Digi NS9215 - Manual (Page 360)

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
CBC, CFB, OFB, and CTR processing
360 Hardware Reference NS9215
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C B C , C F B , O F B , a n d C T R p r o c e s s i n g
CBC, CFB, OFB, and CTR modes need an initialization vector. Software must set up
this buffer descriptor sequence: Key, IV, Data.
Processing flow
diagram
This is the buffer descriptor processing flow for CBC, CFB, OFB, and CTR:
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C C M m o d e
CCM mode does not require an initialization vector.
Key Buffer
Data Buffer
Destination DMA
Operations
ECB Mode
Encryption / Decryption
Source DMA
Operations
Encrypted or
Decrypted Data
Key Buffer
IV
Source DMA
Operations
Destination DMA
Operations
CBC , CFB , OFB , and CTR Mode
Encryption / Decryption
Data Buffer
Encrypted or
Decrypted Data