The number of individuals and businesses that use the internet to transmit sensitive data is relentlessly increasing as access becomes faster and more affordable. The problem is that the internet was not designed with security in mind. Cybercriminals don’t hesitate to exploit this fact for their own profit, at the expense of those who use the internet for personal communication and business transactions.
To facilitate the secure electronic transfer of information for a wide range of network activities, a set of roles, policies, hardware, software and procedures was implemented to manage public-key encryption, and digital certificates play a crucial role in it, as well as in every modern cybersecurity strategy. So how does a digital certificate work?
What Is a Digital Certificate? The Definition
Digital certificates can be described as electronic passwords issued by a trusted third party, a certification authority (CA). They can be attached to electronic messages to verify that the sender of a message is really who he or she claims to be. Without digital certificates, it wouldn’t be possible for two parties to share their public keys in a way that can be authenticated.
Digital Certificates Versus Digital Signatures
Consider the following scenario: Alice wants to send a digitally signed message to Bob. First, Alice creates a pair of keys, a public key and a private key. She keeps her private key but shares her public key. Alice creates a message and uses her private key to sign the message and send it to Bob. When Bob receives the digitally signed message from Alice, he retrieves her public key and uses it to verify Alice’s digital signature. If Bob successfully verifies Alice’s digital signature with her public key, he has a reason to believe that the message was really created and sent by Alice and wasn’t altered in transit.
However, there is one important problem with the above-described scenario. A cybercriminal can intercept Alice’s digitally signed message and replace it with a completely different message, signed with a completely different private key, while sharing the corresponding public key. When Bob retrieves what he believes to be Alice’s public key and uses it to verify the message, everything seems to be perfectly fine even though the original message has been thrown away.
Digital certificates solve this lack of authentication by not only verifying the identity of the owner but also ensuring that the owner actually owns the public key. With digital certificates, Alice could simply attach a digital certificate to her message and send them both to Bob, who would then decode the message using the CA’s public key.
Types of Digital Certificates
There are three main types of digital certificates used on the internet to authenticate web servers and web browsers:
- Domain Validated (DV SSL) certificates: Popular among smaller businesses and website owners, a DV SSL certificate demonstrates that its holder has the right to use the associated domain name, but they don’t guarantee who the holder of the certificate is.
- Organization Validated (OV SSL) certificates: As the name suggests, an OV SSL certificate provides assurances about the holder of the certificate, giving businesses the opportunity to build trust with their customers.
- Extended Validation (EV SSL) certificates: Conforming to the X.509 standard, an EV SSL certificate proves the legal entity of the owner. It is signed by a Certificate Authority key that can issue EV certificates. EV SSL certificates are used by e-commerce websites, governments, and businesses and organizations in highly regulated industries.
All types of SSL digital certificates can be issued only by authorized CAs, such as Symantec, Comodo, GoDaddy, GlobalSign, DigiCert, StartCom, Entrust, Verizon, Trustwave, Secom, Unizeto, Buypass, and others.
In addition to SSL digital certificates, there are also code signing certificates, which are used to sign software or programmed code that is downloaded over the internet, and client certificates, which are used to identify one person to another, a person to a device or gateway, or one device to another device within a company.
Benefits of Using a Digital Certificate
Certificate-based authentication offers many benefits that make it an essential part of any modern cybersecurity strategy. The benefits include:
- Integrity: With digital certificates, it’s not possible to intentionally or unintentionally tamper with the message en route because any such attempt would be instantly discovered.
- Confidentiality: Digital certificates solve what has arguably become the biggest problem of the internet—the fact that it was not designed with privacy in mind—by allowing two parties to communicate privately across a public network.
- Identification: Digital certificates clearly identify the communicating parties and prove that they are really who they present themselves to be.
- Easy to manage: Unlike other authentication methods, digital certificates are easy to manage and can be conveniently exported from a central place to other devices to accommodate multi-user and multi-device environments.
- Easy to implement: The fact that digital certificates don’t require any additional hardware makes them very easy and cost-effective to implement.
Digital certificates help overcome the security limitations of digital signatures by identifying the owner of the public key and making it available to all parties who need to validate it. Today, there are several different types of digital certificates, and they all play an important role in any comprehensive cybersecurity strategy.
Written by: Payam Pourkhomami, President & CEO, OSIbeyond