Mdeu Key Size Register (Mdeuksr); Mdeu Data Size Register (Mdeudsr) - Freescale Semiconductor MPC8313E Family Reference Manual

Security Engine (SEC) 2.2
Table 14-20. Mode Register—HMAC Generated Across a Sequence of Descriptors
All descriptors other than the final descriptor must output the intermediate message digest for the next
descriptor to reload as MDEU context.
SSL-MAC operations cannot be spread across a sequence of descriptors.
Additional information on descriptors can be found in
14.4.2.3

MDEU Key Size Register (MDEUKSR)

The MDEU key size register (MDEUKSR), shown in
memory that should be used in HMAC generation. The MDEU supports at most 64 bytes of key. The
MDEU will generate a key size error if the value written to the MDEUKSR exceeds 64 bytes.
0
Field
Reset
R/W
Addr
14.4.2.4

MDEU Data Size Register (MDEUDSR)

The MDEU data size register (MDEUDSR), shown in
to be processed. The MDEU decrements this number as it processes data. A read of this register provides
a snapshot of how much data remains to be processed.
The Data Size field is a 21-bit signed number. Values written to this register are added to the current
register value. Multiple writes are allowed. The MDEU processes data when there is a positive value in
this register and there is data available in the private MDEU input FIFO. (Negative values can arise in
inbound processing, when it is necessary to hold back data from the MDEU until the pad length has been
decrypted.)
Since the MDEU does not support bit offsets, bits 61–63 must be written as 0. Furthermore, when the
CONT bit of the MDEU mode register (MDEUMR) is high, the data size must be a multiple of the 512-bit
block size (that is, bits 55–63 must be written as 0). Violating either of these conditions causes a data size
error (DSE in the MDEUISR).
MPC8313E PowerQUICC II Pro Integrated Processor Family Reference Manual, Rev. 3
14-32
Bits Field
Descriptor
56 CONT
59 INIT
60 HMAC
—
Figure 14-17. MDEU Key Size Register (MDEUKSR)
Value
First Middle
Descriptor(s)
1 (on) 1 (on)
1 (on) 0 (off)
1 (on) 0 (off)
Section 14.3, "Descriptor Overview."
Figure 14-17, indicates the number of bytes of key
0
R/W
MDEU 0x3_6008
Figure 14-18, indicates the number of bits of data
Final
Descriptor
0 (off)
0 (off)
1 (on)
56 57
Key Size (bytes)
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