Encryption is the process of converting readable data (plaintext) into unreadable ciphertext using an algorithm and a secret key. Only someone holding the correct key can reverse the process, called decryption, and recover the original data.
Why it matters
Encryption protects confidentiality when data crosses networks you do not control or sits on disks that could be lost or stolen. It is the foundation of HTTPS, secure messaging, disk protection and password storage workflows. Without it, anyone who can observe the traffic or the storage can read the content. Encryption does not by itself prove who sent the data or that it was not altered, which is why it is paired with signatures and message authentication.
Example
A website served over HTTPS encrypts each request and response with TLS. A login form submitting password=hunter2 travels as unreadable ciphertext, so someone on the same coffee-shop Wi-Fi sees only random-looking bytes and the destination hostname.
Common mistakes
- Rolling your own cipher instead of using a vetted library and a standard algorithm such as AES.
- Storing the key next to the encrypted data, which makes the encryption pointless.
- Believing encrypted means anonymous: metadata such as who talked to whom is often still visible.
Related
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