IPv6 Tutorial - RIPE 64

IPv6 Security -Authentication• Sequence number• Unsigned 32-bit that is a monotonically increasing counter• Used to prevent replay attacks• Initialized to zero when the security association is established• Must never be allowed to cycle• Authentication data• Variable length field• Contains the Integrity Check Value (ICV) for the packet• What authentication algorithm used for the ICV is determined by the SA (DES, MD5, SHA-1, etc)• ICV is calculated over• IP header fields that does not change in transit or the value at the end point can be predicted• The AH• Upper layer data• What packets get an AH is determined by the SA (IPsec part of the stack)44