listing additional domains as subject alternative name (SAN) domains, you can protect several domains on a single certificate.
- Wildcard SSL/TLS certificates allow you to protect an infinite number of subdomains on a single level.
SSL/TLS certificates with multi-domain wildcards — These are the jack-of-all-trades certificates. That’s because they let you protect an infinite number of subdomains for multiple domains and SANs at all levels.
Code Signing Certificates
A code signing certificate is the next form of X.509 certificate we’ll look at. Software developers and publishers may use these certificates to prove their publisher identity. This contributes to the software’s and code’s honesty.
The certificate contributes to the initiative by allowing the software author to sign their code, script, or executable with a digital signature.
This message is an excellent way to turn off potential clients and users. Your checked publisher knowledge populates in the publisher sector thanks to a code signing certificate. This way, it’s no longer either “Unknown” or “Unverified.”
Email Signing Certificates
These X.509 certificates, also known as S/MIME certificates or personal authentication certificates (PACs), are an excellent way to send emails safely while also authenticating yourself to servers and other computers. They offer you the ability to:
- Authenticate yourself to your recipients — This means that the message was sent by you (and that you are not an imposter).
- Sign emails digitally — This shows your recipient that the data and information in your email hasn’t been changed since it was sent. It contains details about how the certificate was cryptographically signed, as well as the time and date when you signed it.
- Before you click “send,” encrypt your email data, including the message and any attachments. Data at rest encryption is the term for this. However, both you and your recipient must use an email signing certificate to send an encrypted email. This is required because before sending an encrypted email, you must obtain a copy of the recipient’s public key. (You will get this by letting the receiver send you an email that has been digitally signed ahead of time.)
These certificates are also known as personal authentication certificates because they are used for two-way authentication of users (or, more precisely, clients on their applicable devices). You may use this method to gain access to specific software, websites, servers, or computers.
Document Signing Certificates
Users may use these X.509 digital certificates to digitally sign the documents they make (Word docs, PDFs, etc.). This helps the document maker to show that the document was created by them and that it has not been changed or modified in any way. Essentially, you’re validating the document’s credibility so that everyone can trust it.
What Is the X.509 Public Key Infrastructure Set of Standards?
The cornerstone of global internet security as we know it today is public key infrastructure (PKI). The X.509 international standards are a set of guidelines that describe the format, procedures, and parties involved in the development, management, and revocation of public key digital certificates. Asymmetric cryptographic methods are also addressed, as well as how identities are related to cryptographic key pairs.
Two international standards organisations formed committees in 1988 to cooperate and develop a set of standards for dealing with the technical aspects of public key certificates. The X.509 public key infrastructure specifications are a series of standards that have been published in several versions over the last three decades.
The following two organisations were involved in the creation of the standards:
- The International Standards Organization (ISO), and
- The International Telegraph and Telephone Consultative Committee (Comité Consultatif International Téléphonique et Télégraphique, or CCITT), which later became the International Telecommunication Uninion Telecommunication (ITU-T) standardization sector.
The International Electrotechnical Commission (IEC), which has a joint committee with ISO, is now a part of the procedure. (The IEC was a part of the joint project for the 1993 edition of the X.509 standards.) All three organisations collaborate to create the international standards that companies and technology around the world use today.
Since their initial release in 1988, the X.509 public key infrastructure specifications have received about 30 updates. In October of this year, the latest version of the X.509 standards document was published.
A Summary of X.509 Certificates
To summarise the entire article, X.509 certificates (also known as public key certificates) are important for data protection and authentication over networks and the internet. X.509 certificates are used in a wide range of data exchanges and protocols. They come with various levels of validity as well as different functionalities.
X.509 certificates are now useful for a variety of activities, including:
- Individuals and organisations, as well as customers, computers, and other devices, are all authenticated.
- Ensure the confidentiality and privacy of addresses, software and code, digital records, and other data transmissions.
- Encryption is used to protect data exchanges for websites and email correspondence. This aids in the protection of data both in transit and at rest (depending on the application).
I hope this article clarifies what X.509 certificates are and how they are used by websites, companies, organisations, and individuals around the world.