An instance of Base64Codec.
This instance provides a convenient access to base64 encoding and decoding.
It encodes and decodes using the default base64 alphabet, does not allow any invalid characters when decoding, and requires padding.
Examples:
var encoded = BASE64.encode([0x62, 0x6c, 0xc3, 0xa5, 0x62, 0xc3, 0xa6,
0x72, 0x67, 0x72, 0xc3, 0xb8, 0x64]);
var decoded = BASE64.decode("YmzDpWLDpnJncsO4ZAo=");