What is Cryptography : Definition, Types, and Benefits

What is Cryptography? Cryptography is the study of techniques for securing information by ensuring its confidentiality, integrity, and validity.

In today’s digital era, exchanging messages via email, chat, and SMS platforms is a common form of communication for sharing information. The use of various applications is considered more convenient in any situation and location. The activity of exchanging messages through chatting requires a continuous internet connection to ensure that messages are delivered to their intended recipients.

Did you know that a security system is necessary to guarantee the confidentiality of the information we send? Its function is to maintain access rights, ensuring that only authorized individuals can view the contents of our messages. One of the information security systems that can protect message exchanges in the form of chatting is called cryptography. Let’s take a closer look at the definition, history, purpose, and types of cryptography.

What is Cryptography

What is Cryptography ? Cryptography comes from the Greek words kryptos, meaning “hidden,” and graphein, meaning “writing.” Cryptography is the study of techniques used to secure information, including maintaining data confidentiality, integrity, and validity. However, it is important to note that not all information is secured using cryptography. Cryptography is often likened to the art of exchanging information securely while ensuring that access rights are strictly maintained.

Cryptography is not only about hiding messages but also ensuring that the message maintains integrity (data integrity) so that it reaches the recipient intact and correctly from a legitimate source (authentication). In this digital era, where almost all aspects of our lives are connected to the internet, data security is becoming increasingly crucial and important. A vast amount of personal data, ranging from financial information to sensitive data, is stored online. Without a cryptographic system, this data could easily be stolen, altered, or misused by various irresponsible parties.

Cryptography History

Cryptography has a long history, dating back to ancient Egyptian civilization, where people used traditional methods to conceal messages, such as secret hieroglyphs. Julius Caesar, the Roman emperor, was famous for using the Caesar cipher, in which each letter was shifted several positions forward in the alphabet.

Over the centuries, cryptographic techniques have continued to evolve. The Enigma machine, used by Nazi Germany during World War II, was an example of complex cryptography for its time. However, with advancements in mathematics and computer science, the Enigma machine was eventually cracked by the Allies.

Mathematics plays a role in concealing messages using complex algorithms, where the same key is used for encryption and decryption. Similarly, computer science contributes to analyzing and testing the security of cryptographic algorithms to ensure resilience against data theft attacks.

Cryptography Purpose

Cryptography serves several key purposes in enhancing information security:

Confidentiality

The purpose of cryptography is to ensure that only authorized parties can access information, such as email messages. The encryption process ensures that only recipients with the decryption key can read the message.

Example: Some chat applications use cryptography to protect message contents so they cannot be read by anyone other than the authorized sender and recipient.

Data Integrity

Cryptography ensures that information is not altered or tampered with during transmission or storage, guaranteeing that data reaches the recipient in its original, unmodified state.

Example: Digital signatures can be used to verify data integrity. Digital signatures are a crucial cryptographic application that not only authenticate the source of information but also maintain data integrity.

Authentication

Cryptography ensures the authentication of information sources. Digital certificates, a key component of cryptography, play a significant role in verifying the authenticity of an information source. A digital certificate is an electronic document that binds the identity of the public key owner with a trusted Certification Authority (CA). The CA is responsible for verifying the identity of the public key owner before issuing a digital certificate. Information contained in a digital certificate, such as name, email address, and validity period, can be used to verify the identity of a message or electronic document sender.

Example: When shopping online, digital certificates are used to verify the authenticity of an e-commerce website and ensure the security of payment information.

Non-Repudiation

Cryptography prevents unauthorized parties from denying the sending or signing of information. Digital signatures also help ensure non-repudiation.

Example: A digital signature on an electronic contract ensures that neither party can deny having signed the contract at a later date.

Also Read : What is IP Address

Types of Cryptography

In general, cryptography is divided into two types: Symmetric Cryptography and Asymmetric Cryptography.

Symmetric Cryptography uses the same secret key for both encryption (scrambling) and decryption (deciphering) of messages. An example of this is the DES (Data Encryption Standard) algorithm, which was widely used in the past.

Encryption is the process of converting plaintext (understandable text) into an unreadable code (ciphertext). The reverse process is called decryption, which converts ciphertext back into plaintext. Cryptography is thus the science of encryption and decryption techniques to make information unreadable to unauthorized parties.

In practice, the encryption and decryption processes often use classical cryptographic algorithms. Classical cryptographic algorithms typically rely on character manipulation and symmetric keys. One common classical algorithm is the Caesar cipher, which employs a simple substitution technique to shift each letter in the alphabet by a specific number of positions. However, classical algorithms generally have a weakness: they are vulnerable to brute-force attacks, where all possible keys are tested one by one.

Asymmetric Cryptography, on the other hand, uses two different keys: a public key and a private key. The public key can be freely shared, while the private key is kept secret. Messages encrypted with the public key can only be decrypted with the corresponding private key.

Asymmetric cryptography is generally recognized as a modern cryptographic system. It is considered more secure than symmetric cryptography because it eliminates the need for secure secret key distribution. One well-known asymmetric cryptographic algorithm is RSA (Rivest–Shamir–Adleman). The advantage of asymmetric cryptography is its strong security, as it relies on complex mathematical and computational algorithms.

Also Read : What is Artificial Intelligence

Cryptography Techniques

Cryptography employs various mathematical techniques to secure information. Some commonly used techniques include:

Substitution: A classical encryption method that replaces characters in a message with other characters based on a specific rule. The Caesar cipher is a simple example of substitution.
Transposition: A technique that rearranges the characters in a message to make it unreadable to those without the encryption key.
Block Encryption: A method that divides a message into fixed-size blocks and encrypts each block using a specific algorithm.
Stream Encryption: A technique that encrypts messages bit by bit in a sequential manner.
Hashing: A process that converts digital data (such as text, images, or files) into a fixed-length unique string called a hash value or digest. Hashing is commonly used to verify data integrity.

Modern Cryptography

Advancements in computer science have revolutionized cryptography. Complex cryptographic algorithms can now be developed and implemented more efficiently. Modern cryptography is based on sophisticated mathematical and computational principles, and cryptographic standards today undergo rigorous testing to ensure their security and reliability.

Examples of modern cryptographic applications in daily life include:

Online Shopping: Credit card information is encrypted to prevent data theft.
Online Banking: Cryptography secures connections, protects login credentials, and safeguards transactions with digital signatures.
Email Communication: Email content is encrypted to prevent unauthorized access.
VPN Connections: Cryptography encrypts data transmitted over public internet networks.

Conclusion

Cryptography is an essential security technique in the digital era. By understanding cryptographic concepts and techniques, we can protect our personal data and online activities from various security threats.

Join us at Private University in Surabaya to study cryptography in depth, exploring the latest techniques in information security.

References

Amin, M. (2016). IMPLEMENTASI KRIPTOGRAFI KLASIK PADA KOMUNIKASI BERBASIS TEKS. Jurnal Pseudocode, Volume III Nomor 2, 129-136.

Author : Meilina Eka Ayuningtyas

What is Cryptography : Definition, Types, and Benefits

What is Cryptography

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