Encoding vs encryption vs hashing

Encoding changes data into another format so it can travel or be stored, and anyone can reverse it: there's no secret. Encryption keeps data confidential, and only someone with the key can reverse it. Hashing makes a fixed-length fingerprint of data, and nobody can reverse it. Base64 is encoding, AES is encryption, SHA-256 is hashing.

Data encoding is a set of rules for writing data in a particular form. UTF-8 writes text as bytes. Base64 writes bytes as letters and digits so they survive email and JSON. URL encoding writes characters that aren't allowed in a URL as % codes. In every case the rules are public, and decoding is just running them backwards.

The word means other things elsewhere, such as how memories form in psychology, or how video is compressed. Here it's only about representing data.

No, and treating it as if it were is a common mistake. Base64 hides nothing: anyone can decode it in a second, with no key. A password or token that's "only Base64" is effectively plain text. If something needs to stay secret, encrypt it.

Hashing is the odd one out because it doesn't keep the data at all. That makes it right for checking things, such as whether a download is intact or a password is correct, and wrong for anything you need to read again. Hashing vs encryption goes into that difference and into password storage.