AES_KEYWRx

AES Key Word Register x

  0x20 + x*0x04 [x=0..7] 32 Write-only –   8 -1
Parent topic: Register Summary

AES Key Word Register x

Bit  31 30 29 28 27 26 25 24  
  KEYW[31:24]  
Access  W W W W W W W W  
Reset  0 0 0 0 0 0 0 0  
Bit  23 22 21 20 19 18 17 16  
  KEYW[23:16]  
Access  W W W W W W W W  
Reset  0 0 0 0 0 0 0 0  
Bit  15 14 13 12 11 10 9 8  
  KEYW[15:8]  
Access  W W W W W W W W  
Reset  0 0 0 0 0 0 0 0  
Bit  7 6 5 4 3 2 1 0  
  KEYW[7:0]  
Access  W W W W W W W W  
Reset  0 0 0 0 0 0 0 –  

Bits 31:0 – KEYW[31:0]: Key Word

Key Word

The four/six/eight 32-bit Key Word registers set the 128-bit/192-bit/256-bit cryptographic key used for AES encryption/decryption.

AES_KEYWR0 corresponds to the first word of the key and respectively AES_KEYWR3/AES_KEYWR5/AES_KEYWR7 to the last one.

Whenever a new key (AES_KEYWRx) is written to the hardware, two automatic actions are processed:
  • GCM hash subkey generation
  • AES_GHASHRx Clear

See Key Writing and Automatic Hash Subkey Calculation for details.

These registers are write-only to prevent the key from being read by another application.