Securing Digital Content: Cryptography and Data — Part 01

Cryptography is the art and science of encoding and decoding information and is foundational in securing digital communications and data. Cryptography transforms understandable information (plaintext) into a form that is incomprehensible (ciphertext). This process is known as encryption and it ensures that even if data falls into the wrong hands, its true meaning stays hidden. This post is the first in a series that are designed to cover the foundations of cryptography and its role in protecting data.

Understanding Data States

Using cryptography to safeguard data first requires an overview of the various states in which data can exist. Understanding these states — data at rest, in transit, and in use — is crucial for implementing effective encryption strategies as each state presents unique security challenges.

Data at Rest

Data at rest includes all information stored on physical or digital media, from hard drives and SSDs to cloud storage solutions and databases. This state of data is a prime target for attackers looking to exfiltrate sensitive information. Encryption helps to protect data at rest, transforming readable files into encoded ciphertext that require the correct key in order to be decrypted. Techniques such as AES (Advanced Encryption Standard), which are used to secure data against unauthorized access will be covered in the next part of this series.

Data in Transit

As data moves across networks — such as through emails, sharing files, or conducting online transactions — it enters a vulnerable state. Data in transit is susceptible to being intercepted by malicious actors focused on capturing sensitive information mid-transit. Encryption protocols like TLS (Transport Layer Security) maintain the confidentiality of data from sender to receiver. This encryption wraps the data in a secure envelope, making it unreadable without the decryption key, preserving privacy and security.

Data in Use

Perhaps the most challenging state to secure is data in use — data actively being processed or accessed by applications. This state requires that data be available in its unencrypted form for processing, presenting a potential security gap. Implementing obfuscation and encryption at the application layer are solutions for protecting data in use. These strategies ensure that data remains shielded from unauthorized access even in this vulnerable state.

Addressing the security needs of data in each of its states with appropriate encryption techniques reinforces overall resilience against cybersecurity threats. To understand how encryption provides a layer of security it is vital to explore the fundamental elements of cryptography.

Ciphers and Keys: Building blocks for Cryptography

A cipher is an algorithm that performs the encryption and decryption. These algorithms are mathematical functions designed to secure data. However, it’s important to note that the true strength of encryption lies not in the complexity of the algorithm but in the key used to unlock it.

Keys & Cryptographic Strength

The cryptographic key determines a cipher’s output. The key’s role in data security is underscored by the fact that an encryption’s efficacy is directly linked to the key’s length; generally, the longer the key, the stronger the security. Since the foundational encryption algorithms are well known and accessible, the focus of security must shift to management of the keys.

Due to its importance, periodically rotating and updating keys is considered a best practice in bolstering the encryption. Additional strategies include the storage of keys within secure hardware modules, encrypting keys when they are not in use, and ensuring secure transmission during use. Additionally, restricting key access to a select few as well as conducting consistent audits and oversight are critical measures for preserving the integrity of the encryption process.

Building on the importance of keys and cryptographic strength requires a deeper understanding of symmetric and asymmetric encryption methodologies, which represent the core mechanisms for securing data through cryptography. These methodologies differ primarily in their approach to key management.

Symmetric vs. Asymmetric Encryption

Symmetric encryption is characterized by its use of a single key for both the encryption and decryption of data. The benefit being efficiency and speed in scenarios requiring the handling of large data volumes. The structure of symmetric encryption implies the need for securely storing and periodically updating the singular key to maintain the integrity and strength of the encryption.

The ROT 13 cipher is a straightforward example of symmetric encryption, where a single key (in this case, the number 13) is used both to encrypt and decrypt information. Specifically, it encrypts text by shifting each letter 13 places forward in the alphabet. For example, ‘A’ becomes ’N’, ‘B’ becomes ‘O’, and so on. Because the English alphabet has 26 letters, applying ROT 13 twice returns the original text, making the same operation both encryption and decryption. This exemplifies symmetric encryption’s defining characteristic: the same key is employed for both processes.

While ROT 13 is simple and not secure enough for encrypting sensitive information — primarily because it’s easily reversible and does not vary the key, it is helpful for understanding encryption fundamentals. It demonstrates how an encryption key functions to transform readable data (plaintext) into a coded form (ciphertext) and back again, emphasizing the key’s central role in the cryptographic process.

Asymmetric encryption introduces a dual-key mechanism, consisting of a public key for encrypting data and a private key for decryption. This method has increased complexity and is important in securing digital communications by enabling only the intended recipient, who possesses the private key, to decrypt the message.

An example of asymmetric encryption in use today is the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) protocol used in HTTPS web connections. When you visit a secure website (indicated by HTTPS in the URL), your browser receives a public key from the website’s server as part of its SSL certificate. Your browser uses this public key to encrypt any information you send to the site, such as passwords, personal details, or credit card numbers. Only the server has the corresponding private key to decrypt the data you’ve sent. This ensures that even if someone intercepts the encrypted data while it’s in transit, they can’t decipher it without the private key.

Summarizing the Basics

The basics of cryptography are essential for securing digital information. Cryptography encodes information into a secure format, making it accessible only to those with the correct key, protecting data in its various states: at rest, in transit, and in use.

The basics of encryption and safeguarding data include the role of ciphers and keys as well as symmetric and asymmetric encryption. More complex aspects of cryptography, including algorithms and protocols designed to protect against cybersecurity threats are built on these foundational elements and are covered in the next post in this series.

Matthew Peterson is a seasoned professional with a Master’s degree in Global Management from Thunderbird School of Global Management and a graduate certificate from the Pacific Coast Banking School. Currently, Matthew is expanding his expertise by pursuing a Security+ certification, underscoring his commitment to continuous learning and excellence in his field.

You can connect with him on LinkedIn or by visiting his website.