Base64 changes the envelope, not the secret

A Base64 value may look opaque, but anyone who has it can decode it. Base64 is a way to represent bytes using a limited text alphabet. It does not provide confidentiality, prove authenticity, or require a secret key.

Run a text round trip

In Base64 Lab, choose UTF-8 text and Encode. Paste this exact text, including its space and accent.

Input: café ☕
Expected Base64: Y2Fmw6kg4piV
Expected UTF-8 byte count: 9

Now choose Decode and paste the expected Base64 value. The output must be café ☕. UTF-8 turns the text into bytes before Base64 represents those bytes. Decoding reverses both steps.

Binary bytes do not promise readable text

Choose Binary file and Decode, then paste:

Input: AP+A
Expected hex preview: 00 ff 80
Expected decoded byte count: 3

Those bytes are not valid UTF-8 text. In text mode, Diggwigs reports an error rather than replacing invalid bytes. In binary mode, you can inspect the hexadecimal preview and download the original three bytes as a file. Choosing a file for encoding reads it locally; the browser never uploads it.

Recognize a different alphabet

Standard Base64 uses letters, digits, +, and /. Padding uses =. Base64url substitutes – and _ and often omits padding. A token accepted by one convention may be rejected by another.

Input: SGVsbG8*
Expected: invalid standard Base64 error

Input: Zg==
Expected text: f

Diggwigs accepts standard padded Base64, with ASCII spaces or line breaks allowed for wrapped text. It checks the final padding bits too. If the value belongs to another format, identify that format before changing its characters.

Do not put secrets in Base64 and call them protected. An encoding changes representation; encryption requires a separate security design.