Abu Zar Mishwani
Cryptography refers to the practice of securing sensitive data and communications by converting them into an unreadable format using codes. This process ensures that only authorized individuals can access and decipher the information.
In Computer Science, cryptography is a technique that uses mathematical algorithms to secure information and communication. It transforms messages using rule-based calculations, making them difficult to understand without proper decryption.
Deterministic algorithms are employed in various cryptographic processes, such as cryptographic key generation, digital signing, and verification. This technique is utilized to ensure data privacy in web browsing and confidential communications like credit card transactions and email.
Different Cryptography Techniques
Cryptography is interconnected with the fields of cryptology and cryptanalysis. It encompasses a wide range of techniques, including microdots, concealing information in images, and other methods for hiding information during storage or communication.
In the present computer-focused era, cryptography is mainly associated with the process of encrypting plaintext, which is ordinary text, into ciphertext, and then decrypting it back again. Cryptographers are the individuals who specialize in this field.
Modern cryptography is concerned with achieving the following four objectives:
- Confidentiality: This objective is all about protecting information from being accessed by unauthorized individuals. Confidentiality means that only those who are authorized to access the information can view or read it. Cryptography is used to transform information into an unreadable format so that it is kept confidential, even if it falls into the wrong hands.
- Integrity: Integrity is the assurance that information has not been tampered with, modified, or altered in any way. Cryptography is used to create digital signatures, which can verify that a message or data has not been changed from its original form.
- Non-repudiation: Non-repudiation refers to the ability to prove that a message or transaction was sent or received by a particular individual and that they cannot deny it later. Cryptography is used to provide proof of the sender and receiver’s identity, as well as the authenticity of the message or transaction.
- Authentication: Authentication is the process of verifying the identity of the person or entity attempting to access a system or service. Cryptography is used to generate digital certificates, which are used to verify the identity of the user and ensure that they are who they claim to be.
Cryptosystems refer to the procedures and protocols that meet one or more of the above objectives of modern cryptography. While cryptosystems are often associated with mathematical algorithms and computer programs, they also involve regulating human behavior to ensure maximum security.
Some examples of human behavior that contribute to a secure cryptosystem include selecting strong passwords, logging off unused systems, and refraining from discussing sensitive procedures with individuals outside of authorized personnel.
These measures help to prevent unauthorized access and protect confidential information.
Understanding Cryptographic Algorithms
Cryptosystems utilize a collection of procedures called cryptographic algorithms or ciphers to secure communications between computer systems, devices, and applications. These algorithms enable the encryption and decryption of messages, ensuring that sensitive information remains confidential and secure during transmission or storage.
Cipher suites involve the use of different cryptographic algorithms to ensure secure communication between computer systems.
This process uses a combination of protocols and software, which includes public and private key generation for data encryption and decryption, digital signing and verification for message authentication, and key exchange.
Cipher suites are essential to ensure secure communication between networked computer systems by using different algorithms for different tasks, ensuring the confidentiality and integrity of the data being transmitted.
Types of Cryptography
Cryptography can be broadly classified into two main types:
- Symmetric Key Cryptography
- Asymmetric Key Cryptography
Symmetric Key Cryptography
This type of cryptography involves the use of a single secret key for both encryption and decryption of messages. The sender and receiver share this secret key, and the encryption and decryption processes are performed using this key.
A commonly used example of symmetric key cryptography is the Advanced Encryption Standard (AES), which is used to encrypt data at rest or in transit.
Asymmetric Key Cryptography
In this type of cryptography, two different keys are used for encryption and decryption. One key is called the public key, which is shared with anyone who wants to send a message to the receiver. The other key is called the private key, which is kept secret by the receiver.
The sender encrypts the message using the receiver’s public key, and only the receiver can decrypt the message using their private key.
A commonly used example of asymmetric key cryptography is the RSA algorithm, which is used in secure email communication and secure web browsing.
To ensure that the data is not tampered with during transmission, cryptographic hash functions are employed. Hash functions produce a consistent output value for a given input value, and the output value is of a fixed size. Examples of cryptographic hash functions are SHA-1, SHA-2, and SHA-3.
History of Cryptography
The term “cryptography” comes from the Greek word “kryptos,” which means hidden. The prefix “crypt-” signifies something that is hidden or secret, while the suffix “-graphy” refers to the art or practice of writing.
Cryptography’s beginnings can be traced back to around 2000 B.C. when the ancient Egyptians used hieroglyphics for communication. These hieroglyphs were intricate symbols that only a select few could interpret and understand the full meaning of.
Julius Caesar is credited with using the first modern cipher around 2,000 years ago. He developed this system as a way to protect the messages he sent to his officers and governors because he did not trust his messengers.
The system involved replacing each character in his messages with another character three positions ahead of it in the Roman alphabet. This method is now known as the Caesar cipher.
Cryptography has become a highly contested field in modern times, with top mathematicians and computer scientists competing to develop the most secure encryption techniques. The ability to protect sensitive information has become increasingly important for both military and commercial success.
Governments often seek to prevent unauthorized access to sensitive information that could threaten national security. As a result, cryptography has faced many restrictions in several countries. These restrictions vary from limiting the use and export of cryptographic software to prohibiting the public disclosure of mathematical concepts that could be used to develop cryptosystems.
While cryptography has faced restrictions in many countries due to concerns over national security, the widespread use of the internet has led to the dissemination of powerful cryptographic programs and techniques. As a result, some of the most advanced cryptosystems and ideas are now available to the public.