Comprehensive Guide: Cryptography & Public Key Infrastructure
Written by  Daisie Team
Published on 9 min read


  1. What is Cryptography?
  2. Types of Cryptography
  3. How Cryptography Secures Data
  4. What is Public Key Infrastructure?
  5. How Public Key Infrastructure Works
  6. Components of Public Key Infrastructure
  7. Advantages of Public Key Infrastructure
  8. Challenges and Solutions in Public Key Infrastructure

Imagine you're sending a letter to a friend. You don't want anyone else to read it, so you lock it inside a box. Now, imagine that box is a piece of data, and the lock is a complex code. That's essentially what cryptography is - a method to keep your data safe and secure. It's a critical part of how the internet works, especially when it comes to things like online banking, email, and even just browsing the web. And one of the most important parts of cryptography is something called Public Key Infrastructure, or PKI. Stick around, and we'll break down what cryptography and PKI are, how they work, and why they're so important for keeping your data safe and sound.

What is Cryptography?

At its core, cryptography is a way to secure communication. It's like a secret language that only you and the person you're speaking to understand. This secret language is made possible through the use of algorithms or codes. The word cryptography itself comes from the Greek words 'kryptos' meaning hidden and 'graphein' meaning to write.

When you use cryptography, you're transforming plain, understandable information into something that looks like complete gibberish. This transformation is done using a key - a bit like the key you use to lock and unlock your front door. Once the information has been transformed, it can only be read by someone with the correct key. This is how cryptography secures your data.

So, how does this work in practice? Let's take a look at an example. Say you're sending an email to a friend. You don't want anyone else to read it, so before you hit send, you 'encrypt' it, turning the message into that gibberish we mentioned earlier. Now, if anyone intercepts the email while it's being sent, all they see is a bunch of random characters. But once it arrives at your friend's inbox, it's 'decrypted' back into the original message, and they can read it as if nothing happened.

And that's the basics of cryptography! It's all about keeping your data secure by transforming it into something that only the intended recipient can understand. But remember, this is just the tip of the iceberg. There are different types of cryptography and an entire infrastructure built around it, known as Public Key Infrastructure or PKI, which we'll explore next.

Types of Cryptography

Just like there are different types of locks, there are different types of cryptography. Each type has its strengths, weaknesses, and best uses. The three main types of cryptography you'll hear about are symmetric cryptography, asymmetric cryptography, and hash functions.

Symmetric Cryptography: This is the simplest form of cryptography and it's probably what you first thought of when we mentioned a secret language. In symmetric cryptography, the same key is used to both encrypt and decrypt the data. It's a bit like having a single key that can both lock and unlock a box. It's fast and efficient, but there's a catch: you have to find a safe way to share the key with the person who needs to decrypt the data.

Asymmetric Cryptography: This is where things get a bit more complex. In asymmetric cryptography, two keys are used: one to encrypt the data, and a different one to decrypt it. It's like having one key to lock the box and a separate key to unlock it. This solves the problem of key distribution that symmetric cryptography faces, but it's a bit slower because of the extra complexity. This is where Public Key Infrastructure (PKI) comes in, which we'll talk about a bit later.

Hash Functions: The third type of cryptography is a little different. Hash functions transform data into a fixed size string of characters, which typically looks like a random sequence of letters and numbers. The unique thing about hash functions is that they're a one-way street - once data has been transformed into a hash, it can't be turned back into the original data. This is super useful for storing things like passwords, where you want to verify that the correct password has been entered, without actually storing the password itself.

There you have it - a quick run-down of the main types of cryptography. Each type has its place and is used for different applications, but they all share a common goal: keeping your data secure. Now, let's dig into a key part of asymmetric cryptography - Public Key Infrastructure (PKI).

How Cryptography Secures Data

Cryptography, in essence, is like a magic cloak of invisibility for your data. But how does it actually keep your data safe from prying eyes? Let's break it down.

First, cryptography transforms your data into something unreadable. It's like turning a crystal clear pond into a murky mess where you can't see anything. This is the process of encryption. Imagine you have a secret message—let's say, "The quick brown fox". In the world of cryptography, this is what we call plaintext. With the magic of cryptography, your message becomes something like "QEB NRFZH YOLTK CLU GRJMP LSBO QEB IXWV ALD". This is what we call ciphertext.

Now, to anyone else, this encrypted message is gobbledygook. But to the person with the right key, it's as clear as day. The process of turning the ciphertext back into understandable plaintext is what we call decryption. In the world of cryptography, the key is just as important as the lock!

But wait, there's more! Cryptography doesn't only disguise your data. It also makes sure that it hasn't been tampered with in transit. This is where hashing and digital signatures come in. They're like a tamper-proof seal for your data. Any changes, however small, will break the seal and set off alerts.

To sum it up, cryptography secures data by making it unreadable to anyone without the right key and by ensuring that it arrives exactly as it was sent. It's an amazing tool in our digital world, and it's the backbone of Public Key Infrastructure (PKI).

What is Public Key Infrastructure?

After understanding cryptography, let's dive into a term that often goes hand in hand with it, the Public Key Infrastructure, or PKI for short. But what exactly is it?

Imagine you're in a bustling city, filled with thousands of locks and keys. Now, keeping track of which key opens which lock can be a real headache, right? This is where PKI steps in. It's like a trusted locksmith in this city of locks and keys, making sure that the right key gets to the right lock.

In technical terms, PKI is a system used to create, manage, distribute, use, store, and revoke digital certificates. It provides a framework that enables encryption and digital signature services across networks. If cryptography is a magic cloak for your data, then PKI is the magician's assistant, making sure the cloak gets to the right person.

PKI plays a pivotal role in securing digital communication and ensuring data integrity. It's like a superhero, protecting the digital world from villains like hackers and cybercriminals. In the world of cryptography and PKI, PKI is the unsung hero, quietly keeping our data safe and secure.

So next time you're browsing the web, sending an email, or making an online purchase, remember that there's a whole system working behind the scenes to keep your data safe. That's the power of cryptography and PKI!

How Public Key Infrastructure Works

Now that we know what PKI is, let's take a peek at how it works. It's like watching a magic trick unfold, except this time we get to see behind the curtain.

PKI uses a pair of keys—a public key and a private key. Think of it as a two-key system to a safe. The public key is available to everyone (hence the name), but the private key is kept secret, just like the personal key to your home.

Here's the cool part: data encrypted with one key can only be decrypted by the other key. So, if you lock the safe with the public key, only the private key can open it, and vice versa. This is the basis of how PKI secures data—it's a clever game of lock and key!

But how does this game of lock and key play out in the digital world? Let's go through the steps:

  1. First, when two devices need to communicate securely, they exchange public keys.
  2. Next, when one device wants to send data, it encrypts the data using the recipient's public key.
  3. Now, only the recipient's private key can decrypt the data.
  4. Once the data is received, the recipient uses their private key to unlock the data and voila, the data is revealed!

This is the magic of PKI in action. It's like a digital handshake between devices, ensuring that data is only seen by the intended recipient. So, the next time you're sending a confidential email or making an online purchase, give a silent nod to the genius of cryptography and PKI, working tirelessly to keep your data secure.

But remember, this is just a simple explanation. The actual workings of PKI are far more complex and involve many other elements. But hey, we're just getting started, right?

Components of Public Key Infrastructure

Just like a well-oiled machine, PKI is made up of several parts working together to achieve one common goal—secure communication. Let's break down these components and see what each one does.

  1. Certificate Authority (CA): This is the trusty middleman of the PKI world. The CA issues digital certificates, which are like digital passports. They verify the identity of the certificate holder and link them with their public key.
  2. Registration Authority (RA): The RA is like the gatekeeper. It verifies the identities of entities (like users or devices) before the CA issues them a certificate. It's like a bouncer checking IDs at the door.
  3. Central Directory: This is where all the issued certificates and public keys are stored. It's like a digital phone book where devices can look up each other's public keys.
  4. Certificate Management System: This system takes care of the lifecycle of a certificate. From issuing and renewing to revoking certificates, it handles it all.
  5. Certificate Policy: This is a set of rules that governs how certificates are used and who can use them. Think of it as the rule book for the PKI game.

These components, when functioning together, create the secure environment necessary for cryptography and PKI to thrive. It's a complex system, but when you break it down, it's just like any other well-structured team—each member has a role to play to ensure everything runs smoothly.

So next time you're securely browsing a website or sending a confidential email, remember there's an entire infrastructure working behind the scenes to keep your data safe. It's not magic—it's cryptography and PKI!

Advantages of Public Key Infrastructure

Now that you understand the basics of how cryptography and PKI work and the different components involved, let's explore why it's such a big deal. Here are some of the key benefits of using PKI:

  1. Improved Security: PKI is like a digital lock and key system. It ensures that only the intended recipients can access the information, keeping it safe from prying eyes. Secure communication? Check!
  2. Authentication: Remember the digital certificates we talked about? They're a bit like online ID cards. They confirm that an entity is who they claim to be. So, you can trust that you're communicating with the right person or system.
  3. Data Integrity: With PKI, you can be sure that the data you're receiving hasn't been tampered with during transit. No funny business here!
  4. Non-Repudiation: This is a fancy way of saying that with PKI, you can prove that a specific entity sent a message. This means that a sender can't deny having sent a message—kind of like a digital paper trail.

In a nutshell, PKI is the unsung hero of secure communication. It offers a robust security framework that's essential in our increasingly digital world. Whether you're browsing your favourite website, making an online purchase, or emailing a confidential document, you have PKI to thank for keeping your data safe and secure.

Challenges and Solutions in Public Key Infrastructure

Despite its many advantages, implementing cryptography and PKI is not without its challenges. But don't worry, where there's a problem, there's a solution. Let's dive into some of these challenges and how they can be solved:

  1. Key Management: Managing digital keys in a PKI is a bit like being a locksmith for the internet. It's tricky, especially as the number of keys grows. However, using automated key management systems can help keep track of all these keys and reduce the likelihood of human error.
  2. Infrastructure Complexity: PKI systems can be complex to set up and maintain. You need to manage certificates, keys, and different system components. But, with the right expertise and tools, this complexity can be tamed. It's like learning to juggle—you start with one ball and gradually add more as you get better.
  3. Cost: Setting up a PKI can be costly, especially if you're starting from scratch. But think about it this way: the cost of a data breach can be far more damaging. Investing in a robust PKI is like buying insurance for your data—it's worth the price tag.
  4. Revocation of Certificates: Sometimes, certificates need to be revoked before they expire, such as when a key is compromised. This can be a complex process, but with a solid revocation strategy in place, it becomes manageable. It's like having a plan B for when plan A doesn't work out.

As you can see, while there are challenges associated with implementing and managing a PKI, there are also solutions available. Like any good superhero, PKI has its weaknesses, but with the right strategies in place, it remains a powerful tool in the fight for data security.

If you found this comprehensive guide on cryptography and public key infrastructure intriguing and want to learn more about the connection between cryptography and the creative industry, check out the workshop 'Crypto For Creators, Part 1: The Backbone Of The Digital Economy' by Tom Glendinning. This workshop will provide you with insights on how cryptography plays a crucial role in the digital economy and how it can impact creators like you.