I have a technical question regarding the use of the addresses in section 4.2 of FIPS 205, the NIST standard of SPHINCS+. Taking for example the tree address, we want to copy an integer in big-endian byte type in the words 1,2 and 3 of the address (starting at 0). Hence, the lowest byte of my integer should be copy at the rightmost place of word 3.
Ex: For the tree address 0x782342FAB we get the tree address:
[0x00, 0x00, 0x00, 0x00 || 0x00, 0x00, 0x00, 0x07 || 0x82, 0x34, 0x2F, 0xAB]
Am I right? I do not see other good options, but since the addresses are used as parameter in hash functions, I wanted to be sure.