Digi NS9215 - Manual (Page 356)

A E S D A T A E N C R Y P T I O N / D E C R Y P T I O N M O D U L E
AES DMA buffer descriptor
356 Hardware Reference NS9215
Block diagram
Data blocks
The AES module works on 128-bit blocks of data. This table shows the performance
per each 128-bit block, depending on the key size:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A E S D M A b u f f e r d e s c r i p t o r
The AES DMA buffer descriptor is the same as the external DMA buffer descriptor,
with the exception of the control bits — AES op and AES control.
Ch 1 Ext DMA
Source
Key
Expander
FIFO
AES
Engine
FIFO
Expanded Key
Data In
Data Out
IV
Mode and Control
Ch 1 Ext DMA
Destination
From System Memory To System Memory
Key size
Characteristic 128 192 256
Number of cycles 44 52 60
Latency (cycles) 44 52 60
Throughput (bits/cycles) ~2.90 ~2.46 ~2.13
Throughput @ 75 MHz (bytes/sec) ~27.19 ~23.06 ~19.97