Understanding data encryption to protect your sensitive information
Data encryption has become increasingly popular in recent years. The reason: an increase in the number of cyber-attacks, as well as data confidentiality issues.
But to exploit the full potential of this technology, we need to understand what it is and how it works in practice.
What is data encryption? What are the different existing systems, their advantages and their applications?
Here's how.
Data encryption: definition
In computing, data encryption is defined as the process of encrypting information to make it incomprehensible to unauthorised parties.
To do this, plaintext is transformed into ciphertext using an algorithm. Only an encryption key can be used to decrypt the content.
This technology can be used to protect :
- all types of data :
- strategic company data
- banking data
- personal information,
- passwords, etc.
- whether in transit on the web
- stored in the cloud
- or stored 'hard' :
- on a computer
- on a USB key
- external hard drive, etc.
As a result, data encryption is equally suited to private and professional use.
💡 Encryption or cryptography? It is customary for the two terms to be used interchangeably on the web. But purists will point out that this is a mistake. The word " encrypt" does not exist in computing. As for decryption, it applies to deciphering without possession of a key.
Why data encryption?
Cybersecurity issues
Identity theft, theft of bank details, hacking... data encryption helps protect you from ill-intentioned people.
Beware, however, that hackers use malice to attack the encryption itself, using :
- either a brute force attack: the hacker randomly tests all possible codes until he finds the right one ;
- a lateral attack: the hacker exploits flaws in the implementation of the encryption, rather than the encryption itself;
- or cryptanalysis: they try to deduce the encrypted message without having the encryption key in their possession.
Hence the importance of using long keys (which increase the number of possible combinations) and perfectly tested and mastered encryption systems.
Confidentiality issues
Data encryption is particularly popular with businesses because they store, handle and transfer a large amount of sensitive information.
By encrypting data, they can meet two major confidentiality challenges:
- strategic issues: business plans, customer files, manufacturing secrets... it would be detrimental if such information fell into the wrong hands.
- legal issues: certain professions, such as healthcare, are obliged to guarantee the confidentiality of the data in their possession.
Manchester Police was fined £120,000 in 2012 [...] for having an unencrypted USB stick stolen, containing the data of around 1,000 people linked to criminal investigations.
Source : CNIL
Other benefits of data encryption
Finally, it should be noted that some encryption systems also make it possible to :
- identify the origin of a message,
- certify the authenticity and integrity of the information it contains,
- guarantee non-repudiation: not to call into question the signature of a contract by the various parties, for example.
The different data encryption systems
The symmetric encryption algorithm
How it works
With this system, the same encryption key is used to encrypt and decrypt the message.
💡 Here's how it works:
- Ross generates a secret key.
- He then sends this secret key to Rachel securely.
- Ross encrypts his document using this same secret key.
- He then sends the encrypted document to Rachel.
- Rachel receives the document and decrypts it using the key she received earlier.
There are two types of symmetric encryption:
- Flow encryption: this operates bit by bit and uses an algorithm that operates continuously on the data. It is therefore particularly suitable for real-time communications.
- Block ciphering: each block of bits (64 for example) is transformed into encrypted blocks of the same size. This is the most widely used symmetrical encryption method.
Advantages and disadvantages
👍 Advantages:
Symmetric encryption requires faster calculation time. Practical if you have a large amount of data to protect.
It is also easier to understand for less experienced users.
👎 Disadvantages:
This type of encryption involves providing a key to the recipient, which can lead to security problems: one leak, and all the data is compromised. This is why this technology is best suited to :
- you want to encrypt documents for yourself,
- or if you are using a closed system.
Symmetric encryption, on the other hand, is mainly used to ensure data confidentiality, but does not go any further.
Examples of symmetric encryption algorithms
The most commonly used symmetrical encryption algorithms include :
- DES (Data Encryption Standard) encryption : a 64-bit block encryption system. The keys used are of the same size.
- AES (Advanced Encryption Standard) encryption : 128-bit block encryption. It uses keys of different sizes: 128, 192 or 256 bits.
- Blowfish: 64-bit block cipher. It requires keys of varying sizes, from 32 to 448 bits.
The asymmetric encryption algorithm
How it works
The asymmetric encryption algorithm uses two keys:
- a public key: this can be shared with anyone and is used to encrypt the data,
- a private key, to decode the message.
If they are "mathematically" linked, deducing the private key from the public key is impossible.
💡 Here's how it works in practice:
- Ross wants to send Rachel a message. So he asks her for her public key.
- Rachel sends her public key to Ross.
- Ross then encrypts his message using Rachel's public key.
- Ross then transfers the encrypted message to Rachel, who decrypts it using her private key.
Advantages and disadvantages
👍 Advantages:
The main advantage lies in the fact that the risks associated with transmitting decryption keys are avoided. In fact, if a malicious person intercepts the exchanges, it is the public key that is intercepted. It is then impossible to decrypt the message, as the private key has remained secure.
Asymmetric encryption also enables electronic signatures.
👎 Disadvantages:
This technique takes longer and is more complex than symmetrical encryption.
Examples of asymmetric encryption algorithms
The most commonly used asymmetric encryption algorithms include :
- RSA encryption (named after its founders Rivest, Shamir and Adleman): this is the most widely used asymmetric method, since it is based on the difficulty of factoring large integers.
- DSA (Digital Signature Algorithm) encryption: this algorithm was initially used to electronically sign documents.
How do you encrypt data? Examples of use cases and data encryption software
A wide variety of data can be encrypted, using a range of tools and software.
Here are a few examples to help you understand the different uses of data encryption.
Encrypting your communications
By e-mail
When it comes to e-mail communications, Gmail and Outlook users already have the option of encrypting their data:
- Gmail includes the S/MIME encryption standard in its solution, which is functional if both sender and recipient have activated it beforehand;
- Outlook can also be configured to integrate the S/MIME protocol into email exchanges.
💡 If you want stronger encryption, there are specialist mailboxes. ProtonMail, for example, has built its reputation on automatic end-to-end encryption. In other words, not even the provider can access your data.
By instant messaging
Some messaging applications also use end-to-end encryption, making data confidentiality one of their main selling points.
Signal is a case in point. Will this application replace WhatsApp, which is currently controversial for backing down on its user data encryption requirements?
Encrypting your passwords
The best way to guarantee the security of your passwords is to use a password manager equipped with encryption technology.
LastPass, for example, uses the AES 256-bit standard to encrypt and decrypt all your data locally. Everything is perfectly secure, since even the LastPass servers do not have access to your master password and encryption key.
Encrypting your documents
There are various algorithms for encrypting sensitive documents hosted on your computer or external hard drive. But as we saw earlier, the symmetrical method is still the most appropriate (no need to transmit a key).
Tools have been specially designed for this purpose. One of the most popular is 7-Zip. It is free and can be used to compress and encrypt files.
Encrypting your network
How can you encrypt your network to protect data circulating on the web? By using a VPN, a tool for connecting to the Internet in complete security, particularly on a public Wi-Fi network.
To do this, the VPN creates an encrypted tunnel through which your data travels to its provider's server. This server then decrypts your data and sends it back to the website or application you wish to visit.
Among the best-known players on the market is NordVPN and its AES 256-bit encryption standard.
You now have the keys to a better understanding of the challenges of data encryption.
Do you already use dedicated tools for this purpose in your company? Tell us about your experience in the comments ;-)
Article translated from French