To put it simply, cryptography can be referred to as both an art and a science that encrypts messages into an illegible version known as ciphertext, protecting the information from being accessed by unauthorized people. Only a person with the right key can then convert it back to its original version, which is known as plain text. As communication through digital means becomes more common, more so to the general public, so does the need for cryptography in protecting the information from access, abuse, and secrecy.

Key Concepts in Cryptography

Before analyzing the specific types and approaches to cryptography, there are some basic details that one must acknowledge: 

Plaintext: The content and information in question within a text that is intelligible. 
Ciphertext: The enciphered version of the plaintext that is encoded and requires a key for interpretation. 
Encryption: The conversion of an intelligible message into an unreadable message (ciphertext) using an algorithm and a key, inviting the possibility of decoding the original message in the future. 
Decryption: This is the process that is undertaken when one wants to reveal cite a particularly coded message—the message in question has already been manipulated and taken to a scribe and therefore needs some sort of transformation for it to be decodable. 
Key: A key is defined as a factor that affects the operation of a cryptography system. This could be a code, set of characters, or an image.

Types of Cryptography

Cryptography can be broadly categorized into three main types:

1. Cryptography with a symmetric key: In this case, an identical key is employed for both encoding and decoding processes. This technique is also cost-effective and quick, thereby allowing the encryption of larger volumes of data without much stress. Nevertheless, the key would have to be kept secret and safe from the other parties involved in the communication. An example of such a cryptologic method would be the Advanced Encryption Standard, AES.
2. Asymmetric Cryptography: Commonly referred to as public-key cryptography, this approach employs a dual-key mechanism in which a public key is employed for encrypting and a corresponding private key is utilized for performing decryption. While the public key is acceptable to be distributed, the private key should always be kept a secret. The exchange of keys in asymmetric cryptography offers increased protection, and this is the reason why SSL or TLS are used for safe surfing applications. An example of an asymmetric encryption standard is RSA, which stands for Rivest Shamir Adleman algorithm.
3. Hash Functions: Although they do not constitute a method of secret writing, hash functions take the input data and produce a string of characters of a fixed size, which is in appearance random. Common applications of hashes include checking for data integrity and user password management since these are functions that can only work in one direction.

Basic encryption techniques

A few basic encryption techniques are usually the starting point in comprehending the concepts of cryptography:

Caesar Cipher: The Caesar cipher is one of the oldest and very easy-to-use encryption techniques. It provides a simple fixed shift of the alphabet letters. For example, if the shift is 3, then A changes to D, B changes to E, and so on.

Substitution Cipher: In this technique, all instances of a letter in the text when applying encryption are replaced with some other (for example, “B” becomes “Z” and vice versa). The key must be known to both parties in order to use the tool, aka the substitution rule.

Transposition Cipher: A plain text is broken into several parts, and the parts are arranged in proper order according to some defined method. Unlike in substitution, letters are not replaced but changed in their order only in this method.

Modern Cryptography

The evolution in cryptography has brought in a new era that embeds using complex algorithms and high-tech methods in protecting information. Some of the most used contemporary cryptographic techniques comprise the following:

AES (Advanced Encryption Standard): A symmetric key encryption algorithm that works on a block of data and whose main aim is to protect sensitive data
Advanced Encryption Standard: The common asymmetric algorithm for encrypting, signing, and sending non-public data over the communication channels
ECC (Elliptic Curve Cryptography): Another asymmetric encryption scheme that provides the same security as RSA (Rivest Shamir Adleman) systems but has a shorter key size, which enhances efficiency.

Applications of Cryptography

Cryptography finds usage in numerous sectors for the purpose of protecting data and ensuring its confidentiality, including but not limited to:

Safe Communication: This is incorporated into chat and email applications to prevent the leakage of users’ conversations.
E Commerce: Guarantees that there are no losses incurred while making purchases online by securing an individual’s credit card details.
Digital signatures: allow for the verification of the authorship and the correctness of the content of electronic documents and programs.
VPN (Virtual Private Network): Ensures the safety of all the online activities performed by a user by encoding their internet traffic.

Challenges in Cryptography

Cryptography is essential but it can also present many problems, such as:

Key Management: The safe storage and sharing of the cryptographic keys in a large organization remains the biggest challenge.
Quantum Computing: As more advanced quantum computers are developed, a number of existing forms of encryption will be compromised by the developments.
Regulatory Compliance: Issues with the implementation of cryptography may arise due to the need to comply with several laws and policies on data security and privacy.

Conclusion

The study and practice of cryptography is an indelible part of contemporary security measures and more so in safeguarding personal and confidential data in the digital age. Knowledge of its elementary concepts and procedures lets one appreciate how an individual or institution can secure its data over the internet.

FAQs

Is it possible to compromise encoded information?

Encryption helps secure information; however, no system can defend against intrusion. Encrypted data hacking is many times more difficult because of strong encryption algorithms.

What is a digital signature?

A digital signature is a means that helps to ensure the origin and the integrity of the electronic document or message.