The CD_key are not on the reg.
They are encrypted in MPQ files in D2 folder
Once again, here they are :
data\global\sfx\cursor\curindx.wav - User Name (d2sfx.mpq)
data\global\sfx\cursor\wavindx.wav - Regular key (d2sfx.mpq)
data\global\chars\am\cof\amblxbow.cof - Expansion key (d2char.mpq).