mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 601

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

26.6.3.18 DES Key Setup (DESK)
The DESK command performs the initial key transformation (permuted choice 1) defined
by the DES algorithm on CA0 and CA1 with CA0 containing bits 1–32 of the key and
CA1 containing bits 33–64 of the key
and the values C
set for decrypt operations. If the DC bit is not set, a left shift by one also occurs and the
values C
for encrypt operations. If the CP bit is set and a key parity error is detected, CASR[DPE]
bit is set; otherwise, it is cleared.
26.6.3.19 Hash Function (HASH)
The HASH command performs a hashing operation on a set of registers and adds that
result to the value in CAA and stores the result in CAA. The specific hash function
performed is based on the HFx field as defined in this table.
This table uses the following terms:
Freescale Semiconductor, Inc.
1. The DES algorithm numbers the most significant bit of a block as bit 1 and the least significant as bit 64.
HFx Code
• ROTR
• SHR
0
1
cp0ld.l
cp0ld.l
KSx Code
2
3
1
n
(CAx): shift CAx register right n times
and D
n
(CAx): rotate CAx register right n times
Define
HFG
HFF
HFx
#DESK+{CP}+{DC}
#HASH+HFx
1
0
store back to CA0 and CA1 respectively. The DC bit should be cleared
and D
Table 26-18. Key Shift Function Codes (continued)
0
MCF51JF128 Reference Manual, Rev. 2, 03/2011
store back to CA0 and CA1 respectively. The DC bit should be
Table 26-19. Hash Function Codes
Define
KSR1
KSR2
KSx
Hash Function
Table continues on the next page...
MD5 G()
MD5 F()
1
. If the DC bit is set, no shift operation performs
Preliminary
Chapter 26 Cryptographic Acceleration Unit (CAU)
(CA1 & CA2) | (CA1 & CA3)
(CA1 & CA3) | (CA2 & CA3)
Shift Function
Right 1
Right 2
Hash Logic
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