Freescale Semiconductor MCF5480 - Manual (Page 708)

MCF548x Reference Manual, Rev. 3
22-106 Freescale Semiconductor
Table 22-111 lists several different descriptor header values that can be used for the outbound TLS
descriptor 1 shown in Table 22-110 .
At the conclusion of inbound TLS descriptor 2, the crypto-channel has calculated the HMAC, placed it in
memory, and has reset and released the MDEU. The host can compare the HMAC generated by inbound
descriptor 2 with the HMAC that was transmitted as part of the record. If the HMACs match, the record is
known to have arrived unmodified, and can be passed to the application layer.
PTR_1 Pointer (not used) NULL
LEN_2 IV Length NULL
PTR_2 IV Pointer NULL
LEN_3 Key Length Number of bytes of HMAC key
PTR_3 Key Pointer Pointer to HMAC key
LEN_4 Data In Length Number of bytes of data to be hashed
PTR_4 Data In Pointer Pointer to data to perform hash upon
LEN_5 Data Out Length NULL
PTR_5 Data Out Pointer NULL
LEN_6 IV Out Length Number of bytes of data after hashing (16, 20, or 32)
PTR_6 IV Out Pointer Pointer to location where hash output is to be written
LEN_7 MAC Out Length NULL
PTR_7 MAC Out Pointer NULL
PTR_NEXT Next Descriptor Pointer Null or pointer to unrelated next descriptor
Table 22-111. Typical Header Values for Outbound TLS Descriptor One Format
Header Value Algorithm HMAC Pad
0x31D00010 SHA256 Yes Yes
0x31E00010 MD5 Yes Yes
0x31C00010 SHA Yes Yes
Table 22-110. Inbound TLS Descriptor Two Format (Continued)
Field Name Value/Type Description