DS1963S

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SHA-1 Input Message Formats (continued) Table 2

Validate Data Page, Sign Data Page, Authenticate Host, Compute First Secret, Compute Next Secret

M0[31:24] = (SS+0)

M0[23:16] = (SS+1)

M0[15:8] = (SS+2)

M0[7:0] = (SS+3)

M1[31:24] = (PP+0)

M1[23:16] = (PP+1)

M1[15:8] = (PP+2)

M1[7:0] = (PP+3)

M2[31:24] = (PP+4)

M2[23:16] = (PP+5)

M2[15:8] = (PP+6)

M2[7:0] = (PP+7)

M3[31:24] = (PP+8)

M3[23:16] = (PP+9)

M3[15:8] = (PP+10)

M3[7:0] = (PP+11)

M4[31:24] = (PP+12)

M4[23:16] = (PP+13)

M4[15:8] = (PP+14)

M4[7:0] = (PP+15)

M5[31:24] = (PP+16)

M5[23:16] = (PP+17)

M5[15:8] = (PP+18)

M5[7:0] = (PP+19)

M6[31:24] = (PP+20)

M6[23:16] = (PP+21)

M6[15:8] = (PP+22)

M6[7:0] = (PP+23)

M7[31:24] = (PP+24)

M7[23:16] = (PP+25)

M7[15:8] = (PP+26)

M7[7:0] = (PP+27)

M8[31:24] = (PP+28)

M8[23:16] = (PP+29)

M8[15:8] = (PP+30)

M8[7:0] = (PP+31)

M9[31:24] = (SP+8)

M9[23:16] = (SP+9)

M9[15:8] = (SP+10)

M9[7:0] = (SP+11)

M10[31:24] = MPX

M10[23:16] = (SP+13) M10[15:8] = (SP+14)

M10[7:0] = (SP+15)

M11[31:24] = (SP+16) M11[23:16] = (SP+17) M11[15:8] = (SP+18)

M11[7:0] = (SP+19)

M12[31:24] = (SS+4)

M12[23:16] = (SS+5)

M12[15:8] = (SS+6)

M12[7:0] = (SS+7)

M13[31:24] = (SP+20) M13[23:16] = (SP+21) M13[15:8] = (SP+22)

M13[7:0] = 80h

M14[31:24] = 00h

M14[23:16] = 00h

M14[15:8] = 00h

M14[7:0] = 00h

M15[31:24] = 00h

M15[23:16] = 00h

M15[15:8] = 01h

M15[7:0] = B8h

Legend

Mt

Input buffer of SHA engine

0

£ t £ 15; 32-bit words

SS

Starting address of secret

See Figure 5, Memory Map, memory pages 16 and 17

With Compute First Secret the secret data is replaced by all zeros.

PP

Starting address of memory page

See Figure 5, Memory Map, memory pages 0 through 15

MPX

MPX[7] = Control bit M, see Figure 8

MPX[6] = Control bit X, see Figure 8

MPX[5:0] = (SP+12)[5:0]

(SP+n)

Byte n of scratchpad

The counting of n is in decimal

The SHA functions as well as the memory functions involve several flags that may affect the function

itself and the result of functions executed in subsequent steps. These flags are HIDE, CHLG, AUTH and

MATCH. Table 3 summarizes the operation of these flags. The only command that does not change any

flag is Read Scratchpad. Note that a power-on reset of the parasite-powered 1-Wire front end of the

device also affects the flags. This “Return to Probe” condition occurs typically when a DS1963S device

makes contact with a read/write probe of a host computer or bus master or if the connection is

intermittent. The most apparent is the HIDE-flag. If set it prevents the user from reading the data in the

scratchpad; the current value of the target address and E/S byte remain readable, though. The HIDE-flag

also affects the Write Scratchpad and Copy Scratchpad commands. The other three flags are used in

special situations only and remain cleared most of the time. The flags CHLG and AUTH act as a pair in

the host/user authentication process to ensure that commands are executed in a certain sequence. If the

sequence is correct and the subsequent Match Scratchpad command results in matching data, the

MATCH flag is set. The MATCH flag then may affect Validate Data Page, Sign Data Page or Read

Authenticated Page.