The Ultimate Guide to File Encryption Vs. Disk Encryption (2024)

When it comes to data security for sensitive data, encryption is one of very few methods that guarantees a robust protection under all circ*mstances. There are different encryption types, tools, and techniques for different data protection needs. Among them, File Encryption and Disk Encryption stand out as two of the most widely recognized and utilized data encryption techniques.

In this blog post, we'll delve into the definition of encryption, explore the key distinctions between file and disk encryption, examine their best use cases, and provide essential insights to help you determine which one is most suitable for your specific needs.

Encryption is a cryptographic process that transforms comprehensible and intelligible data into a scrambled and unreadable form called ciphertext. This is achieved by running the data through an encryption algorithm, like Advanced Encryption Standard (AES), which randomly rearranges and jumbles up the information, rendering it incomprehensible and unreadable after the process.

The process of rearranging and scrambling the data is done using complex mathematical algorithms using ‘cryptographic keys’ consisting of random and unique patterns of letters specifically associated with each encrypted file. Just like the unique keys for your house or car, which can only unlock the specified door of the house or car. The same mathematical calculations are also used for decryption, which reverses the encryption process to change back the data to the original form.

Let's consider a simple example to understand encryption better. Suppose you have a piece of text that says, “I like apples,” and you want to encrypt it. You can use a data encryption software like AxCrypt which uses AES 256-Bit encryption algorithm to convert the text into an encrypted form. The resulting encrypted text may look something like this: “v5u8/F28kOazjwQXTxY84+qeweiMvQ=.” As you can see, this encrypted text appears completely unreadable and incomprehensible, making it useless in the hands of a malicious attacker.

To get the original text from the encrypted version, you simply need to reverse the encryption process, which is referred to as decrypting. Decrypting takes the encrypted text and applies the decryption algorithm, using the appropriate key, to transform the ciphertext back into the original plain text. Just like opening your closed house or car door with a unique key. In this case, decrypting the encrypted text “v5u8/F28kOazjwQXTxY84+qeweiMvQ=” would yield the original text “I like apples” once again.

Encryption ensures that even if someone intercepts or gains unauthorized access to the encrypted text, they cannot understand its contents without the appropriate decryption process and key. This demonstrates how encryption safeguards sensitive information by converting it into a format that cannot be read and understood by anyone without the necessary decryption knowledge and key.

File encryption or file-based encryption (FBE), as the name suggests, is a method of encrypting files individually in a file system. It gives granular control over security measures as it allows for the encryption of individual files using a different key for each file. File-based encryption uses a robust encryption algorithm, such as the symmetric Advanced Encryption Standard (AES), to encrypt files and data.

To encrypt a file, the algorithm divides it into fixed-size blocks and then replaces and rearranges each block using the complex mathematical operations, including substitution (replacement of the text), permutation (rearrangement of the text), and bitwise operations (logical procedure), to obfuscate the original data.

For instance, in the case of the text “I Like Apples,” the algorithm substitutes each letter with a randomized corresponding value, arbitrarily permutes the order of the characters, and applies bitwise operations. The encrypted result will be a transformed ciphertext. Here's how it works:

Substitution: 'I' becomes '83', 'L' becomes '=x', 'i' becomes '45', and so on.

Permutation: The order of the characters is rearranged based on mathematical transformations. ‘83’ and ‘=x’ will be rearranged in the order and might appear after ‘45’ as ‘4583=x.’

Bitwise Operations: XOR and bit shifting operations are applied to alter the bit patterns (arrangement) of the data.

This process is further repeated for each letter of the text for multiple ‘rounds’, depending upon the round key size. The AES algorithm comes with 10, 12, and 14 round key sizes. So after applying the 14 round key to the text “I Like Apples,”, the resultant text by the end of the process may look like this: “v5C2uD8FE27A8F5/1B2F9k0AD3zQw8QXTxY6C7D4F8+E6kC2D7F4i91M6v2e9Qi9AbB3” – a completely unintelligible string of characters.

The whole process typically involves generating a session key, which is then securely shared along with the file during the transmission of data for decryption. The key holds the mathematical model to encrypt and decrypt the specific file for that specific session, ensuring only people who have access to this key can decrypt the data. File-based encryption provides a high level of security by ensuring that sensitive information remains protected both at rest and in transit.

Disk encryption or full disk encryption (FDE), as the name suggests is a method in which the entire disk gets encrypted. It differs from file encryption in the aspect that instead of individual files, the whole disk is encrypted and decrypted at once, including the operating system and related files.

Think of full disk encryption as locking your entire house with the main door, and file encryption as locking individual safes inside your house. You encrypt disks using a disk encryption software such as Microsoft BitLocker or Apple’s FileVault.

Similar to the file encryption, the full disk encryption process operates at the block level, dividing the disk into fixed-size blocks and encrypting each block using a symmetric encryption algorithm such as Advanced Encryption Standard (AES). This ensures that all data on the disk is transformed into an unreadable form that can only be deciphered with the appropriate decryption key.

The encryption key used in disk encryption is typically derived from a user password or passphrase. When the system boots up, the user is prompted to provide the password or passphrase to unlock the disk. Once authenticated, the encryption key is decrypted and used to access the encrypted disk contents.

During the encryption process, the algorithm works in a cascading manner, encrypting each disk sector with the derived key. This process continues until the entire disk is encrypted. The encrypted data is stored in a way that preserves the disk structure, allowing the operating system and applications to access the data seamlessly.

Each encryption type has its features and while deciding on a data encryption method, it's important to understand how file encryption and full disk encryption differ. Knowing these differences can help you choose the right approach for your encryption needs. Let's look at the key ways these two encryption methods distinguish:

Each of these differences and features such as principle, speed, security, affordability etc. can be weighed while making a choice between file and disk encryption for your specific data security needs.

When choosing between file encryption and disk encryption, consider your data security needs. File encryption provides granular control by encrypting individual files with unique keys, offering enhanced security and faster processing for selective access. Disk encryption encrypts the entire disk with a single key, providing convenience but potentially slower performance. File encryption offers higher security as each file has its own encryption key, while disk encryption relies on a single key for the entire disk.

File encryption is generally more affordable and allows for easier data recovery in case of file loss or key issues. It also enables selective access to encrypted files. In contrast, disk encryption may require additional software or hardware, and data recovery can be challenging if encryption keys are lost or the disk fails.

Ultimately, consider factors such as security, affordability, data recovery, accessibility, and ease-of-use to make an informed decision based on your specific requirements. File encryption is ideal for granular control and faster processing, while disk encryption offers the convenience of encrypting the entire disk.