How were BIP32 version bytes determined? [SOLVED]

[JayCoin]

BIP32 version bytes for public and private keys are

PUBLIC = 0x0488b21e
PRIVATE = 0x0488ade4

How were these determined so that the prefixes of extended keys start with "xpub" and "xprv" ?

Was it guess and check?

I want to come up with some version bytes for some altcoins that don't have standard version bytes yet.

[DannyHamilton]

Write out what you want the version bytes to say.

Convert from base 58 to hex (base 16).

Done.

[JayCoin]

It was a little harder than that. The bytes don't line up between base58 and hex. I used a little trial and error. I bet if I was better with base58 math then it would be easier.

here are some bip32 numbers I came up with for Namecoin:

Private: 0x01c5c63d  = "Nprv"
Public: 0x01c5ca77 = "Npub"