Understand Base64 encoding, why it is used for data transmission, its mathematical padded structure, and why Base64 is not encryption.
Frequently Asked Questions
Q1. What is Base64 encoding used for?
Base64 encoding is used to safely transmit binary data (such as images, PDF files, or encrypted keys) over text-based networks and protocols like HTTP, SMTP email, XML, or JSON without corruption caused by special binary characters.
Q2. Is Base64 secure or encrypted?
No. Base64 is strictly an encoding format, not encryption. Anyone can decode Base64 encoded text back into plain binary data instantly using standard browser utilities or command-line tools.
Q3. Why does Base64 data end with equals signs (=)?
Base64 processes data in 3-byte (24-bit) groups. If the input data length is not evenly divisible by 3, trailing "=" characters are added as padding so the output decoder knows how many trailing bits are padding.
Q4. How much larger does data become after Base64 encoding?
Base64 encoding increases file size by approximately 33%. Every 3 bytes (24 bits) of original binary data expand into 4 bytes (24 bits) of ASCII characters.
Q5. How do I decode Base64 in JavaScript?
In browser JavaScript, use atob("base64String") to decode and btoa("plainText") to encode. In Node.js, use Buffer.from("base64String", "base64").toString("utf-8").