What is Base64?

Base64 is a group of binary-to-text encoding schemes that represent binary data in an ASCII string format by translating the data into a radix-64 representation. Base64 is designed to carry data stored in binary formats across channels that only reliably support text content.

Why Base64?

Base64 is commonly used to encode data, and the same holds true in many Capture The Flag (CTF) competitions. Some competitions use it as a weak form of encryption or to encode data that makes up a challenge. Thus, it is usefull to know in CTF competitions.

Recognizing Base64

What sets Base64 and other radix encodings appart from other encodings/ciphers are the = padding characters at the end and its lack of spaces. For example, Tm90aWNlIHRoZSBlcXVhbCBzaWducw== is a Base64 encoded string. Base64 strings can be decoded by various online tools, such as CyberChef.