Comparative Experiments of V2X Security Protocol Based on Hash Chain Cryptography

. 2020 Oct 8;20(19):5719. doi: 10.3390/s20195719

Algorithm 1 Proposed Message Authentication Algorithm

Requirements: two vehicles

v_{i}

v_{j}

share a common hash-chain of n secret keys
Signing Algorithm:

v_{i}

pick a random secret key

k_{i}

from the pre-stored hash table.

v_{i}

calculates a MAC signature

(S i g_{k_{i}})

using HMAC-SHA256 with the key

k_{i}

over the message consisting of pseudo-identity

P I D_{i}

, the original payload

m_{i, j}

, and time-stamp

T_{s}

S i g_{k_{i}} = H M A C_S H A 256_{k_{i}} (P I D_{i} | | m_{i, j} | | T s

)

v_{i}

sends {

P I D_{i}, S i g_{k_{i}}, m_{i, j}, k_{i n d e x}, T_{s}

} to

v_{j}

.
Verifying Algorithm:

1.
$v_{j}$ receives { $P I D_{i}, S i g_{k i}, m_{i, j}, k_{i n d e x}, T_{s}$ }, then extract the $k_{i n d e x}$ , search the pre-stored hash table to find $k_{i}$ that match the received index.
2.
$v_{j}$ calculates a MAC signature

S i g_{k_{i}}^{*} = H M A C_S H A 256_{k_{i}} (P I D_{i} | | m_{i, j} | | T s)

3.
$v_{j}$ accepts the message if and only if $S i g_{k_{i}} = S i g_{k_{i}}^{*}$ , else discard the message.