Practical Cryptography Guide for Data Privacy
Written by  Daisie Team
Published on 10 min read


  1. What is Cryptography?
  2. How to Encrypt Data?
  3. How to Decrypt Data?
  4. Why Secure Key Management Matters?
  5. Hash Functions and Data Integrity
  6. How to Use Digital Signatures?
  7. What is Public Key Infrastructure?
  8. Secure Sockets Layer and Transport Layer Security
  9. What is Blockchain Technology?
  10. How to Secure Data with Cryptography?

Picture this: you have a secret you want to share with a friend, but you don't want anyone else to understand it if they happen to stumble upon it. So, you devise a code. Only you and your friend know this code, and voila—your secret is safe! This, in a nutshell, is what cryptography does. It's a way of keeping our digital secrets safe. It's a method that's more important than ever in our interconnected world, especially when it comes to privacy-preserving data sharing. So, let's dive into the fascinating world of cryptography, shall we?

What is Cryptography?

Cryptography is like a digital lock and key. It's a method used to protect data and information by transforming it into an unreadable format. This transformation is known as encryption. The only way to make it readable again—or decrypt it—is with a special key.

Why does this matter, you ask? Well, let's say you're sending a sensitive email to your friend. You wouldn't want just anyone to read it, right? That's where cryptography comes in. It makes sure your email is scrambled during its journey across the internet, so even if it falls into the wrong hands, they won't be able to read it. It's like your own private courier!

Here are a few key terms you'll hear often when talking about cryptography for privacy-preserving data sharing:

  • Encryption: This is the process of scrambling data so it can't be understood without the correct key. It's like turning your message into a secret code.
  • Decryption: This is the process of turning encrypted data back into its original form. It's like solving a puzzle or cracking a secret code.
  • Cipher: This is the actual method or algorithm used to perform the encryption and decryption. It's like the rules of the secret code.
  • Key: This is a piece of information used in the cipher to encrypt and decrypt data. It's like the secret password to your code.

That's cryptography in a nutshell! Stay tuned as we dive deeper into this topic and explore how it plays a crucial role in privacy-preserving data sharing.

How to Encrypt Data?

Now that we've answered the question 'what is cryptography?', let's move on to the nuts and bolts of how to actually encrypt data.

First things first, you need an encryption algorithm—remember, we said that's like the rules of your secret code. There are many different algorithms you can use, but some of the most common ones include AES (Advanced Encryption Standard), RSA (Rivest-Shamir-Adleman), and DES (Data Encryption Standard).

So, here's how you can encrypt data:

  1. Pick your Cipher: This is the algorithm you'll use to make your data unreadable. Think of it as choosing the specific rule for your secret code.
  2. Generate a Key: The key is a special piece of information that the cipher uses to transform your data. It's like the secret password to your code. The key should be random and kept secret from anyone who you don't want reading your data.
  3. Encrypt: Now, it's time to run your data through the cipher along with the key. This will turn your readable data into a jumble of characters that's difficult to understand without the right key.

And that's it! You've encrypted your data. Now, it's a bunch of mumbo-jumbo to anyone who doesn't have the right key. This is a critical step in cryptography for privacy-preserving data sharing. It ensures your data remains private, even when it's being transmitted across the vast expanse of the internet.

How to Decrypt Data?

Alright, we've covered how to turn readable data into an encrypted mess. But how do we go in the reverse direction? How do we turn that scrambled data back into something we can understand? Welcome to the world of decryption.

Decryption is pretty much the mirror image of encryption. It's like the return journey back to plain, readable data. And here's how it works:

  1. Have the Right Key: Remember that secret password we used to encrypt the data? You're going to need that again. Without the correct key, decrypting the data is going to be next to impossible.
  2. Choose the Right Cipher: You also need to know which encryption algorithm was used. This is the rulebook for the code, and you need it to understand how to reverse the process.
  3. Decrypt: Now, you put your encrypted data and the key into the cipher. The cipher follows the rules in reverse and transforms the encrypted data back into its original, readable form.

And voila! You're back where you started, with data that's readable and ready to use. But don't forget, the key to this process is, well, the key. If you lose it, you might as well say goodbye to your data. And that's why secure key management is so important in cryptography for privacy-preserving data sharing. But we'll get to that in a bit.

Why Secure Key Management Matters?

Do you remember when we talked about how important the key is in the decryption process? Well, managing these keys is a big deal in cryptography for privacy-preserving data sharing. Let's break down why it's so important:

  1. Access Control: Keys are like the passwords to your data. If someone else gets their hands on them, they can unlock your encrypted data. So, you need to make sure only the right people have access to them.
  2. Data Recovery: Ever lost your house keys and couldn't get inside? It's the same with your data. If you lose your keys, you can't get your data back. That's why you need a system to store and recover your keys.
  3. Key Rotation: Just like you might change your password every few months, it's a good idea to change your keys too. This makes it harder for anyone to gain unauthorized access to your data.

So, in a nutshell, secure key management is all about keeping your keys safe, available, and regularly updated. It's like the guardian of your encrypted data, making sure that your cryptography for privacy-preserving data sharing is as effective as possible.

Hash Functions and Data Integrity

Now, let's imagine a scenario. You've just sent your friend an encrypted message using your super secure key. But, how can your friend be sure that the message hasn't been tampered with during transmission? Enter: hash functions.

A hash function is a special type of function used in cryptography for privacy-preserving data sharing. Here's what it does:

  1. Creates a unique 'fingerprint' for your data: Just like your own fingerprint is unique to you, a hash function creates a unique 'fingerprint' for your data. This is called a 'hash'.
  2. Ensures data integrity: When your friend receives your message, they can use the same hash function to create a new 'fingerprint' from the received data. If this new 'fingerprint' matches the one you sent, they can be sure the data hasn't been tampered with.
  3. Provides one-way functionality: A hash function is a one-way street. You can create a 'fingerprint' from your data, but you can't recreate the original data from the 'fingerprint'. This makes it super secure.

So, think of hash functions as the guardians of data integrity. They're like the lie detectors of the data world, ensuring that your data remains true and hasn't been tampered with in transit. And that's super important when it comes to cryptography for privacy-preserving data sharing.

How to Use Digital Signatures?

Let's switch gears a bit and talk about digital signatures. Imagine you're sending an important document over the internet. How can the receiver be sure that it was really you who sent it? Here's where digital signatures come into play.

Using cryptography for privacy-preserving data sharing, a digital signature allows you to:

  1. Confirm your identity: Just like your handwritten signature confirms your identity on a physical document, your digital signature confirms your identity in the digital world.
  2. Ensure data integrity: Remember those hash functions we talked about earlier? Well, when you sign a document digitally, a hash function is used to create a unique 'fingerprint' of the document. This 'fingerprint' is then encrypted with your private key to create your digital signature. So, if the document is tampered with, the 'fingerprint' will change, making the signature invalid.
  3. Non-repudiation: Once you've signed a document digitally, you can't deny it later. That's because your private key, which you keep secret, is required to create your digital signature.

So, digital signatures provide a powerful way to confirm your identity, ensure data integrity, and prove your intent. They're like a digital handshake, confirming that it's really you on the other side of the screen. And that's a big plus when it comes to cryptography for privacy-preserving data sharing.

What is Public Key Infrastructure?

Now, let's move on to another important topic: Public Key Infrastructure, or PKI for short. PKI is like the backbone of cryptography for privacy-preserving data sharing. But why? Let me explain.

PKI is a system that helps us manage and distribute digital certificates. Think of a digital certificate as an online ID card. Just like your ID card has your photo and details, a digital certificate has your public key and some information about you. And just like your ID card is issued by a trusted authority, a digital certificate is issued by a Certificate Authority (CA).

Here's how it works:

  1. You create a pair of keys: a private key that you keep secret, and a public key that you share with the world.
  2. You send your public key, along with some information about you, to a CA.
  3. The CA verifies your information and then uses its own private key to sign your public key and your information. This creates your digital certificate.
  4. Now, anyone can use the CA's public key to verify your digital certificate and thus, your public key.

So, PKI ensures that we can trust the public keys we use. Without PKI, it would be like trying to find a friend in a crowded stadium without knowing what they look like. With PKI, it's like having a trusted mutual friend point out your friend to you. And that's why PKI is so important for cryptography for privacy-preserving data sharing.

Secure Sockets Layer and Transport Layer Security

Now, let's talk about Secure Sockets Layer (SSL) and Transport Layer Security (TLS). You've probably heard of these terms — they're common in the world of internet security. But what exactly do they have to do with cryptography for privacy-preserving data sharing? Quite a lot, actually!

SSL and TLS are protocols — or sets of rules — that provide security for internet communications. They do this by encrypting the data that is sent between your computer and the server. This keeps the data private and ensures that no one else can read it. Kind of like a secret conversation between you and your best friend, right?

But how do SSL and TLS work? Here's a simplified version:

  1. Your computer and the server agree to use SSL or TLS for their conversation.
  2. Your computer verifies the server's digital certificate (remember, the online ID card we talked about before?). This ensures that it's really talking to the server it thinks it's talking to.
  3. Your computer and the server use their private and public keys to create a shared secret key. This key is used to encrypt and decrypt the data they send to each other.
  4. Your data is sent over the internet, safe and secure from prying eyes.

So, SSL and TLS are like the protective bubble around your data when it travels over the internet. They're vital for cryptography for privacy-preserving data sharing because they keep your data safe while it's in transit.

What is Blockchain Technology?

Have you heard about this thing called blockchain? It sounds pretty high-tech and complicated, right? But don't worry—you're about to understand what it's all about. Let's break it down in the simplest terms possible.

Imagine a chain of blocks (hence the name 'blockchain'). Each block contains information, like a transaction or a contract. Now, what makes this chain super special is that once a block joins the chain, you can't change its information. It's kind of like writing in permanent marker—there's no erasing it. This makes blockchain a secure way to store data.

But here's where it gets even cooler. This chain doesn't live in one place like a computer or a server. Instead, it's distributed across a network of computers, all keeping a copy of the chain. This means if one computer goes down, the chain is still safe and intact on all the other computers. Super smart, right?

So, why are we talking about blockchain in a guide about cryptography for privacy-preserving data sharing? Because each block is encrypted. Remember that secret code we talked about earlier? That's right—cryptography. Blockchain uses cryptography to secure the data in each block, making it a powerful tool for data privacy.

In summary, blockchain technology uses cryptography to secure data and ensures data integrity and privacy. It's like a superhero of data protection, playing a big role in the world of cryptography for privacy-preserving data sharing. Now, isn't that something?

How to Secure Data with Cryptography?

Alright, let's get to the fun part! How can you use cryptography to secure your data? It might sound like a job for a secret agent, but I promise, it's something you can learn to do. Let's dive in!

First off, you need to choose the right encryption algorithm. It's like choosing the best type of lock for your front door. There are tons of algorithms out there—AES, RSA, Triple DES, to name a few. But don't worry, you don't need to understand the math behind them (phew!). You just need to know that they are different types of locks, and some are stronger than others.

Next, you'll need a key. Just like you need a key to open a lock, you need a key to decrypt your data. And remember, never ever share your key. It's like giving someone the password to your email account—definitely not a good idea!

Now, let's talk about secure key management. It's one thing to have a key, but you also need to keep it safe. That's where secure key management comes in. It's like a safe for your key. It ensures that only authorized people can access the key. Again, no sharing!

Lastly, you'll want to use a hash function. This is like a special seal that verifies your data hasn't been tampered with. It takes your data and turns it into a unique string of characters. If even one tiny thing changes in your data, the hash will also change. So, it's a great way to keep an eye on your data's integrity.

There you have it! That's a basic rundown of how to use cryptography for privacy-preserving data sharing. Remember, the world of cryptography is vast and constantly evolving. So, keep learning, stay curious, and most importantly, keep your data safe!

If you want to delve deeper into the world of cryptography and data privacy, be sure to check out the workshop 'Crypto For Creators, Part 1: The Backbone Of The Digital Economy' by Tom Glendinning. This workshop will provide you with a solid understanding of cryptography and its crucial role in ensuring data privacy in the digital economy.