Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It converts binary data into a set of 64 characters (hence the name Base64), which are safe for transmission over text-based protocols, such as email or HTML. Each Base64 character represents 6 bits of the original data, making it an efficient way to encode binary information into a plain text string. It is commonly used for encoding binary data, such as images or files, for safe transmission over text-based channels.