I am now going to show you some encrypted data. To do this I will use ROM's from Street Fighter Zero revisions 950627 and 950727 along with Street Fighter Alpha. Only one ROM from each game board contains the encrypted data in question, it sits in socket 3 of the game board. I am also going to use the one equivalent ROM from the CPS Changer version of Street Fighter Zero. This is the same as its CPS-2 counterparts but is non encrypted. If you have the ROM dumps of these games the checksums for these ROM's are;
 

Street Fighter Zero (rev. 950627) :	844220c2
Street Fighter Zero (rev. 950727) :	f5444120
Street Fighter Alpha (rev. 950727) :	ebf2054d
Street Fighter Zero (Changer) :	1140743f

Before I looked at any data from these ROM's they had to be byte swapped. If your going to compare data from this page with your ROM's you must byte swap them before the data here will match up. From now on all references to Street Fighter Zero revisions 950627 / 950727 and Street Fighter Alpha will be as SFz1, SFz2 and SFa. References to Street Fighter Zero (CPS Changer) will be as SFzch. With these details out the way lets make a start.
 
Below you will see the standard Motorola 68000 vector table entries for each ROM. These vectors are located from address $00 to $FF and I've listed what each does. I've also highlighted the encrypted data and relevant SFzch parts white.
 

	SFzch	SFa	SFz1	SFz2
SYSTEM SSP  $00  SYSTEM PC  $04  BUS ERROR  $08  ADDRESS ERROR  $0C  ILLEGAL INSTRUCTION  $10  DIVISION BY ZERO  $14  CHK EXCEPTION  $18  TRAPV EXCEPTION  $1C  PRIVILEGE VIOLATION  $20  TRACE EXCEPTION  $24  LINE-A EMULATOR  $28  LINE-F EMULATOR  $2C  RESERVED BY MOTOROLA  $30  RESERVED BY MOTOROLA  $34  RESERVED BY MOTOROLA  $38  RESERVED BY MOTOROLA  $3C  RESERVED BY MOTOROLA  $40  RESERVED BY MOTOROLA  $44  RESERVED BY MOTOROLA  $48  RESERVED BY MOTOROLA  $4C  RESERVED BY MOTOROLA  $50  RESERVED BY MOTOROLA  $54  RESERVED BY MOTOROLA  $58  RESERVED BY MOTOROLA  $5C  SPURIOUS EXCEPTION  $60  INTERRUPT REQ LEVEL 1  $64  INTERRUPT REQ LEVEL 2  $68  INTERRUPT REQ LEVEL 3  $6C  INTERRUPT REQ LEVEL 4  $70  INTERRUPT REQ LEVEL 5  $74  INTERRUPT REQ LEVEL 6  $78  INTERRUPT REQ LEVEL 7  $7C  TRAP #00 EXCEPTION  $80  TRAP #01 EXCEPTION  $84  TRAP #02 EXCEPTION  $88  TRAP #03 EXCEPTION  $8C  TRAP #04 EXCEPTION  $90  TRAP #05 EXCEPTION  $94  TRAP #06 EXCEPTION  $98  TRAP #07 EXCEPTION  $9C  TRAP #08 EXCEPTION  $A0  TRAP #09 EXCEPTION  $A4  TRAP #10 EXCEPTION  $A8  TRAP #11 EXCEPTION  $AC  TRAP #12 EXCEPTION  $B0  TRAP #13 EXCEPTION  $B4  TRAP #14 EXCEPTION  $B8  TRAP #15 EXCEPTION  $BC  RESERVED BY MOTOROLA  $C0  RESERVED BY MOTOROLA  $C4  RESERVED BY MOTOROLA  $C8  RESERVED BY MOTOROLA  $CC  RESERVED BY MOTOROLA  $D0  RESERVED BY MOTOROLA  $D4  RESERVED BY MOTOROLA  $D8  RESERVED BY MOTOROLA  $DC  RESERVED BY MOTOROLA  $E0  RESERVED BY MOTOROLA  $E4  RESERVED BY MOTOROLA  $E8  RESERVED BY MOTOROLA  $EC  RESERVED BY MOTOROLA  $F0  RESERVED BY MOTOROLA  $F4  RESERVED BY MOTOROLA  $F8  RESERVED BY MOTOROLA  $FC	00FF8000 00000950 000000C0 000000CC 000000D8 000000E6 000000F4 00000102 00000110 0000011E 0000012C 0000013A 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000148 00000148 00001068 00000148 00000148 00000148 00000148 00000148 0000119A 00001200 00001254 00001312 0000133C 00001362 0000137E 000011D8 00001284 00001222 000011BC 000012CC 00001392 00000148 00000148 00000148 33FC0000 00FF0000 508F607E 33FC0001 00FF0000 508F6072 007C2600 33FC0002 00FF0000 6064007C 260033FC 000300FF 00006056 007C2600 33FC0004 00FF0000	F058C474 1E4C719F 000000C0 000000CC 000000D8 000000E6 000000F4 00000102 00000110 0000011E 0000012C 0000013A 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000148 00000148 000011DE 00000148 00000148 00000148 00000148 00000148 0000132C 00001392 000013E6 000014A4 000014CE 000014F4 00001510 0000136A 00001416 000013B4 0000134E 0000145E 00001524 00000148 00000148 00000148 DA068640 CE49F5CA 65594489 E632FF36 FBA89D62 CCFF1531 5DF1A281 17CEFA2D FF9D432F D9657FC4 1AE1D59E 9E15F466 5D1F8779 A88034DC 27E7B4F3 D59D0E16	6FC42E65 4A447A0A 000000C0 000000CC 000000D8 000000E6 000000F4 00000102 00000110 0000011E 0000012C 0000013A 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000148 00000148 000011DE 00000148 00000148 00000148 00000148 00000148 0000132C 00001392 000013E6 000014A4 000014CE 000014F4 00001510 0000136A 00001416 000013B4 0000134E 0000145E 00001524 00000148 00000148 00000148 437E59E4 D5C8A559 4ABE285A 0A6A7F4E 076EB1E4 B9A67B9F 8D363FD1 CD546A05 166D2BB6 09422434 93E3A7E4 A6BECB9E F1818F6F 0D4B990E A35405EC 7651700F	6FC42E65 4A447A0A 000000C0 000000CC 000000D8 000000E6 000000F4 00000102 00000110 0000011E 0000012C 0000013A 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000148 00000148 000011DE 00000148 00000148 00000148 00000148 00000148 0000132C 00001392 000013E6 000014A4 000014CE 000014F4 00001510 0000136A 00001416 000013B4 0000134E 0000145E 00001524 00000148 00000148 00000148 437E59E4 D5C8A559 4ABE285A 0A6A7F4E 076EB1E4 B9A67B9F 8D363FD1 CD546A05 166D2BB6 09422434 93E3A7E4 A6BECB9E F1818F6F 0D4B990E A35405EC 7651700F

As you can see only the very top and bottom of the vector table is encrypted, the rest is not although some numbers are slightly different as would be expected (marked blue). The reserved vectors from $C0 to $FC contain program code for the vectors I've marked in green and I feel that once non encrypted this code will be the same as SFZch.
 
After matching code from these ROM's as explained in my first report here I suspect the Program Counter will equal $00000988 in all encrypted ROM's once non encrypted and not $00000950 as SFzch does.