Base64

Rare card · No. 20259

Base64 is a binary-to-text encoding that uses 64 printable characters to represent each 6-bit segment of a sequence of byte values. As for all binary-to-text encodings, Base64 encoding enables transmitting binary data on a communication channel that only supports text. When comparing the original data to the resulting encoded data, Base64 encoding increases the size by 33% plus about 3% additional if inserting line breaks for typical line length. The earliest uses of this encoding were for dial-up communication between systems running the same operating system – for example, uuencode for UNIX and BinHex for the TRS-80 (later adapted for the Macintosh) – and could therefore make more assumptions about what characters were safe to use. For instance, uuencode uses uppercase letters, digits, and many punctuation characters, but no lowercase.

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