Types of Cryptography

You will learn about the main types of cryptography and how each one helps protect your data. Understanding these types is the first step to building strong cybersecurity skills.

Symmetric Encryption

Symmetric encryption is a method where the same secret key is used to both encrypt and decrypt information. You and the person you are communicating with must both have access to this key, and you must keep it secret from everyone else.

How it works:

• You use a secret key to turn readable data (plaintext) into scrambled data (ciphertext);
• The receiver uses the same secret key to turn the ciphertext back into readable data;
• If someone else gets the key, they can read your messages.

Practical cybersecurity example: Imagine you work in a company and need to send confidential files to a coworker over the internet. You both agree on a secret password before sending anything. You use this password to encrypt the files before sending. When your coworker receives the files, they use the same password to decrypt them and read the information. If anyone intercepts the files but does not have the password, they cannot read the contents.

Common symmetric encryption algorithms include AES and DES. Symmetric encryption is fast and efficient, but the main challenge is making sure only the right people have the secret key.

Asymmetric Encryption

Asymmetric encryption uses two different keys: a public key for encrypting data and a private key for decrypting it. This means you can share your public key openly, but only you have access to your private key.

This method is especially useful in cybersecurity when you need to communicate securely with someone you have never met before. For example, when you connect to a secure website (using HTTPS), your browser uses the website’s public key to encrypt information such as passwords or credit card numbers. Only the website’s private key can decrypt this data, keeping your sensitive information safe from attackers who might intercept the message.

Hashing

Hashing is a process that transforms any input data—like a password or a file—into a fixed-length string of characters, called a hash value or digest. This transformation is handled by a hash function. No matter how big or small your input is, the output (the hash) is always the same length.

Hashing is a one-way process. Once data is hashed, you cannot turn the hash value back into the original data. This makes hashing different from encryption, which is designed to be reversible.

Why is hashing important in cybersecurity?

• Protects passwords by storing only their hashes, not the actual passwords;
• Verifies file integrity by comparing hash values before and after transfer;
• Detects tampering by checking if a hash value has changed.

Practical example:

When you create an account on a website, your password is not stored as plain text. Instead, the website uses a hash function to convert your password into a hash value, such as 5f4dcc3b5aa765d61d8327deb882cf99. Only this hash is saved. When you log in, the website hashes the password you enter and compares it to the stored hash. If they match, you are granted access. This way, even if attackers steal the database, they cannot see your actual password.