Cryptography Guide: From Ancient Ciphers to Modern Blockchain Security

Have you ever wondered why your bank transfers are secure, social media chats are private, and shopping information is protected? The answer is cryptography — this mysterious and powerful discipline is safeguarding our entire digital world.

What exactly is cryptography

The simplest explanation: cryptography is the science of transforming information into a form that only authorized parties can read. But it’s much more than that.

The four pillars of cryptography

Cryptography has four core objectives:

Confidentiality — Ensuring that only authorized persons can read the information. This is key when you send bank transfers or private messages.

Data Integrity — Guaranteeing that information has not been tampered with during transmission or storage. Even a single digit change can be detected.

Authentication — Verifying that you truly are who you claim to be. Confirming that a transfer comes from you, not a scammer.

Non-repudiation — You cannot deny having sent a message or completed a transaction afterward. This is crucial for legal enforceability.

Real-world applications of cryptography

Ubiquitous in daily life

Seeing “https” and a padlock icon when opening your banking app? That’s TLS/SSL encryption working — it encrypts your login credentials, account information, and transaction data using cryptographic algorithms.

When using WhatsApp, Signal, or Telegram, your messages undergo end-to-end encryption — even the platform’s servers cannot see your content.

Accessing public Wi-Fi, though insecure, is protected by VPNs that create an encrypted tunnel using cryptography, preventing your traffic from being eavesdropped.

Cryptography in finance and blockchain

In the world of crypto assets, cryptography is the infrastructure. Blockchain systems like Bitcoin and Ethereum rely on the following cryptographic techniques:

• Cryptographic hash functions — Convert any data into a fixed-length “digital fingerprint.” Used in blockchain to link transactions and verify data integrity.
• Public key cryptography — Allows users to sign transactions with a private key, and the network verifies the signature with the public key, without trusting a third party.
• Digital signatures — Ensure that transactions are genuinely initiated by the holder of the private key and cannot be denied later.

Thanks to these cryptographic mechanisms, blockchains can operate without central banks, ensuring every transaction’s security and transparency.

Two main types of encryption

Symmetric vs Asymmetric encryption

Symmetric encryption uses one key for both encryption and decryption. It’s fast and efficient, suitable for encrypting large data (like entire databases or video streams). Common example: AES (Advanced Encryption Standard).

Disadvantage? The key must be securely shared beforehand. If intercepted, all protection is compromised.

Asymmetric encryption uses a pair of keys: a public key (known to everyone) and a private key (known only to you). Others encrypt data with your public key, and only your private key can decrypt it. This solves the “key distribution problem” of symmetric encryption.

Disadvantage? It’s much slower than symmetric encryption and not suitable for encrypting large files.

Practical approach: combine both. Use asymmetric encryption to securely exchange a symmetric key, then use that fast symmetric key to encrypt all data. HTTPS does exactly this.

Key cryptographic algorithms

DES and 3DES — early standards, now considered insecure.

AES (Advanced Encryption Standard) — the global standard. 128-bit keys, strong enough to resist brute-force attacks.

RSA — the most famous asymmetric algorithm, based on the difficulty of factoring large numbers. 2048-bit RSA keys are considered secure for decades to come.

ECC (Elliptic Curve Cryptography) — more efficient than RSA, achieving the same security with shorter keys. Increasingly adopted in modern systems, including Bitcoin.

Cryptographic hash functions — SHA-256 is the blockchain standard. It converts any input into a 256-bit hash, and even a tiny change in input completely changes the output (“avalanche effect”).

Evolution of cryptography

From ancient to modern times

Ancient Rome’s Caesar cipher was as simple as shifting letters by a fixed number. It’s worthless today but illustrates the basic idea of cryptography.

Vigenère cipher (16th century) used a keyword to determine multiple shifts, making it more complex. But it was cracked in the 19th century.

Enigma machine (Nazi Germany) was the pinnacle of mechanical encryption. It used rotating rotors and complex wiring, encrypting each character differently. British mathematician Alan Turing and Polish cryptanalysts eventually cracked it, reportedly shortening WWII.

Turning point in the computer age

The 1977 DES standard ushered in the era of computer encryption. Although its 56-bit key is now too short, it established the importance of cryptographic standardization.

In 1976, Diffie-Hellman introduced the revolutionary concept of “public key cryptography” — enabling secure communication without sharing secrets beforehand.

In 1977, the RSA algorithm realized this concept, becoming the foundation of e-commerce and modern network security.

In 2001, AES became the current global standard, expected to remain unchallenged for the foreseeable future.

Challenges of the post-quantum era

Quantum threats

Quantum computers can run Shor’s algorithm, which can break all current RSA and ECC encryption in a limited time. A sufficiently powerful quantum computer could do in hours what classical computers would take millions of years.

Solutions

Post-quantum cryptography (PQC) researches new algorithms resistant to quantum attacks. The US National Institute of Standards and Technology (NIST) is promoting new post-quantum standards.

Quantum Key Distribution (QKD) uses quantum mechanics principles: any eavesdropping attempt alters the quantum state and is immediately detected. While QKD itself isn’t encryption, it can securely distribute symmetric keys.

Global cryptography landscape

Russia’s stance

Russia has a long cryptography tradition rooted in Soviet mathematical schools. Today, Russia uses its own standards:

GOST R 34.12-2015 — symmetric encryption, including “Kuznechik” (128-bit) and “Magma” (64-bit).

GOST R 34.10-2012 — digital signatures based on elliptic curves.

GOST R 34.11-2012 (“Stribog”) — hash standard, outputting 256 or 512 bits.

The Federal Security Service (ФСБ) oversees licensing and certification of cryptographic tools. These standards are mandatory for government systems and organizations interacting with the government.

US and international standards

The US’s NIST sets de facto global standards. The National Security Agency (NSA) has historically participated in standard-setting, sometimes raising concerns about influence.

International organizations like ISO/IEC, IETF, and others coordinate global compatibility.

China’s independent path

China has developed its own cryptographic algorithms (SM2, SM3, SM4) and strictly monitors domestic cryptography use.

Moscow Cryptography Museum

Russia’s first and rare cryptography museum is located in Moscow.

It showcases ancient cipher machines, WWII Enigma, modern cryptographic hardware, and interactive exhibits explaining encryption principles. Visitors can try cracking codes and learn about quantum computing threats.

Address: Moscow, 25 Plantain Street. Check official website for opening hours.

Career prospects in cryptography

In-demand professional roles

Cryptographers — develop new algorithms, analyze their resistance. Require strong math background (number theory, algebra, complexity theory).

Cryptanalysts — specialize in cracking or assessing the security of encryption systems.

Information Security Engineers — implement cryptographic tools and protocols, manage PKI, monitor security threats.

Security Software Developers — correctly use cryptographic libraries and APIs in applications, avoid deployment errors.

Penetration Testers — find cryptography-related vulnerabilities in systems.

Core skills

Mathematical foundation (crucial), programming skills (Python, C++, Java), network and OS knowledge, analytical thinking, continuous learning habits.

Learning pathways

Top Russian universities: Moscow State University (Computer Science), Bauman Moscow State Technical University, Moscow Institute of Physics and Technology, etc., offer relevant programs.

Online platforms: Coursera, Stepik, “Open Education” provide beginner to advanced cryptography courses.

Career directions: IT companies, fintech (banks, payment systems, crypto exchanges), telecom, government agencies, defense industry, consulting firms.

High demand, high salaries, and continuous growth.

FAQs

What to do if I make a cryptography mistake?

“Cryptography error” messages often stem from certificate issues (expired), outdated software, or misconfigurations.

First, restart the program or system. Check certificate status and validity. Update cryptographic modules, browsers, and OS. Consult documentation or support. For digital signatures, contact the issuing certification authority.

What is a cryptography module?

A dedicated hardware or software component that performs cryptographic operations such as encryption, decryption, key generation, hashing, signing, and verification.

How can students get started?

Read popular science books like Simon Singh’s “The Code Book” or Schneier’s “Applied Cryptography.”

Solve puzzles on CryptoHack or participate in CTF competitions. Study math fundamentals (algebra, number theory, probability). Try coding simple ciphers (Caesar, Vigenère). Visit cryptography museums. Take online courses.

Summary

Cryptography is not an abstract academic topic; it’s the backbone of modern digital security. From protecting your private messages to ensuring blockchain transaction integrity, from financial systems to national security, cryptography is everywhere.

Understanding its principles and history helps you make smarter choices in the digital world. As quantum computing approaches, cryptography faces new challenges, but new solutions — post-quantum algorithms and quantum key distribution — are already in development.

In this digital age, the role of cryptography will only grow more important. Whether you’re a tech professional or an ordinary user, knowing about cryptography is a must for the future. Always choose platforms with strong security infrastructure to manage your digital assets — that’s the first step.