How cryptography protects your digital world: from ancient times to quantum computers

Every day, you trust cryptography, often without even noticing it. When you log into a website, make an online payment, or send a private message – all of this works thanks to an invisible but extremely powerful science. It is not just a technical tool; cryptography is the foundation of trust in the digital world. In this article, we will explore how it functions, how it has developed, what algorithms underpin it, and how it shapes our security—from personal correspondence to the global blockchain infrastructure.

What Cryptography Really Does

Cryptography is the science of methods for ensuring confidentiality, data integrity, authentication, and non-repudiation. However, behind these scientific terms lie very practical tasks.

Imagine: you have a secret message, and you need to guarantee that only the recipient can read it. Early people solved this problem simply – by replacing letters with others. This was the first step in cryptography. Today, it operates with complex mathematical algorithms, but the essence remains the same: transforming information so that it is inaccessible to outsiders.

The main goals of cryptography boil down to four key functions:

Confidentiality – only authorized persons can access the information. Your encrypted message remains private.

Data Integrity – assurance that information has not been altered during transmission or storage, neither accidentally nor intentionally.

Authentication – verifying the authenticity of the data source. How to know that the message was sent by the person it claims to be?

Non-repudiation – a person cannot later deny having sent a message or performed a transaction.

In the modern world, secure financial operations, protected government communications, confidentiality of correspondence, and the functioning of innovative technologies such as blockchain and smart contracts are impossible without cryptography.

Where Cryptography Already Protects You

Cryptography is everywhere, even if you don’t see it:

HTTPS and secure web browsing. The padlock icon in the browser’s address bar indicates: your connection to the site is secure. This works thanks to TLS/SSL protocols, which encrypt everything transmitted between you and the server – passwords, credit card data, personal information.

Secure messengers. Signal, WhatsApp, and other apps use end-to-end encryption. This means: even the messenger operator cannot read your conversation, only you and the recipient.

Home Wi-Fi networks. Protocols WPA2 and WPA3 encrypt your traffic from the network administrator and eavesdroppers.

Bank cards. Microchips on cards contain cryptographic keys and authenticate transactions each time, preventing cloning.

Digital signatures. Orders, contracts, official documents are digitally signed, guaranteeing their authenticity and immutability.

Blockchain and cryptocurrencies. Cryptographic hash functions and digital signatures ensure security, transparency, and immutability of transactions. Understanding the basics of cryptography is necessary to navigate the world of digital assets.

VPNs and anonymity. Encryption of internet traffic when connecting through public networks keeps your activity hidden from observers.

Cryptography vs. Encryption: The Important Difference

These words are often used as synonyms, but that’s inaccurate.

Encryption is a process, a way of transforming readable text into an unreadable format. You input information, an algorithm processes it, and an incomprehensible string of characters emerges. Decryption is the reverse operation.

Cryptography is a much broader science. It includes the development of encryption algorithms but also encompasses:

• Cryptanalysis – the science of decrypting ciphers and finding vulnerabilities.
• Protocols – developing secure systems of interaction (TLS, key exchange protocols).
• Key management – secure creation, distribution, and storage of cryptographic keys.
• Hash functions – creating “digital fingerprints” to verify integrity.
• Digital signatures – methods of authentication and authorship confirmation.

Encryption is one of the tools of cryptography, but not the entire field is reduced to encryption.

How Cryptography Evolved Over Millennia

The history of cryptography is rich with dramatic moments, brilliant ideas, and fierce competitions between cipher creators and their attackers.

Ancient examples and the Middle Ages

In Ancient Egypt (around 1900 BCE), people used non-standard hieroglyphs to hide the meaning of inscriptions. In Ancient Sparta (5th century BCE), warriors used a scytale – a stick of a certain diameter, wrapped with a strip of parchment. The message was written along the stick, but after unwinding the strip, the text appeared as a meaningless set of letters. Only someone with a stick of the same diameter could read it.

One of the most famous ancient ciphers is the Caesar cipher (1st century BCE). Each letter was simply shifted forward by a few positions in the alphabet. Simple but effective – until Arab scholars led by Al-Kindi (9th century CE) developed frequency analysis. They understood: if you count how often letters appear in the ciphertext, you can guess which letters they are in the original.

In Europe, the Vigenère cipher (16th century) gained popularity. At that time, it was considered unbreakable. It used a keyword that determined the shift for each letter. However, the 19th century brought its decryption – Charles Babbage and Friedrich Kasiski demonstrated how to crack it.

20th century: the era of machines

World War I highlighted the importance of cryptography. Deciphering Zimmermann telegrams significantly contributed to the US entering the conflict.

World War II became the golden age of mechanical cryptography. The German Enigma machine was considered practically unbreakable. But Polish and British mathematicians, including the legendary Alan Turing at Bletchley Park, developed methods to break it. Decoding Enigma messages influenced military operations. The Japanese had their own machine, Fugue, and Americans learned to crack it as well.

The computer revolution

Computers changed everything. In 1949, Claude Shannon published the foundational paper “A Mathematical Theory of Communication,” which laid the theoretical groundwork for modern cryptography.

The 1970s introduced DES (Data Encryption Standard) – the first widely adopted standard. It was secure for its time but became vulnerable as computational power increased.

A real revolution was asymmetric cryptography (1976). Whitfield Diffie and Martin Hellman proposed a concept that seemed impossible: what if you have two different keys – one for encryption (public), one for decryption (private)? Soon, a practical algorithm appeared – RSA (Rivest, Shamir, Adleman), which is still in use today.

Types of Cryptography That Shape the Present

There are two main approaches to encryption:

Symmetric cryptography

One key is used for both encryption and decryption. It’s like a regular lock and key – whoever has the key, can open.

Advantages: Very fast, ideal for large data volumes (video streams, databases, archives).

Disadvantage: The problem of secure key transfer. If the key is intercepted, all security collapses. Each pair of participants needs its own key.

Examples of algorithms: AES (the current global standard), 3DES, Blowfish, GOST 28147-89, GOST R 34.12-2015 (Russian standards).

Asymmetric cryptography

Two mathematically related keys: a public and a private one. Anyone can encrypt information with the public key, but only the owner of the private key can decrypt it.

Analogy: A mailbox. Anyone can put a letter in, but only the owner can open it.

Advantages: Solves the problem of secure key exchange. Enables digital signatures. The basis for secure e-commerce and cryptographically protected protocols (SSL/TLS).

Disadvantage: Much slower than symmetric encryption. Impractical for encrypting large data volumes directly.

Examples: RSA, ECC (Elliptic Curve Cryptography – more efficient), Diffie-Hellman.

How they work together

In practice, a hybrid approach is often used. TLS/SSL (the basis of HTTPS) works like this: the asymmetric algorithm securely exchanges keys, then the fast symmetric algorithm (AES) encrypts the main traffic.

Cryptographic Hash Functions: Digital Fingerprints

A hash function is a mathematical operation that transforms data of any size into a fixed-length string (hash, fingerprint).

Important properties:

Pre-image resistance: It’s impossible to recover the original data from the hash. Like compression that cannot be reversed.

Determinism: The same data always produces the same hash. Even changing one symbol drastically changes the hash.

Collision resistance: It’s practically impossible to find two different data sets with the same hash.

Applications: Verifying file integrity (downloaded a program – compare hash), secure password storage (hashes stored in the database, not the passwords themselves), digital signatures, and especially – blockchain (linking blocks, identifying wallet addresses).

Standards: SHA-256, SHA-512 (widely used), SHA-3 (latest), GOST R 34.11-2012 “Streebog” (Russian standard).

The Threat of Quantum Computers and New Solutions

The advent of powerful quantum computers poses an existential threat to most modern asymmetric algorithms (RSA, ECC). A quantum computer running Shor’s algorithm can crack these systems in reasonable time.

The world responds with two directions:

Post-quantum cryptography. New algorithms are being developed (based on lattices, codes, hashes, multivariate polynomials), resistant to both classical and quantum attacks. NIST is actively standardizing such algorithms.

Quantum cryptography. Not for calculations, but for key protection. Quantum key distribution (QKD) allows two parties to exchange keys so that any interception attempt will be detected. Technologies already exist and are tested in pilot projects.

Cryptography vs. Steganography

These two concepts are often confused:

Cryptography makes messages unreadable, but everyone can see that something is there.

Steganography hides the very existence of the message. Secret text can be hidden inside a photo, audio file, or even in the text of an article. At first glance – a normal image, but in fact, it contains an encrypted document.

It’s optimal to combine both: first encrypt the message (cryptography), then hide it (steganography). Two layers of protection.

How Cryptography Protects You Every Day

Internet and secure connections

TLS/SSL (the basis of HTTPS): When you log in, pay, transmit data – all of this travels through an encrypted channel. The protocol authenticates the server (checks the certificate), exchanges keys, and encrypts traffic with AES.

E2E in messengers: Signal, WhatsApp, and others use end-to-end encryption. Your correspondence is visible only to you and the recipient.

DNS over HTTPS/TLS: Hides which sites you visit from operators and observers.

Financial security

Online banking: Session protection, database encryption, multi-factor authentication with cryptographic elements.

Bank cards (EMV): Microchips contain cryptographic keys and verify the card’s authenticity during each transaction.

Payment systems: Visa, Mastercard, Mir use complex cryptographic protocols for authorization and protection.

Digital signatures and documents

A cryptographic mechanism that confirms authorship and integrity of a document. The document’s hash is encrypted with a private key; the recipient decrypts it with the public key and compares. If hashes match: the document is indeed from the author and has not been altered.

Applications: legally significant documents, government reports, electronic auctions.

Corporate system security

1C and Russian platforms often integrate with CryptoPro CSP or VipNet CSP for:

• Submitting electronic reports with electronic signatures
• Electronic document exchange with partners
• Participating in government procurement
• Encrypting critical data

Use of GOST standards is mandatory for state information systems and systems handling state secrets.

Blockchain and cryptocurrencies

Cryptography is the heart of blockchain. Hash functions link blocks, digital signatures authenticate transactions. Understanding cryptography is essential for understanding the security of digital assets.

Cryptography in Different Countries

Russia: tradition and standards

Russia has a deep mathematical school in cryptography. The country has its own cryptographic standards (GOST), developed by the state:

• GOST R 34.12-2015: Symmetric encryption (“Kuznechik” and “Magma”).
• GOST R 34.10-2012: Digital signatures on elliptic curves.
• GOST R 34.11-2012: Hash function “Streebog.”

Use of GOSTs is mandatory when working with state secrets and often required by regulators.

FSB Russia licenses cryptographic activities and certifies tools. FSTEC regulates issues of technical information protection.

Russian companies (CryptoPro, InfoTeKS, Kod Bezopasnosti) develop advanced solutions in information security.

USA: the producer of global standards

NIST (National Institute of Standards and Technology) sets global standards. NIST developed AES, the series of SHA, and is currently conducting a competition for post-quantum algorithms.

NSA historically participated in cryptography development, but its influence on standards often causes debate.

American universities (MIT, Stanford) and companies are leaders in cryptographic research.

Europe: privacy and sovereignty

GDPR requires adequate protection of personal data, where cryptography is a key tool.

ENISA (European Union Agency for Cybersecurity) promotes standards and best practices.

European countries (Germany, France, UK) have strong research centers.

China: technological independence

China actively develops its own cryptographic algorithms (SM2, SM3, SM4) for technological sovereignty.

The country strictly regulates cryptography and invests in post-quantum technologies and quantum research.

International Standards Connecting the World

• ISO/IEC: Global standards for IT and security.
• IETF: Internet standards (TLS, IPsec, PGP).
• IEEE: Cryptographic aspects of network technologies.

National standards are important, but international ones ensure compatibility and trust.

Career in Cryptography: The Future for Researchers

Demand for specialists is growing exponentially.

What experts are sought

Cryptographer (researcher): Develops new algorithms, studies their resilience, researches post-quantum cryptography. Requires deep knowledge of mathematics – number theory, algebra, complexity theory.

Cryptoanalyst: Analyzes ciphers, finds vulnerabilities. Works in security (for improvement) and in special services.

Information security engineer: Implements cryptographic systems in practice – VPNs, PKI, encryption systems, key management.

Secure software developer: Knows how to properly use cryptographic libraries and APIs to protect applications.

Penetration tester: Finds vulnerabilities in systems, including cryptography errors.

Necessary skills

• Mathematics (foundation)
• Knowledge of algorithms and protocols
• Programming (Python, C++, Java)
• Network technologies and operating systems
• Analytical thinking and attention to detail
• Continuous self-improvement

Where to study

Universities: MIT, Stanford, ETH Zurich, and others offer strong programs.

Online: Coursera, edX, Udacity – courses from leading professors.

Practice: Platforms like CryptoHack, CTF competitions develop skills.

Books: Simon Singh “The Code Book,” Bruce Schneier “Applied Cryptography.”

Career opportunities

Jobs are found in:

• IT companies
• Financial institutions (banks, payment systems, crypto platforms)
• Telecommunications
• Government agencies
• Defense industry
• Consulting firms

Salaries in cybersecurity are higher than the average IT market, especially for experienced specialists. The development pace is intense, challenges constantly change.

Frequently Asked Questions

What to do if a cryptography error occurs?

A “cryptography error” is a general message that appears in various contexts. Causes: expired license, certificate issues, version incompatibility, incorrect settings.

Actions:

1. Restart the program/computer
2. Check the certificate’s validity period
3. Update the system, browser, cryptographic hardware
4. Verify settings according to documentation
5. Try a different browser
6. Contact certification authority or technical support

What is a cryptographic module?

A hardware or software component designed specifically for cryptographic operations: encryption, decryption, key generation, hash calculation, creation of digital signatures.

How to teach a child cryptography?

• Study its history (Caesar and Vigenère ciphers – a great start)
• Solve cryptographic puzzles (CryptoHack, CTF competitions)
• Read popular books about coding and security
• Implement simple ciphers in your programming language
• Take online beginner courses on Stepik or Coursera
• Master basic mathematics (algebra, number theory)

Summary

Cryptography is not just a set of formulas; it is the foundation of trust in the digital world. From personal messages to international financial systems, from state protection to blockchain – it shapes the security of all digital processes.

We traced its evolution from ancient sticks and simple letters to quantum technologies. Understanding the basics of cryptography is no longer a luxury – it is a necessity for anyone serious about their digital security.

Data collection and analysis accelerate, threats multiply, but cryptography evolves along with them. Post-quantum algorithms, quantum cryptography, distributed protection systems – these are the future. Development will not stop.

Take care of your digital security. Use reliable tools, verify certificates, understand how the systems you use work. Cryptography works for you – from your browser to state systems. Being a conscious user means being a protected user.