37.8.12 Galois Hash n (GCM mode only)

Name: GHASHn
Offset: 0x6C + n*0x04 [n=0..3]
Reset: 0x00000000
Property: PAC Write-Protection

Bit 3130292827262524 
 GHASH[31:24] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 2322212019181716 
 GHASH[23:16] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 15141312111098 
 GHASH[15:8] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 76543210 
 GHASH[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bits 31:0 – GHASH[31:0] Galois Hash Value

The four 32-bit Hash Word registers GHASHx contain the GHASH value after GF128 multiplication in GCM mode. Writing a new key to KEYWORDx registers causes GHASH to be initialized with zeroes. These registers can also be programmed.