Scor­pio News

  

April–June 1988 – Volume 2. Issue 2.

Page 11 of 35

(XFCB)

G=00:06,​T=1,​S=7,​PS=1

Again, the XFCB structure is similar, but the header can extend from 10H to 1FH according to the user number. The “key” byte at entry 13 is again used to encrypt the password and store it in positions 16 to 23.

The Encryption

The “key” byte at entry 13 must be stored, along with the encrypted password, on the disk for the CCP to check if the correct password is specified. The key byte is constructed from the initial password specified in SET.COM, as shown below:

SET FRED.COM [PASSWORD=FRED]

Password = FRED^^^^ = 46+52+45+44+20+20+20+20 = 1A1H

A1H is therefore stored at entry 13 and used to encrypt the password in the following way:

FRED= 46 52 45 44 20 20 20 20
KEY= A1 A1 A1 A1 A1 A1 A1 A1
RESULT= E7 F3 E4 ES 81 81 81 81

The string is then reversed and stored in the XFCB position for the encrypted password.

Stored Encrypted Password = 81 81 81 81 E5 E4 F3 E7

Page 11 of 35