+ The result is calculated like this:
+
+ + Concatenate SEED and PASS and calculate the 16-byte MD5 checksum.
+
+ + Shorten the checksum to eight bytes by folding the second eight
+ bytes onto the first eight using XOR. The resulting eight-byte
+ sequence is the key.
+
+ + MD5-process the key, fold the checksum to eight bytes and store
+ it back to the key. Repeat this crunching SEQUENCE times.
+ (Sequence is a number that gets decremented every time the user
+ logs in to the server. Therefore an eavesdropper would have to
+ invert the hash function in order to guess the next one-time
+ password.)
+
+ + Convert the resulting 64-bit key to 6 English words separated by
+ spaces (see btoe for details) and return the resulting ASCII
+ string.
+
+ All this is described in section 6 of rfc2289 in more detail. */