[sfoley]

Base64 costs 1.3x space, not 4x.

[collinmanderson]

Ohh, I was thinking 256/64 = 4x, but it's apparently it's 8 bits / 6 bits = 1.3333x. Thanks. Plus for email a little extra for a =\r\n on every line, so more like 1.4x.