Cryptography and Digital Security: From History to Modern Technologies

Why Cryptography Is Necessary for Everyone

When you send a message to a friend via messenger or make a payment in an online store, everything is secure thanks to cryptography. It is an invisible but critical technology that protects your privacy, financial data, and confidential information from unauthorized access. In the digital world, cryptography is the foundation of everything, from secure web banking to the functioning of modern blockchains and cryptocurrencies.

What Is Cryptography: Basic Concepts

Cryptography is a comprehensive science about data protection through transformation. The word originates from ancient Greek: κρυπτός (hidden) + γράφω (write). But it is not just encryption – it encompasses a much broader range of security methods.

Main Tasks of Cryptography

1. Confidentiality – ensuring that only authorized persons can read the information
2. Data Integrity – guaranteeing that data has not been altered or damaged during transmission
3. Authentication – verifying the authenticity of the message source or user
4. Non-repudiation – the sender cannot deny having sent the message

A simple example: if you want to send a secret message to a friend, you can replace each letter with the next one in the alphabet. This is elementary cryptography, but in the modern world, algorithms are much more complex.

Where Cryptography Is Used Daily

• HTTPS in browsers – the padlock icon next to the website address indicates that the connection is encrypted
• Messengers – Signal, WhatsApp, and other apps encrypt your correspondence
• Wi-Fi networks – protocols WPA2/WPA3 protect home internet
• Bank cards – EMV chip performs cryptographic authentication
• Online payments – all internet transactions are protected by encryption
• Electronic signatures – confirm the authenticity of digital documents
• Blockchain and cryptocurrencies – use cryptographic hash functions and digital signatures

Difference Between Cryptography and Encryption

These terms are often confused, but they are not synonyms:

Encryption – is the process of converting readable text into an unreadable format using an algorithm and a key.

Cryptography – is the science that includes:

• Development and analysis of encryption algorithms
• Cryptanalysis (methods of decryption)
• Development of secure protocols
• Key management
• Hash functions and digital signatures

Thus, encryption is just one tool of cryptography.

History of Cryptography: From Ancient Times to Today

Ancient Times

The earliest examples of encryption appeared in Ancient Egypt around 1900 BC, where scribes used non-standard hieroglyphs. In Ancient Sparta (5th century BC), they used scytale – a wooden staff around which paper was wrapped. The message was written along the staff, and only by unwinding the strip on a staff of the same diameter could the text be read.

Classical Ciphers

Caesar Cipher (1st century BC) – one of the most famous. It worked on a simple principle: each letter was replaced with the letter a few positions later in the alphabet. It was easily decrypted by brute-force methods.

Vigenère Cipher (16th century) was much more complex. It used a keyword to determine the shift for each letter. For a long time considered unbreakable, it was cracked in the 19th century.

Machine Era

During World War I, cryptography became a strategic asset. Breaking the German Zimmerman telegram significantly contributed to the US entering the war.

World War II was the golden age of mechanical cryptography. The German Enigma machine created extremely complex ciphers that changed with each letter. Its decryption by British and Polish mathematicians, including Alan Turing, was crucial to the war effort.

Computer Revolution

In 1949, Claude Shannon published the foundational work “A Mathematical Theory of Communication of Secrecy Systems,” which laid the mathematical groundwork for modern cryptography.

In the 1970s, DES (Data Encryption Standard) appeared – the first widely recognized standard for computer encryption.

In 1976, Whitfield Diffie and Martin Hellman proposed a revolutionary concept – public key cryptography. This allowed secure key exchange without prior agreement. Soon, the RSA algorithm was developed, which remains relevant today.

Modern Cryptographic Algorithms

Symmetric and Asymmetric Cryptography

Symmetric cryptography: the same key is used for encryption and decryption. Analogy – a regular lock with a key.

Advantages: high speed
Disadvantages: need to securely transmit the key

Examples: AES, DES, Blowfish

Asymmetric cryptography: uses two mathematically related keys – public and private. Analogy – a mailbox: anyone can deposit a letter (encrypt), but only the owner with the key can access the contents (decrypt).

Advantages: solves the key distribution problem, enables digital signatures
Disadvantages: significantly slower than symmetric

Examples: RSA, ECC (Elliptic Curve Cryptography)

Hybrid Approach

In practice, both methods are combined: asymmetric cryptography is used for secure key exchange, then fast symmetric cryptography encrypts the main data volume. That’s how HTTPS works.

Cryptographic Hash Functions

Hash functions transform data of arbitrary length into a fixed-length string – a “digital fingerprint.” Main properties:

• Pre-image resistance: impossible to recover original data from the hash
• Deterministic: the same data always produces the same hash
• Collision resistance: practically impossible to find two different data sets with the same hash
• Avalanche effect: minimal change in data completely changes the hash

Examples: SHA-256, SHA-512, SHA-3

Russian Encryption Standards (GOST)

Russia has developed its own cryptographic standards:

• GOST R 34.12-2015: for symmetric encryption (algorithms “Kuznechik” and “Magma”)
• GOST R 34.10-2012: for digital signatures based on elliptic curves
• GOST R 34.11-2012: hash algorithm “Streebog”

Use of GOST standards is mandatory when working with government systems and information in Russia.

Cryptography in Modern Applications

Internet Security

TLS/SSL protocols provide secure web traffic. The padlock icon in the browser indicates:

• Server authentication
• Establishment of a secure channel
• Encryption of all traffic between browser and server

End-to-end encryption (E2EE) is used in secure messengers. Messages are encrypted on the sender’s device and decrypted only on the recipient’s device. Even the messenger operator cannot read the content.

Banking Security

• Online banking: protected via TLS/SSL, two-factor authentication, database encryption
• EMV cards: cryptographic chip authenticates the card with the terminal
• ATMs: encrypt communication with processing centers, protect PIN codes

Digital Signatures and Document Workflow

Electronic signatures confirm authorship and integrity of documents:

1. Create a hash of the document
2. Encrypt the hash with the sender’s private key
3. Recipient decrypts the hash with the public key
4. If hashes match – the document is authentic

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

Cryptography and Blockchain

Blockchain assets use cryptographic hash functions and digital signatures:

• Each block is linked to the previous via hash
• Transactions in cryptocurrencies are signed with digital signatures
• Wallet addresses are generated using cryptographic functions

Corporate Security

• Encryption of confidential databases and archives
• VPNs for secure remote access
• Encryption of corporate email
• Access management via cryptographic tokens

Quantum Computers and the Future of Cryptography

The emergence of powerful quantum computers poses a threat to most modern asymmetric algorithms (RSA, ECC). Shor’s algorithm run on a quantum computer can break them relatively quickly.

Post-Quantum Cryptography (PQC)

New algorithms are being developed that will be resistant to both classical and quantum computers. They are based on other complex mathematical problems:

• Lattices
• Codes
• Hashes
• Multidimensional equations

The standardization process for post-quantum algorithms is actively ongoing by the global cryptographic community.

Quantum Cryptography

Uses principles of quantum mechanics to protect information. Quantum key distribution (QKD) allows creating a shared key securely, with any interception attempt immediately detected through changes in quantum states.

Cryptography and Steganography

These are two different approaches to hiding information:

Cryptography: conceals the content of the message. The text is encrypted and unreadable without the key.

Steganography: conceals the very existence of a secret message. The text can be hidden inside an image, audio, or video so that no one knows about its presence.

They are often used together: first encrypt the message with cryptography, then hide it with steganography.

The Role of Cryptography in Different Countries

International Standards

• NIST (USA): develops global standards (DES, AES, SHA series)
• ISO/IEC: international standards for information security
• IETF: standards for the Internet (TLS, IPsec)

National Approaches

Different countries develop their own expertise and standards, but common trends and international cooperation ensure global compatibility and reliability.

Careers in Cryptography and Cybersecurity

In-demand Professions

Cryptography researcher: develops new algorithms and protocols, analyzes cryptographic resilience. Requires deep mathematical knowledge.

Crypto analyst: analyzes and tests cryptosystems for vulnerabilities.

Information security engineer: implements cryptographic solutions in practice, configures security systems.

Secure software developer: uses cryptographic libraries in application development.

Penetration tester: tests systems for vulnerabilities, including improper use of cryptography.

Necessary Skills

• Mathematics (number theory, algebra)
• Programming (Python, C++, Java)
• Network technologies and protocols
• Analytical thinking
• Continuous self-education (the field is rapidly evolving)

Where to Learn

• Leading universities have programs in cryptography and cybersecurity
• Online platforms offer courses from universities and experts
• Cryptography competitions (CTF) help develop practical skills
• Books and scientific publications for in-depth understanding

Prospects

The demand for cryptography and cybersecurity specialists is constantly growing. Salary levels are higher than the average in the IT market, especially for experienced professionals with deep knowledge. It is a dynamic field offering intellectual challenges and good career prospects.

Frequently Asked Questions

What to do if a cryptographic error occurs?

Cryptographic errors can occur when working with electronic signatures, certificates, or cryptographic hardware:

1. Restart the program or computer
2. Check the validity and status of the certificate
3. Update cryptographic hardware and browser
4. Verify settings according to instructions
5. Try a different browser
6. Contact technical support

What is a cryptographic module?

It is a hardware or software component designed to perform cryptographic operations: encryption, decryption, key generation, hash calculation, creation and verification of electronic signatures.

How to study cryptography independently?

• Study the history of simple ciphers (Caesar, Vigenère)
• Solve cryptographic tasks on specialized platforms
• Read popular science literature
• Study mathematics (algebra, number theory)
• Implement simple ciphers in programming languages
• Participate in online courses and competitions

Conclusion

Cryptography is not just a set of mathematical formulas but the foundation of digital security. From protecting personal correspondence to the functioning of blockchain and cryptocurrencies, its role is continuously growing.

Understanding the basics of cryptography is important not only for cybersecurity professionals but for any user of digital services. With new challenges like quantum computers, cryptography continues to evolve, developing new solutions to ensure the security of our digital future.

Take care of your digital security, use reliable protection tools, and choose trusted platforms for your online activities.