Essential Data Security Principles Everyone Should Know

Table of Contents

Introduction

Data is one of our most valuable assets — and one of the most vulnerable. From personal details to business information, protecting it is critical in today’s digital world. That’s why understanding the essential security principles of data isn’t just for IT professionals — it’s something everyone should know.

In this blog, we’ll explore the core principles that keep information safe, reduce risks, and build trust in a connected world.

So, What is Security?

The word security is broad and can encompass many different methods and procedures, but when it comes to protecting company data, it is absolutely critical. Data compromises can result in severe consequences such as financial loss, reputational damage, loss of consumer trust, brand erosion, and regulatory non-compliance. When the compromise involves infrastructure software, the impact can extend even further, potentially affecting entire cities or nations. These damages are often difficult — and sometimes impossible — to fully recover from, making data security a top priority.

Some of the most common security compromises

User Compromises

Excessive privileges
Privilege abuse
Weak user authentication
Default privilege too open

Network Compromises

Firewall rules
Deep packet Inspection (DPS)
Vulnerability prevention
Denial of Service (Dos)…etc

Data Compromises

Unmanaged and unprotected sensitive data
Backup data exposure
Stolen hard disks
Unmanaged encryption keys

Vulnerability

Software bugs
Buffer overflow
SQL injection
Privileged escalation

Where is Security

Using PostgreSQL database service as an example, you can easily see that there are different types of security surrounding the PostgreSQL core service to ensure the overall security. If you set up a firewall and use TLS to communicate with PostgreSQL but does not have strong user security or data at rest encryption. You cannot say your system is 100% secured!

Data Security Principles and Methodologies

These are some of the most commonly used principles and methodologies in data security that I will go over next.

Symmetrical encryption
asymmetrical encryption (aka, public key cryptography)
block cipher mode of operations (aka, stream cipher)
key exchange algorithms
data integrity check / data authentication

Symmetrical Encryption

Symmetrical encryption is a method of securing data in which a single secret key is used for both encryption and decryption. The client uses this key to encrypt messages before sending them, and the server applies the same key to decrypt them — and vice versa. Because of its efficiency and speed, symmetrical encryption is one of the most commonly used techniques to protect data. Popular algorithms include AES (with 128, 192, or 256-bit keys), Blowfish, and DES.

Symmetrical Encryption Analogy

Symmetrical encryption is like having a shared safe with one key. Both you and your friend have a copy of the same key. When you lock a message inside the safe (encryption), your friend can use their copy of the same key to unlock it (decryption). The challenge, of course, is making sure no one else gets hold of that key — because if they do, they can open the safe just as easily.

Asymmetrical Encryption

Asymmetrical encryption uses two distinct but mathematically related keys: a public key for encryption and a private key for decryption. Unlike symmetrical encryption, it is much slower, but it provides the advantage of allowing the public key to be shared openly while the private key remains secret. This creates a secure one-way communication channel, often used for mutual authentication rather than large-scale data protection. Beyond encryption, trust is also a critical component of security, which is why protocols like Transport Layer Security (TLS) combine both symmetrical and asymmetrical methods. Common algorithms include RSA (with key sizes of 1024, 2048, or 4096 bits), Elliptic Curve, and DSA.

Asymmetrical Encryption Analogy

Think of asymmetrical encryption like a locked mailbox outside your house. Anyone can drop a letter inside because the slot is open — that’s the public key. But only you, with your unique private key, can unlock the mailbox and read the messages. This way, people can safely send you information without ever knowing your private key.

Block Cipher Mode of Operation

Block cipher modes of operation are commonly used with symmetrical encryption to process data streams block by block. Each mode has its own strengths and weaknesses, offering different ways of handling encryption and decryption. Most block cipher modes require a full 16-byte block to operate, so if the input data does not align to this size, padding (often with zeros) is added to complete the block. Popular examples include Cipher Block Chaining (CBC), Counter (CTR), and Electronic Codebook (ECB), among many others.

Refer to this post or this wiki page for pros and cons of different block cipher modes of operations

Block Cipher Mode of Operation Analogy

Imagine you’re reading a long book, but instead of reading it all at once, you break it down into pages of exactly 16 lines each. Every block cipher mode is like a different way of reading and processing those pages:

ECB (Electronic Codebook) → You copy each page as-is, independently. Simple, but if the pages look similar, patterns repeat and it’s easy to spot.
CBC (Cipher Block Chaining) → Each new page is linked to the one before it. If someone tampers with one page, it scrambles the following ones too.
CTR (Counter Mode) → You number each page and mix that number into the text, making every page look different even if the content repeats.

Just like different reading strategies, each mode has trade-offs in terms of speed, security, and error tolerance.

Key Exchange Algorithm

A key exchange algorithm is a mathematical process that allows a client and server to agree on a shared secret key without ever actually sending the key to each other. This is achieved through a series of mathematical computations and the exchange of intermediate tokens, which ultimately enable both sides to derive the same secret value independently. That shared value then becomes the session key used in symmetrical encryption algorithms to secure communication. Protocols like SSH and TLS rely on key exchange during their handshake stage to establish a session key before encrypting data. Common examples include Diffie-Hellman (DH), Elliptic Curve Diffie-Hellman (ECDH), and Ephemeral Diffie-Hellman (DHE).

Key Exchange Analogy

Imagine two people want to agree on a secret paint color, but they don’t want anyone else to know it. Each person starts with their own private paint color. They both mix their private color with the same shared base color and then exchange the mixed results. Even if someone sees the mixtures, they can’t figure out the private colors. Finally, each person adds their own private color back in, and — like magic — both end up with the exact same final shade. That shade is their shared secret key.

Data Integrity Check

A data integrity check ensures that information sent across a network arrives without being tampered with, much like using a checksum or authentication token. This process is typically performed using Message Authentication Code (MAC) or the more secure Hash-based MAC (HMAC) algorithms. Integrity checks are a critical defense against man-in-the-middle attacks, as they confirm that the data received is exactly what was sent. Both MAC and HMAC rely on hashing, which converts input of any length into a fixed-size output called a message digest (MD). While hashing is one-way — you can’t recreate the original message from the digest — the same input always produces the same output. HMAC strengthens this process by requiring an additional cryptographic key, making it more secure than standard MAC. Common HMAC algorithms include HMAC-SHA256, HMAC-SHA512, HMAC-SHA1, and HMAC-MD5.

Data Integrity Check Analogy

Imagine sending a letter sealed with a wax stamp bearing your unique symbol. When the recipient gets the letter, they check the stamp — if it’s intact and matches your symbol, they know the message hasn’t been opened or altered along the way. A MAC works like that wax seal, while an HMAC is like adding a secret ingredient to the wax recipe that only you and the recipient know. Even if someone tries to copy your stamp, they won’t be able to recreate it without the secret, ensuring the message’s authenticity.

Digital Signature

A digital signature is a security mechanism created by encrypting a representation of a message, and for efficiency, it usually operates on the message digest rather than the entire message. This means that computing a digital signature involves both hashing and asymmetrical encryption. Digital signatures provide three key guarantees: authentication, ensuring the message is from a trusted sender; integrity, confirming that the message has not been altered in transit; and non-repudiation, preventing the sender from later denying that they signed the message. Common algorithms used for digital signatures include RSA with SHA and ECDSA with SHA.

Digital Signature Analogy

Think of sending an important document in an envelope. Before mailing it, you sign it with your unique handwritten signature and seal it. When the recipient gets it, they can check two things: (1) the signature matches yours, proving the message really came from you (authentication); (2) the contents haven’t been changed since you signed it (integrity); and (3) you can’t later claim you never signed it, because your unique signature is right there (non-repudiation). In the digital world, hashing is like creating a “summary” of the document, and asymmetrical encryption is the lock and key that makes the signature verifiable.

Transport Layer Security (TLS)

Transport Layer Security (TLS) is one of the most widely used communication protocols today and is built on the foundation of multiple security principles. It employs X.509 certificates and digital signatures to ensure authenticity, integrity, and trust between client and server, while key exchange algorithms establish a session encryption key. Once the key is agreed upon, symmetrical encryption secures the actual data transmission. HTTPS is the most common protocol that relies on TLS, and because TLS integrates all these principles, both client and server must support the necessary algorithms to communicate securely. This compatibility is defined by cipher suites, which specify the combination of algorithms to be used. For example, the cipher suite TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 indicates the use of Ephemeral Diffie-Hellman (DHE) for key exchange, RSA keys for authentication, AES-256 with CBC mode for data encryption, and SHA-256 for message authentication.

A cipher suite breakdown example:

TLS Analogy

Think of TLS like sending a locked package through a courier. First, you and the recipient agree on the type of lock (key exchange). Then, you both confirm the package really comes from the right sender using a trusted ID card (digital certificate). Once the lock is set, only you and the recipient have the key (symmetric encryption), and every package also carries a tamper-proof seal (integrity check). Together, these steps ensure the delivery is private, authentic, and unaltered.

Summary

Symmetrical Encryption: Uses one shared secret key for both encryption and decryption. Fast and efficient, with algorithms like AES, Blowfish, and DES.
Asymmetrical Encryption: Uses a public key for encryption and a private key for decryption. Slower but enables secure key sharing and authentication. Common algorithms include RSA, Elliptic Curve, and DSA.
Block Cipher Modes: Methods for encrypting data in fixed-size blocks (e.g., 16 bytes). Modes like ECB, CBC, and CTR define how blocks are processed and secured.
Key Exchange Algorithms: Mathematical processes (e.g., Diffie-Hellman, ECDH, DHE) that let two parties agree on a shared key without sending it directly, forming the basis for secure sessions in TLS/SSH.
Data Integrity Checks: Ensure data hasn’t been tampered with during transmission, typically using MAC or HMAC algorithms. HMAC strengthens security by incorporating a secret key.
Digital Signatures: Combine hashing and asymmetrical encryption to provide authentication, integrity, and non-repudiation. Common algorithms include RSA with SHA and ECDSA with SHA.
Transport Layer Security (TLS): One of the most widely used communication protocols, TLS integrates all of the above principles to secure client–server communication. It uses certificates and digital signatures for trust, key exchange to establish a session key, and symmetrical encryption for efficiency.
Cipher Suites: A cipher suite defines the exact set of algorithms TLS will use for a session, specifying the key exchange, authentication, encryption method, and integrity check. For example, TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 uses DHE for key exchange, RSA for authentication, AES-256 in CBC mode for encryption, and SHA-256 for message authentication.

Together, these principles and methodologies form the backbone of modern data security, ensuring confidentiality, integrity, authentication, and trust in digital communications.

Cary Huang

Hi, I’m Cary — a tech enthusiast, educator, and author, currently a software architect at Hornetlabs Technology in Canada. I love simplifying complex ideas, tackling coding challenges, and sharing what I learn with others.