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5.3.5. MAC Dropping on Decryption
To enable this feature, set the decrypt_drop_mac_en parameter to 1. This feature is independent to ICV comparison feature where the ICV comparison result sent out to user is unaffected by this feature.
| Profile | MACsec | MACsec | MACsec | MACsec | MACsec | |||
|---|---|---|---|---|---|---|---|---|
| MAC_IV_tweak_en | 0 | 1 | 1 | 1 | 1 | |||
| data_en | 1 | 0 | 1 | 1 | 1 | |||
| next_packet_en | 0 | 1 | 1 | 1 | 0 | |||
| tlast | 0 | 1 | 1 | 1 | 1 | |||
| num_empty_bytes | 0 | 64 | 48 to 63 | 32 to 63 | 16 to 63 | |||
| DATA | ||||||||
| data[127:0] | AAD/Text | MAC | AAD/Text | AAD/Text | AAD/Text | |||
| data[255:128] | AAD/Text | AAD/Text | MAC | AAD/Text | AAD/Text | |||
| data[391:256] | AAD/Text | AAD/Text | AAD/Text | MAC | AAD/Text | |||
| data[511:392] | AAD/Text | AAD/Text | AAD/Text | AAD/Text | MAC | |||
| Profile | MACsec | MACsec | MACsec | MACsec | MACsec | |||
|---|---|---|---|---|---|---|---|---|
| tvalid | 1 | 1 | 1 | 1 | 1 | |||
| MAC_IV_tweak_en | 0 | 1 | 1 | 1 | 1 | |||
| data_en | 1 | 0 | 1 | 1 | 1 | |||
| next_packet_en | 0 | 1 | 1 | 1 | 0 | |||
| tlast | 1 | 0 | 1 | 1 | 1 | |||
| tkeep | All 1's | 1111_1111 1111_1111 1111_1111 1111_1111 1111_1111 1111_1111 0000_0000 0000_0000 |
1111_1111 1111_1111 1111_1111 1111_1111 0000_0000 0000_0000 1111_1111 1111_1111 |
1111_1111 1111_1111 0000_0000 0000_0000 1111_1111 1111_1111 1111_1111 1111_1111 |
0000_0000 0000_0000 1111_1111 1111_1111 1111_1111 1111_1111 1111_1111 1111_1111 |
|||
| tuser_last_segment0 | 0 | 0 | 1 | 0 | 0 | |||
| tuser_last_segment1 | 0 | 0 | 0 | 1 | 0 | |||
| tuser_last_segment2 | 0 | 0 | 0 | 0 | 1 | |||
| tuser_last_segment3 | 1 | 0 | 0 | 0 | 0 | |||
| DATA | ||||||||
| data[127:0] | AAD/Text | IDLE | AAD/Text | AAD/Text | AAD/Text | |||
| data[255:128] | AAD/Text | AAD/Text | IDLE | AAD/Text | AAD/Text | |||
| data[391:256] | AAD/Text | AAD/Text | AAD/Text | IDLE | AAD/Text | |||
| data[511:392] | AAD/Text | AAD/Text | AAD/Text | AAD/Text | IDLE | |||
If MAC is located in segment 0 and there is no subsequent packets in segment 1, 2, or 3, the tvalid signal deasserts since all segments are the IDLE bytes after the MAC dropping.