The interconnection between Cryptography and Computer Science is profound and intricate. As we navigate the digital world, the significance of cryptography in securing our digital interactions, safeguarding our privacy, and fortifying our systems is increasingly apparent.
Cryptography serves as the bedrock for secure communications, whether it’s your email exchange, WhatsApp conversation, or interaction on platforms like Instagram. This article unfolds the crucial role of cryptographic principles in the realm of computer science and how it anchors the security of our digital communications.
What is cryptography?
At its core, cryptography involves the crafting of protocols to ensure secure communication between a sender and receiver, shielding the information from unwanted eyes. Its origins lie in the Greek word ‘Kryptos,’ translating to ‘hidden.’ Intricately tied to the concept of encryption, cryptography involves the conversion of plain text into an encrypted form known as ciphertext and vice versa. It even extends to concealing information in images through techniques such as microdots or merging.
Cryptography’s most widespread application in digital data transmission is the encryption and decryption of emails and other text messages. The simplest form employs the symmetric or secret key system, where data gets encrypted using a secret key. Both the encrypted message and the secret key are then sent to the receiver for decryption.
However, the downside is that if a third party intercepts the message, they can decrypt and read it. To combat this, cryptologists developed the asymmetric or public key system, where each user has two keys: one public and one private. The sender requests the receiver’s public key, encrypts the message, and sends it. Only the receiver’s private key can decrypt the message, rendering theft futile without the corresponding private key.
Importance of Cryptography in Computer Science
Cryptography’s role in computer science and network security is escalating and will continue to do so. But why is Cryptography so crucial?
In the modern world, vast amounts of personal data get processed through cryptocurrencies, NFTs, blockchains, e-commerce, digital contracts, and digital signatures, all of which are susceptible to breaches. The relevance of cryptography becomes apparent when we consider that data breaches can lead to substantial financial losses.
People’s desire to keep their private data secure is another factor underlying the need for Cryptography in Network Security, as data falling into the wrong hands could have disastrous consequences.
One of the significant benefits of cryptography is its ability to maintain information confidentiality through unique keys and algorithms. Only individuals with these specific keys and requisite permissions can access the transmitted data.
Even in the event of a data breach, the data remains undecipherable unless the hacker possesses the necessary keys to unlock the encrypted data. This underlines the critical role of Cryptography in Network Security.
Another significant aspect to consider is the integrity of protected information and data. Through the use of hash algorithms and mathematical concepts, cryptography ensures the authenticity of the sender and receiver of the data.
Types of Cryptography in Information Security
The need for Cryptography in Network Security has led to the emergence of various types of Cryptography in information security, which can be broadly categorized into three types:
- Hash functions are algorithms that don’t need a unique key and calculate the value with fixed length as plain text. This makes the contents of the information behind a hash function impossible to retrieve and breach. Hash functions are often used for password encryption in various operating systems.
- Symmetric key cryptography is a type where the receiver and sender share a unique key used to encrypt and decrypt messages. While it is simple and fast for both parties, securely sharing the key can pose a challenge.
- Asymmetric key cryptography is the last of the general types of Cryptography in information security. This type of cryptography uses a set of two keys for encryption and decryption. The public key is used for encryption and the private key for decryption.
The importance of Cryptography in business is also becoming increasingly recognized due to its many advantages.
How is cryptography being used in computer science to deliver real life applications?
Blockchain
Blockchains employ two kinds of cryptographic algorithms, asymmetric-key algorithms, and hash functions. Hash functions provide a single view of the blockchain to every participant. Blockchains typically use the SHA-256 hashing algorithm as their hash function.
Cryptographic hash functions offer the following advantages to the blockchain:
- Avalanche effect – A slight alteration in the data can lead to a significantly different output.
- Uniqueness – Each input yields a unique output.
- Deterministic – The same input will always produce the same output when passed through the hash function.
- Speed – The output is generated in a very short time.
- Reverse engineering is impossible, i.e., we cannot generate the input by having the output and the hash function.
Verification/Digital Endorsements
Verification is any process that confirms or validates specific information. A digital endorsement is a cryptographic technique used to verify many of these aspects. A digital endorsement is data that’s derived from the document in question and the endorser’s private key. It is typically formulated using a hash function and a private endorsing function. These are algorithms that generate encrypted characters, containing distinct information about a document and its associated private keys.
Digital Time Stamping
Digital time marking is a process that verifies the existence or delivery of a particular electronic document or communication at a given time. This method utilizes a cryptographic model known as a blind signature scheme. These blind signature schemes allow the sender to have a message acknowledged by another party without exposing any details about the message itself.
Digital time marking is akin to sending a registered letter via mail, yet with an additional layer of confirmation. It can demonstrate that a recipient received a certain document. Possible uses extend to patent submissions, copyright repositories, and contracts. Digital time marking is a vital application that will expedite the shift towards electronic legal documentation.
Electronic/Digital Currency
Digital currency (also known as electronic cash or e-cash) is a developing concept. It encompasses transactions carried out electronically, resulting in the net transfer of funds between parties, which could either be a debit or credit transaction, and can be either anonymous or identified. There are both hardware and software-based implementations.
Unidentified applications shield the customer’s identity and are founded on blind signature schemes. Identified spending schemes disclose the customer’s identity and are built on broader forms of signature schemes. Unidentified schemes act as the digital counterpart of physical cash, while identified schemes are the digital equivalent of a debit or credit card. There also exist hybrid approaches where payments can be unidentified relative to the merchant but not to the bank or anonymous to all but still traceable.
In digital currency schemes, encryption is utilized to safeguard traditional transaction details like account numbers and transaction amounts, digital endorsements can take the place of handwritten signatures or credit card authorizations, and public-key encryption can ensure confidentiality.
Securing Email through Encryption/Decryption
Email encryption serves as a security measure that protects email content from outsiders who might be interested in accessing the information of participants in the email conversation. An email, once encrypted, becomes unintelligible to humans, and it can only be decrypted back into its original form using your private email key.
The mechanism employed in email encryption is known as public key cryptography. Every individual with an email address is assigned two keys linked to their address, which are necessary for the encryption and decryption of emails. One of these keys is the ‘public key’, which is accessible by anyone and stored on a keyserver linked to your name and email address. The other is the ‘private key’, which is kept secret and not shared with the public.
During the sending process, the email is encrypted by a computer using the public key, transforming the email content into a complex and nearly uncrackable scramble. This public key, however, can’t decrypt the sent message—it can only encrypt it. The power to decrypt the email and understand its contents lies only with the individual possessing the matching private key.
Email encryption exists in different forms, but standard protocols include OpenPGP—a decentralized, trust model-based encryption that’s compatible with contemporary web email clients—and S/MIME—an encryption built into most Apple devices that uses a centralized authority to select the encryption algorithm and key size. Email encryption services cater to encryption in several related areas:
- The connection between email providers can be encrypted to thwart external attacks from intercepting emails as they are transmitted between servers.
- Email content can be encrypted, ensuring that intercepted emails remain unreadable to the attacker.
- Stored or archived emails within your email client should also be encrypted to prevent potential access by attackers to emails not in transit between servers.
WhatsApp’s Encryption Protocol
WhatsApp employs the ‘signal’ protocol for encryption, which is a mix of asymmetric and symmetric key cryptographic algorithms. The symmetric key algorithms ensure confidentiality and integrity, while the asymmetric key cryptographic algorithms help accomplish other security objectives like authentication and non-repudiation.
In symmetric key cryptography, a single key is used for both data encryption and decryption. Conversely, asymmetric key cryptography utilizes two separate keys. A user’s data, when encrypted using their public key, can only be decrypted using their private key and vice versa.
WhatsApp’s chosen algorithm is based on Curve25519. This algorithm gained prominence following concerns about the potential manipulation of the P-256 NIST standards parameters by the NSA for easier surveillance.
Instagram’s Encryption
Your interactions with Instagram are likely secured through encryption. When your phone communicates with Instagram, it uses SSL/TLS over port 443 to secure requests from Instagram servers and receives data through the same encrypted stream. This measure prevents malicious entities from spying on the exchange between you and Instagram.
Conclusion
In essence, cryptography is the linchpin for a secure and trustworthy digital world, making it an indispensable part of computer science. As we continue to immerse ourselves deeper into the digital age, the importance of cryptography continues to escalate. It is through secure email exchanges, encrypted WhatsApp conversations, and SSL/TLS protected Instagram interactions that we get a glimpse of cryptography’s crucial role. As we stride forward, understanding and effectively using cryptographic systems will be pivotal to sustaining our digital safety and privacy.
