Partial SSL3.0-MAC Value for Stateful Operations
For a stateful SSL3.0-MAC operation, the host software should write the partial SSL3.0-MAC
value into the IHV field for all blocks except the first.
Because the IHV is not protected by a CRC, the 820x will transmit the IHV to the host
destination buffer if the DIR bit in the Desc_cmd_base is set to one. The host software can
then determine whether the IHV has been corrupted.
Figure 3-11. Partial IHV Field for a Stateful SSL3.0-MAC Operations
3.1.3.2
MAC
For encode operations, the host software configures the Hash Engine's position in the data
processing channel and builds the command structure according to the application’s
requirement. The Hash Engine calculates the MAC value of the input data stream. The 820x
writes the resulting MAC value to the first entry of the hash buffer.
For decode operations, the host software writes the MAC value into the proper location of
the source buffer. The 820x Channel Manager will separate the MAC value from the source
data stream and put it on the hash information bus (Please refer to Section 3.1.3.5, “Data
Stream Information Fields" for details). The Hash Engine calculates the MAC value of the
input data stream, compares it with the value in the information bus, and then reports the
verified value or failure flag to the host. For a stateful MAC operation, the host software
should also write the partial MAC value into the IHV field. The MAC value field in the first
source buffer is fixed to 256 bits (32 bytes) as shown in Figure 3-12 below.
Because the MAC is not protected by a CRC, the 820x will transmit the MAC to the host
destination buffer. The host software can then determine whether the MAC has been
corrupted.
820x – Data Sheet, DS-0157-D
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