FAQ

Developer Questions

How can you represent binary image data in XML using plain text?

Binary data is represented in XML using Base64 encoding See RFC 1341 Section 5.2. Binary data is a string of numbers in base 2 represented by a series of bits (binary digits). These same numbers can be represented in base 64 using a series of base 64 digits. The convention for representing base 64 digits is to use the upper and lower case letters (52 digits), the numbers (+10 digits), and two punctuation characters '+' and '/' (total = 64).

Since each byte can represent a value from 0 to 255, we would need two base 64 digits to represent it. If we did that, we would need twice the storage to convert binary into plain text. Instead we can convert 3 bytes at a time into 4-digit base 64 numbers. This makes the plain-text representation of binary data "only" 1/3 larger.