What is encryption?

Encryption: definition and purpose

In encryption (cryptography), readable data, the plaintext, is converted into ciphertext using a mathematical method and a key. Without the matching key, it is practically worthless. The method protects confidentiality; combined with signatures and checksums, it also ensures that data has not been changed unnoticed.

What matters are proven methods and the keys, not keeping the algorithm secret. Publicly reviewed methods such as AES are considered secure when used correctly, whereas home-grown solutions are error-prone. The GDPR explicitly names encryption as an example of suitable technical safeguards.

Symmetric, asymmetric and where it is used

Symmetric methods such as AES use the same key to encrypt and decrypt and are fast—ideal for large amounts of data. Asymmetric methods such as RSA or elliptic-curve methods work with a key pair of public and private key; they solve secure key exchange and enable digital signatures. In practice, both are combined, for example in TLS.

• In transit: TLS/HTTPS for websites, encrypted email delivery, VPN
• At rest: disk encryption such as BitLocker, encrypted databases and backups
• End-to-end: only sender and recipient can read, not even the service
• For individual messages: S/MIME or OpenPGP for email

Real-world example: the stolen laptop

A wholesaler’s field sales rep has his laptop stolen from his car. It holds customer lists, price calculations and locally stored quotes. If the hard drive is not encrypted, it is enough to remove it or boot the device from a USB stick to read all the data.

If the device is encrypted with BitLocker and protected by the sign-in and a TPM chip, the drive remains an unreadable block for the thief. What could have been a data protection incident usually becomes a hardware loss, and the recovery keys sit safely in central device management rather than on a slip of paper.

Key management, limits and imple­menta­tion

The strength of encryption lies in how the keys are handled. If they are lost, your own data is irretrievably lost too; if they sit unprotected next to the data, the encryption achieves little. It also only protects in the relevant state: on a running, unlocked computer, data is readable. For the future, experts are working on methods that also withstand quantum computers; first standards were published in 2024.

Nano Concepts sets up disk encryption, HTTPS with current certificates and encrypted backups, plans key management and checks existing systems for outdated methods. The result is a transparent concept that reconciles data protection and practice without slowing employees down in daily work.

• Recovery keys not backed up
• Outdated protocols and expired certificates in use
• Passwords stored unprotected in spreadsheets or sent by email
• Backups and portable media remain unencrypted