[noglorp]

I still don't follow. Digit value rather than ASCII code... you mean Base64 digit value? If so, do you just ignore the pad char? (I mean... by "non-digit leaves" you are referring to the leaves represented by '=' and only those?)

EDIT: I understand now... jeez that was a run-around! Ascii encoded decimal! Thanks for the clarifying replies all over.

[zwieback]

I think it's literally one ASCII code (byte) per each of the 1023 nodes in the tree. Any time there's a non-digit in one of the leaf positions you ignore it.

[drdo]

There's no Base64, it's just regular ASCII, for each leaf that has an ASCII character '0' through '9', you sum 0 through 9 respectively.