All about public key certificate

Using a public key certificate, an organisation may securely send its public key for use in asymmetric cryptography. If Raju creates his own private and public keys, he cannot pose as Shyam and send Bobby his public key by utilising a public key certificate. Although Bobby will be able to communicate with Raju, he will think Shyam is getting his information.

Consider a public key certificate as the electronic equivalent of a passport. It serves as the bearer’s identity and is issued by a reputable institution. A Certificate Authority is a reputable company that issues public key certificates (CA). 

The CA is comparable to a public notary. A CA certificate may only be obtained by presenting identification. Once the CA is certain that the application truly represents the company it claims to represent, the CA signs the certificate, attesting to the accuracy of the data it contains.

Public key certificate: How does a public key certificate function?

•       A public key infrastructure (PKI) system that employs encryption to safeguard messages and data includes public key certificates as one of its components.
•       A pair of encryption keys—one public and one private—are used by a public key certificate.
•       While the private key is a specific key that is kept hidden, the public key is made available to everyone who wishes to check the identity of the certificate holder.
•       This makes it possible for the certificate holder to digitally sign papers, emails, and other information without allowing a third party to assume their identity.
•       Public key encryption, dependable outsiders like the CA, the registration authority, and the certificate database or store are the four fundamental PKI constituents.

 

Public key certificate: What are a public key certificate’s components?

Issuer

The certificate’s issuing authority (CA). Users can trust certificates if they have confidence in the CA that issued them and the certificates are legitimate.

Validity period

There is an expiration date on a certificate. When determining if a certificate is still valid, this date should be checked.

The subject line includes details about the organisation the certificate is for.

The public key of the subject

The subject’s public key is the main piece of information that the certificate offers. In order to guarantee the accuracy of this key, all the additional fields are offered.

Signature

The CA that issued the certificate digitally signs the certificate. The signature confirms the certificate’s authenticity and is produced using the CA’s private key. TLS does not support nonrepudiation since only the certificate is signed, not the data transferred in the TLS transaction.

 

Public key certificate: What sorts of public key certificates exist?

Public key certificates come in three varieties: client certificates, code signing certificates, and transport layer security (TLS/SSL) certificates.

1.  Certificate for TLS/SSL

To guarantee private and encrypted communication with its customers, a TLS/SSL certificate resides on a server, such as an application, mail, or web server. The certificate offers authentication so that the server may transmit and receive clients’ encrypted messages. A TLS/SSL certificate’s availability is indicated by the Hypertext Transfer Protocol Secure (HTTPS) prefix at the beginning of a Uniform Resource Locator (URL) or web address. It has three different forms:

–        Validated domain

Any website can use a domain-verified certificate, which is a rapid validation approach. It may be acquired for a low cost and granted in only a few minutes.

–        Validated by organisation

This provides straightforward company authentication and is ideal for businesses that engage in e-commerce online sales.

–        Additional validation

This provides complete corporate authentication, which is necessary for bigger enterprises or any company working with extremely sensitive data. It delivers the greatest degree of trust, security, and verification and is often utilised by firms in the financial sector.

 

 

2.  Code signing certification

Software or files acquired from the internet can be verified as genuine using a code signing certificate. The programme is signed by the publisher or developer to guarantee its authenticity to consumers who download it. To demonstrate that files have not been altered, this is helpful for software vendors that make their products available on independent websites.

3.  Consumer certificate

An individual user can be recognised by another user, machine, or machine-to-machine using a client certificate, which is a digital ID. Email is a typical instance of this, where the recipient verifies the sender’s digital signature on a communication before it is sent. User access to secured databases can also be facilitated using client certificates.

 

Public key certificate: Advantageous characteristics

With the volume and sophistication of cyber assaults continuing to rise, public key certificates are becoming more and more crucial. Some of the main advantages of public key certificates are:

Security

Digital certificates encrypt both internal and external connections to prevent hackers from spying on and stealing crucial information. For instance, to prevent data from being intercepted by an attacker, a TLS/SSL certificate encrypts data transmitted between a web server and a web browser.

Scalability

Businesses of different sizes and shapes may benefit from the same level of encryption thanks to public key certificates. They may be used to protect user devices and are extremely scalable, making it simple to issue, revoke, and renew them in a matter of seconds. They are also administered through a centralised platform.

Authenticity

Digital certificates are crucial for ensuring the legitimacy of internet communication in the age of ubiquitous cyberattacks. They ensure that users’ communications will always—and only—be received by the intended receiver. TLS/SSL certificates are used to encrypt websites, S/MIME certificates are used to encrypt emails, and document-signing certificates can be used to exchange digital documents.

Reliability

Public key certificates may only be issued by publicly reputable CAs. To ensure that victims who use a public key certificate cannot be duped by hackers or bogus organisations, obtaining one involves thorough verification.

Public trust

A public key certificate may be used to verify the legitimacy of documents and communications as well as websites. This fosters public confidence and reassures customers that they are working with a legitimate business that prioritises their security and privacy.

 

Who is eligible to request public key certificates?

Individuals, businesses, and websites can all seek public key certificates. They accomplish this by supplying a public key and the information to be verified through a certificate signing request. A publicly reputable CA signs the data with a key that establishes a chain of trust from the certificate, validating it.

As a result, the certificate may be used to validate a website’s credentials, confirm the legitimacy of a document, or authenticate clients.

Public key certificate: Drawbacks

–        Lack of control over the encryption key is the main drawback of public key certificates.

–        This implies that the certificate cannot be revoked even if it has been hacked. The certificate may be stolen through server hacking, and the public key included within the certificate could then be used to decode any data that had been encrypted using the public key.

–        When a web certificate is altered, a browser does not issue a warning, and a fake root certificate can be installed.

 

 

FAQs

What distinguishes a public key certificate from a digital signature?

A digital signature is a hashing technique that employs a numeric string to offer authenticity and authenticate identification, whereas a public key certificate is a file that validates the identity of a device or person and permits encrypted communications.

What are the main responsibilities of a certification body?

A CA performs the following duties: the creation of key pairs, the issuance of public key certificates, their publication, their verification, and their revocation.