Field Name
Description
Bits
Default
ENC_CM
Encryption Count Mode.
If this bit is set to zero, the encryption source
count in the 820x begins to decrement after the last
header byte has been passed through the 820x. If
this bit is set to one, the encryption source counter
begins to decrement after the last byte processed
by the previous processing engine. Please refer to
Section 3.1.3.10, “IPsec Packet Processing" for
more information.
5
0
0
0
820x begins to decrement the encryption
source count after the last header byte
1
820x begins to decrement the encryption
source count after the last byte processed by
the previous processing engine
Reserved
4
Reserved.
ENC_AG[3:0]
Encryption Algorithm.
0000AES-GCM
Hash engine should be set to AES-GCM-MAC
algorithm
0001AES-CBC
0010AES-CTR
0011AES-ECB
0100AES-XTS
3:0
0
Compression Engine must be disabled and
Hash_OP[1:0] cannot be set any type of
MAC operation
01013DES
All other settings are reserved.
Note: GMAC operations use the AES algorithm. If
sharing logic with other AES modes, the GMAC will
be implemented in the Encryption Engine.
3.1.2.5
Desc_cmd_hash
This descriptor defines the hash engine related parameters. Desc_cmd_hash is 8 bytes for
either 32-bit or 64-bit addressing modes.
During a Slice Hash operation, the Hash engine will calculate the hash value for every slice
of data. A single Slice Hash operation must contain more than one slice. The size of one
slice data is defined by Slice_Size[15:0].
During a File Hash operation, the Hash engine calculates one hash value for the entire file.
File Hash operations may be stateless or stateful. For a stateless file hash operation, one
command operates on data from one file and the “file hash chaining value” of this
command is the “File Hash” of the file (see Section 3.1.3.6). For a stateful file hash
operation, one data file is operated on by several commands, and each command is
assigned a file hash chaining value by the 820x. The file hash chaining value of the prior
final command is used as the “File hash” of the file.
820x – Data Sheet, DS-0157-D
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