A User Centric Security Model for Tamper-Resistant Devices

7.6 Application Binding Protocol Distributed
will then generate the session keys and long-term encryption and MAC keys in a similar
manner to that used in message three of PBP (see section 7.5.2).
ABPD-2. SE : h SE = h(SE i ||CL i ||SPi
CL ||SPi SE ||g r SE||g r CL||N CL ||N SE )
SE : cfs = Sign SE (CL i ||SE i ||h SE )
SE : mE = e KSE−CL (V R||ReqUserID||cfs||CertS SE )
SE → CL : g r SE||N SE ||mE||f mKSE−CL (mE)||DH GroupSel
The SE will generate a signature on the message containing the Die-Hellman exponential
generated by both the SE and CL, and their identities along with those of the respective
SP's concatenated with generated random numbers. The signed message is appended to the
SE's certicate along with a request for the CL's state validation and user authentication.
The user authentication is an optional parameter in the ABP D, which depends upon
whether a server application allows application sharing with client applications that are
issued to dierent users. If the SE allows application sharing with dierent user's CL then
the parameter can be omitted. Otherwise, ReqUserID will request the CL to provide the
details of the registered owner of the SCA. The message is then encrypted and MACed
using the session keys.
On receipt of message two (ABPD-2), the application CL will generate the session and
long-term encryption and MAC keys. After this, it will proceed with verifying the MAC
and decrypt message two. Subsequently, it will validate the certicate CertS SE and then
verify the signature.
ABPD-3. SCB : aub = Sign SCA (h(CL)||SCA i ||U i ||N CL ||N SE )
CL : h CL = h(CL i ||SE i ||g r CL||g r SE||N CL ||N SE )
CL : auc = Sign CL (CL i ||SE i ||h CL )
CL : mE = e KSE−CL (V R||aub||auc||CertS CL ||CertS SCB )
CL → SE : mE||f mKSE−CL (mE)
The CL will then ask the host smart card (SCA) to provide a validation proof. The
SCA will generate the hash of the application and then sign it. The signed message
also includes the identities of the smart card and its owner (if requested by the SE in
message two), and random numbers generated by both applications. In addition, the CL
generates a signature on the message containing Die-Hellman exponentials generated by
communicating applications along with the identities of their respective SPs and generated
random numbers. The signing of the message by the smart card provides security assurance
and validation of the client application, and the signing of the message by the client
application provides entity authentication to the server application.
After the server application SE receives message three, it will rst verify whether the
generated hash of the application is the same as that certied by either the SP of the SE
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