Advanced API Security: OAuth 2.0 and Beyond

© Prabath Siriwardena 2020

P. SiriwardenaAdvanced API Securityhttps://doi.org/10.1007/978-1-4842-2050-4_20

Base64 URL Encoding

Prabath Siriwardena¹ 

(1)

San Jose, CA, USA

 

Base64 encoding defines how to represent binary data in an ASCII string format. The objective of base64 encoding is to transmit binary data such as keys or digital certificates in a printable format. This type of encoding is needed if these objects are transported as part of an email body, a web page, an XML document, or a JSON document.

To do base64 encoding, first the binary data are grouped into 24-bit groups. Then each 24-bit group is divided into four 6-bit groups. Now, a printable character can represent each 6-bit group based on its bit value in decimal (see Figure E-1). For ...