Editing Base64 (section)

===Decoding Base64 with padding===
When decoding Base64 text, four characters are typically converted back to three bytes. The only exceptions are when padding characters exist. A single <code>=</code> indicates that the four characters will decode to only two bytes, while <code>==</code> indicates that the four characters will decode to only a single byte. For example:

{| class="wikitable"
! Encoded !! Padding !! Length !! Decoded
|-
| {{mono|1=bGlnaHQg{{bg|lightgrey|2=dw==}}}}
| <code>==</code> || 1
| ''light {{bg|lightgrey|w}}''
|-
| {{mono|1=bGlnaHQg{{bg|lightgrey|2=d28=}}}}
| <code>=</code> || 2
| ''light {{bg|lightgrey|wo}}''
|-
| {{mono|1=bGlnaHQg{{bg|lightgrey|d29y}}}}
| {{CNone|None}} || 3
| ''light {{bg|lightgrey|wor}}''
|}
Another way to interpret the padding character is to consider it as an instruction to discard 2 trailing bits from the bit string each time a <code>=</code> is encountered. For example, when `{{mono|1=bGlnaHQg{{bg|lightgrey|2=dw==}}}}` is decoded, we convert each character (except the trailing occurrences of <code>=</code>) into their corresponding 6-bit representation, and then discard 2 trailing bits for the first <code>=</code> and another 2 trailing bits for the other <code>=</code>. In this instance, we would get 6 bits from the <code>d</code>, and another 6 bits from the <code>w</code> for a bit string of length 12, but since we remove 2 bits for each <code>=</code> (for a total of 4 bits), the <code>dw==</code> ends up producing 8 bits (1 byte) when decoded.