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DCT-4加密技术讨论
发布时间：2007-10-22 12:00:00 浏览次数: 844
DCT-4加密技术讨论 U"`5% (
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CPU加密解析： > /A}6@T
R69pYwrCH
ARM scrambling system on DCT-4 g7L$ ?CV@
****************************** OreG t9
wMkG@H7
Decrypt 8!|Mi^j#
" H=FvD.j
edx = address (even) n4<Sec 7
******************************** @}7u`qWp
nex_d: mov ax,[esi+edx] 1-E obQ
call d_ax ;data scramble &fd'!|4{
call a_ax ;address scramble ?r(8*:l$O
mov [esi+edx],ax ebDk?MJ<4
add edx,2 ] ,>E8`+u
loop nex_d @Rq7Ml-
YW_Da_$
ret qt,1)OIJ
******************************** \$1h H~|
G kyyYwMB
J0SzM _&)
Data scramble |$?=S
d_ax: push ebx edx =qW]Y6
mov ebx,0 KZ*I_UKb
mov dx,0 R %xSvUh
nex_d_ax: shr ax,1 8"q+2+W8lp
jnc no_xr_d 'MyeN<9Kr
xor dx,[t_d+ebx] 9|q2n{R}W
no_xr_d: add ebx,2 } XLb5
cmp ebx,32 /VqU\LL
jb nex_d_ax .Ka +! $
mov ax,dx eIqa2Ee^
pop edx ebx "N="qcwAj
ret W83fPjY_g
!VRLZ JSF@
NOTE! It seem that this table depend on key on FLASH !Y5RbDY
t_d dw 0001h,2002h,0204h,0009h,0010h,0820h,0140h,00a0h,0102h,1200h,8400h,0808h,1080h,2010h,4404h,8040h D 4Z |gNqw
e[>2O},A
drk9n `:
****************************************** J#+?(=>^
Encrypt AwI2 LhRD
,Yh)~&2
;First you have to generate reverse function of d_ax bhAtm; 6
$B4K lV
call set_r_ax N*s+9$
tzjmzFb3
**************** ^J qAL
;edx = address (even) 8'p7`{J1
K!bnR7;!
nex_enc: mov ax,[esi+edx] .n6[F!9|y
call a_ax ;address scrambling F43Cb;24 E
call r_ax ;reverse data scrambling (.,Yx<3c
mov [esi+edx],ax K+GrS*32
add edx,2 feWM'0U
loop nex_enc &sF8lm(/
a0b )X;
ret 4$xR (=;'
****************************************** 8[SKZ
RKg|17PQ
T]F9e **
(QB}OMbA.
n),f}Gu,)X
set_r_ax: mov dx,0 i <o r<J
nex_sr_ax: mov ax,dx kJDK['&
call d_ax AGoCG 0>[?
movzx eax,ax (5wj
mov [r_ax_table+eax*2],dx NB +;
inc dx ~, ,=]p:F
jnz nex_sr_ax ZOL@(IA ?S
ret 0u+PF \
L a67T2{
r_ax: movzx eax,ax OotK+Q|[
mov ax,[r_ax_table+eax*2] bx/Y\y9
ret U]&BYH
kkM7zH
r_ax_table dw 10000h dup (0) 1H7*)%+z K
F2$#};L\
tL-_wi
tVGS2zD
A way to get easy data & address scrambling params x m5<Fcyk)
************************************************** mgqG##G
ZVI v H@R
Getting Data params. Z b8~({V
64v *.Q4
1.) Read crypted & decrypted data from DCT4 phone using "dct4_rd.com" +n { ^efH
Qp#{^qwB
2.1) Write to some FLASH even address word 0001h o o^b~2+
2.2) Read word from that address in decrypted mode and update first <OB034V)
word in table "t_d" 0pW[Gi l
2.3) Repeat steps 2.1 & 2.2 with words 0002,0004,0008,..to 8000h k"ZR\ 6 og
and update table "t_d" p]1(_:
2.4) Write to same FLASH addr. word 0000 G@\G9.PJ
2.5) Read decrypted word and xor all 16 words in table "t_d" with it. 3^l^
hZzzY=}3
Getting Address params. c K@Pqmms.
ZD,~fR!_9_
After getting data params, use function d_ax on whole crypted FLASH nx hY7
word by word. M0r,r$!`/
Now, xor word by word that data with decrypted FLASH, and that's it! h"U{L
DqPrCcl
And function a_ax will be: =2 ;5O,vo
'U(-SkCC
a_ax: xor ax,[edx+address_params-FLASH_offset] v"2lIW/s
ret B( U"\Ah$
n_nOJAc]
OpAJ}LD
[h],/WUV
?NXWk2 \
-------------------------------------------------------------------------------- s`8DJ\vBZ
以下内容只有回复后才可以浏览 aQsj blKtO
Q/R1Cqem}
|,`./{RFP
C0`t& r]
IMEI加密解析： g,o T0`T
%F7xbj
Hint: .HFaXp\0nN
010000000 Plain FLASH base 7YeQAKW;
090000000 Cipher FLASH base icB;1+e
(] w@=,
}\~.{ jaW
########################################### v@*>T*ih
; Get_IMEI >I,1JyQ
########################################### F|!dr&0Sc
;r0 = dest :jy\"B$
;RET r0 = status; 1=OK |F%T &DY z
;If IMEI is BAD dest will be filled with FF,FF,FF,.... ("?????...." em%' lP :
H O{ GfK*
002B2E2C: B5 30 PUSH (R4,R5,LR) wo}j
002B2E2E: B0 82 SUB SP,#0008 jUYt} -
[SDF z`/
;========================================== M5Tuy*<
; get IMEI from flash q=]ls1 `ts
[ +M?zK&
002B2E30: 1C 04 ADD R4,R0,#0 ;r0 = dest z_(a uQk
002B2E32: 21 0D MOV R1,#0D ;offset ;^x T<z>4i
002B2E34: 22 10 MOV R2,#10 ;size ~,IB<=_X;
002B2E36: F0 00 F9 AD CALL 002B3194 ;Get_secure_data_from_FLASH (GET IMEI) ^VQsW
7.uI3uW
002B2E3A: 1C 05 ADD R5,R0,#0 {PA b?Fn,
002B2E3C: 2D 01 CMP R5,#01 ]~@0&JGq
002B2E3E: D1 1A BNE 002B2E76 ;jmp if IMEI FLASH is NOT VALID! vc( tg Y
AM=7 )kT
;========================================== lX//Ind?;0
; get IMEI from UEM TIN@/M{-q1
QX] z%.
002B2E40: 46 68 MOV R0,SP ;r0 = dest (SP_LOC[8]) I;}Q#7O2
002B2E42: F0 00 F9 DF CALL 002B3204 ;READ_UEM_IMEI r0 = dest /TXIx"M%C
002B2E46: 1C 05 ADD R5,R0,#0 ;r5 = status ZGS*?$n l
002B2E48: 2D 01 CMP R5,#01 C>9e$#
002B2E4A: D1 0B BNE 002B2E64 ;jmp if UEM IMEI is zero (00,00,00,...) P++sea0
h J ,~
;========================================== fr7|LS'\
; compare UEM & FLASH IMEI ^zUm4gO+
>8pT[t:)^<
002B2E4C: 46 69 MOV R1,SP ;r1=UEM IMEI, r4=FLASH IMEI pdmt _"|!
002B2E4E: 20 00 MOV R0,#00 Xb K, l<
002B2E50: 5D 03 LDRB R3,[R0+R4] ({ P )4N
002B2E52: 78 0A LDRB R2,[R1+#00] w'ZSLeGu0
002B2E54: 42 93 CMP R3,R2 ^KBC"UW
002B2E56: D1 08 BNE 002B2E6A ;jmp if there is difference! rkr=>v?=
002B2E58: 31 01 ADD R1,#01 kr8uzx'
002B2E5A: 1C 40 ADD R0,R0,#1 Wi5=G0
002B2E5C: 04 00 LSL R0,R0,16 rOX# P-
002B2E5E: 0C 00 LSR R0,R0,16 ]i*m"Q
002B2E60: 28 08 CMP R0,#08 $zfy5{ M
002B2E62: DB F5 BLT 002B2E50 _pr_"54
LRR>xPC^B
;========================================== %+khe;7%
002B2E64: 2D 00 CMP R5,#00 ~< g;yf
002B2E66: D0 01 BEQ 002B2E6C ^"..; RV
002B2E68: E0 05 JMP 002B2E76 oDB[<w[~
tBC:ZBJ:f
002B2E6A: 25 00 MOV R5,#00 R@nT R
002B2E6C: 20 03 MOV R0,#03 SA8/TI`
002B2E6E: F0 00 F8 67 CALL 002B2F40 ;Get_sys_flag %`!"uXAJ&~
002B2E72: 28 02 CMP R0,#02 VclKqD,>
002B2E74: D0 09 BEQ 002B2E8A of;:R4mG
hP |:!6L
002B2E76: 2D 01 CMP R5,#01 uX7#: [V
002B2E78: D0 07 BEQ 002B2E8A (<$B&ZV2!
s>5Nvo& *
;========================================== gf<`A8!_
; fill dest with "FF" if IMEI is BAD! \-W]Y!m@.
w<TrRKcM
002B2E7A: 21 FF MOV R1,#FF |YbAB<q
002B2E7C: 20 00 MOV R0,#00 "rUS:`WG
002B2E7E: 55 01 STRB R1,[R0+R4] _ Ux>lFp
002B2E80: 1C 40 ADD R0,R0,#1 {;<>-
002B2E82: 04 00 LSL R0,R0,16 `XpG~o,!H
002B2E84: 0C 00 LSR R0,R0,16 N^ "]^F
002B2E86: 28 10 CMP R0,#10 !ciOgh>M
002B2E88: DB F9 BLT 002B2E7E {Vyc:
RQ/ +d.r
002B2E8A: 20 01 MOV R0,#01 9buzk0
002B2E8C: B0 02 ADD SP,#0008 4,CAmlhHo
002B2E8E: BD 30 RET (R4,R5) p. (v4L9
FQ^}@L6&
/*)Yjs#'x=
######################################## 1dW6S&>&
Get_secure_data_from_FLASH QN4P7J
######################################## 4+jn6i/OH
;r0 = dest X8M E3R
;r1 = offset in FLASH secure data block sWn<M*:rZ
;r2 = size in bytes T 35L!*S
;RET r0 = status ;1=OK (in dest is valid data), else ERROR (dest is filed by FF...) JB RhNB
;======================================= gm]mJr:
J*I(],u}<
002B3194: B5 F0 PUSH (R4,R5,R6,R7,LR) {i4|[ m6h
002B3196: B0 81 SUB SP,#0004 (3G!7n2
002B3198: 1C 14 ADD R4,R2,#0 -Zyf >Q
002B319A: 91 00 STR R1,[SP+#0000] ;save PARAM R1 (offset) =_7Y,Svk?7
002B319C: 1C 06 ADD R6,R0,#0 xnQLFiyL
X!W"'% v
MO ,?5
;======================================= !h,23UH
;copy SECURE FLASH cipher block of 28h bytes from FLASH 900003ah to temp RAM 43d14h Y\- Sm
^I1<j`1
002B319E: 4D 5B LDR R5,[PC+#016C] ;[002B330C]=00043D14 ;r5 = temp baf BsZ$FTz~
002B31A0: 49 5E LDR R1,[PC+#0178] ;[002B331C]=0900003A ?E"K\T6[2
002B31A2: 1C 28 ADD R0,R5,#0 E t]Rk5I
002B31A4: 22 28 MOV R2,#28 sUW #{1(y
002B31A6: 4B 5C LDR R3,[PC+#0170] ;[002B3318]=00043FD0 h aFMU`daZ
002B31A8: 68 1B LDR R3,[R3+#00] ;=840001 5yFa4JBM8!
002B31AA: 46 FE MOV LR,PC vcB51J
002B31AC: 47 18 BX R3 ;call 840001 (ROM_SEC__COPY_MEM r0=dest r1=src r2=size) \@|+Fu
uid[tLR{55
;======================================= x ?{=1 ?`
;decode SECURE FLASH cipher block r1!Z7,
%pGKKbvM
002B31AE: 1C 28 ADD R0,R5,#0 ;r0,r1 = src,dst Pb5c}j
002B31B0: 1C 29 ADD R1,R5,#0 g,qe0^N4
002B31B2: 22 28 MOV R2,#28 ;size j]0&t;
002B31B4: 23 20 MOV R3,#20 ;decryption mode Z)CFq{TeE
002B31B6: F7 FF FF 64 CALL 002B3082 ;DECRYPT_DATA P9\ w::6
002B31BA: 1C 07 ADD R7,R0,#0 ;r7 = decrypt status /-I1#NU
d#? ^^&.
;======================================= 'dChQhG}
; calc checksum of decrypted SECURE FLASH block and test if it is correct 8A*IHpY
YAnD x<*)
002B31BC: 1C 28 ADD R0,R5,#0 ;r0 = src ^=]N(,v
002B31BE: 21 26 MOV R1,#26 ;size % -'=G
002B31C0: F7 FF FF 84 CALL 002B30CC ;CALC_SUM (ret r0=chk) #KvDG U>
002B31C4: 21 26 MOV R1,#26 [@~@y)/.
002B31C6: 5D 49 LDRB R1,[R1+R5] f j?,Qa
002B31C8: 02 0A LSL R2,R1,8 '-WrcT
002B31CA: 21 27 MOV R1,#27 Wf7*tsWZ
002B31CC: 5D 49 LDRB R1,[R1+R5] M{;qp>
002B31CE: 43 11 ORR R1,R2 ;r1 = chk from SECURE FLASH block UH?~Pi)LU
002B31D0: 42 88 CMP R0,R1 18f8@ N
002B31D2: D1 0A BNE 002B31EA ;jmp if checksum is BAD! r?DPR3E{eS
+ntLs;H
002B31D4: 2F 01 CMP R7,#01 *T FNs,[
002B31D6: D1 0D BNE 002B31F4 ;jmp if decrypt status is BAD! uA.9:d y_
1D l)T!7
;======================================= $_Q^o4P
; copy from SECURE FLASH decrypted block offset*size to dest (for IMEI offset=dh,size=10h) YFQ^a t+
c#_bfx-f
002B31D8: 4B 4F LDR R3,[PC+#013C] ;[002B3318]=00043FD0 QEJ< *$"
002B31DA: 98 00 LDR R0,[SP+#0000] ;PARAM R1 (offset) C*uOCW(
002B31DC: 19 41 ADD R1,R0,R5 ;r1 = temp_baf+offset Fk"5n9ys
002B31DE: 1C 30 ADD R0,R6,#0 ;r0 = PARAM R0 (dest) s+~U x3P
002B31E0: 1C 22 ADD R2,R4,#0 ;r2 = PARAM R2 (size) iJz J% Y
002B31E2: 68 1B LDR R3,[R3+#00] ;=840001 %F;* `#
002B31E4: 46 FE MOV LR,PC 08}.j=a
002B31E6: 47 18 BX R3 ;call 840001 (ROM_SEC__COPY_MEM r0=dest r1=src r2=size) Q`{OKt+ !
002B31E8: E0 04 JMP 002B31F4 ,w[<R o
Ir9R3h^.
;======================================= n (@e~_
; If FLASH IMEI have any error dest will be filled with "FF"..... s~Ct >ou
<v^3g0'l[
002B31EA: 1C 22 ADD R2,R4,#0 ;r2 = PARAM R2 (size) )< }bZ33d
002B31EC: 1C 30 ADD R0,R6,#0 ;r0 = PARAM R0 (dest) r;U {,?b Q
002B31EE: 21 FF MOV R1,#FF ;r1 = fill value E''?
002B31F0: F1 86 FE 0C CALL 00439E0C ;FILL_MEM p(T!rU}
)`3W<q~Br
;======================================= $x fKUUvv
; fill temp_baf to make HACKING harder Uz0MRf0e#
x&+ ne
002B31F4: 1C 28 ADD R0,R5,#0 ;r0 = temp_baf 51;/(GR.
002B31F6: 21 FF MOV R1,#FF ;r1 = fill value }%nC_:)Tm
002B31F8: 22 28 MOV R2,#28 ;size Nwe;;P+
002B31FA: F1 86 FE 07 CALL 00439E0C ;FILL_MEM `+ ;xu *
.>$YIA
002B31FE: 1C 38 ADD R0,R7,#0 -$u$.wo"
002B3200: B0 01 ADD SP,#0004 (/u}B
002B3202: BD F0 RET (R4,R5,R6,R7) sh[a3 At
;************************************************ ]1~c= -O
CGx%$LJ
;################################################ <*5df$6 &@
READ_UEM_IMEI 8 }0 lax=
;################################################ UY*^| I
;r0 = dest Jy< D_n
;RET r0 = status; 1=IMEI is not zero (00,00,00,....) ZByy}#,$
hPi.f
002B3204: B5 F0 PUSH (R4,R5,R6,R7,LR) V5N!n>8i6
002B3206: 1C 04 ADD R4,R0,#0 \xvD) '2
002B3208: 26 04 MOV R6,#04 ;read 4 registers cQ iAFV!
002B320A: 4D 48 LDR R5,[PC+#0120] ;[002B332C]=014AE414 ;IMEI reg:mask table (1b,1c,1d,1e, mask=ffff) 1;P3w# {?
002B320C: 27 00 MOV R7,#00 KI , *]Yr
-ly*~"
002B320E: 68 28 LDR R0,[R5+#00] ;r0 = reg:mask II>3sVh&A
002B3210: F0 01 FD 99 CALL 002B4D46 ;READ_UEM_REG t3oMAkQkk
002B3214: 04 00 LSL R0,R0,16 ;r0 = reg value " B}ebXS)1
002B3216: 0C 00 LSR R0,R0,16 *KT1#Ao
002B3218: 2F 00 CMP R7,#00 " /O1?u<r
002B321A: D1 02 BNE 002B3222 @oprP%n
002B321C: 28 00 CMP R0,#00 !g}X%tLWsa
002B321E: D0 00 BEQ 002B3222 OQk]Tf?
002B3220: 27 01 MOV R7,#01 2%4MF _CnL
002B3222: 0A 01 LSR R1,R0,8 xT`9UNQASw
002B3224: 70 21 STRB R1,[R4+#00] ;wr reg value H to dest dzvBZNXG
002B3226: 34 01 ADD R4,#01 @kgzX:1+
002B3228: 70 20 STRB R0,[R4+#00] ;wr reg value L to dest `g^[%['eY8
002B322A: 34 01 ADD R4,#01 T9Dlo9rL=
002B322C: 35 04 ADD R5,#04 !8^D]DgcJ
002B322E: 3E 01 SUB R6,#01 I]uP p
002B3230: D1 ED BNE 002B320E Nkgo2o i
~`Qbw,
002B3232: 1C 38 ADD R0,R7,#0 & b FQ
002B3234: BD F0 RET (R4,R5,R6,R7) O;AE{eM~_#
;************************************************ ZN J:>}^
Hs]"Q@l2
004AE414: 00 1B ;IMEI UEM TABLE $\KET,`o
004AE416: FF FF Hc8>4%:D
004AE418: 00 1C R`< %+do
004AE41A: FF FF 1e'+g7<
004AE41C: 00 1D Tq < &
004AE41E: FF FF r f5m5A4S
004AE420: 00 1E 6} \> %0
004AE422: FF FF RZ :* P:
;************************************************ L{UyMEMG5
)\l< -Q.a
yZ5}`T^}Bg
B.R. <Fxv5B^5
Dejan Kaljevic |i.Bw8P[
:Jh.|{zO
%sU>>tR}
]w.Z%B
DCT4采用了ARM7 MCU core＋TI320C54X DSP core的基带架构、如上是以8310为例的硬件ID验证和IMEI验证 >_3?!<;G
2oa< ;a$h
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