Giters

imtypist / AAVBvanet

A Privacy-Preserving Vehicular Data Sharing Framework atop Multi-Sharding Blockchain, IEEE GLOBECOM'21.

Geek Repo:Geek Repo

Github PK Tool:Github PK Tool

AAVB: Anonymous yet Accountable VANET System atop Blockchain

Primitives

  • RA has a public-private key pair (mpk, msk)

  • A vehicle has a public-private key pair (pk, sk)

  • RA generates certificates for vehicles

CertGen(msk, pk) -> cert
  • RA generates proof.key and verification.key of zkSNARKs
KeyGen() ->  (proof.key, verification.key)
  • Vehicles prove message m and pseudo random address ppk
Auth(ppk||m, mpk, sk, pk, cert, proof.key) -> (ppk||m, mpk, pi=(t, η))

where t=Enc_mpk(pk||ppk||m), η is the zkSNARKs proof.

  • RSUs verify the proof
Verify(ppk||m, mpk, pi, verification.key) -> {0, 1}
  • RA can reveal the real identity of vehicles by decrypting t

Implementation and Experiments

source code

experiment setting

  • Here we used jsnark to implement zkSNARKs, according to the performance comparison of three classic zero knowledge proof (ZKP) algorithms provided in libsnark, we chose the better one Groth16 as our underlying ZKP technology.
  • The experiment setting is that using a virtual machine (VM) ubuntu14.04 running on VirtualBox, the number of VM's CPU core is 2, the size of memory is 4GB; The localhost CPU is Intel i7-7700, the size of memory is 16GB.
  • In this experiment, the implemented group signature scheme is BBS04 and the ring signature scheme is LSAG.

performance

zk-SNARK

The RSA key length is set to 2048 bits, which is safe enough currently.

VANETCircuitGenerator is the circuit generator code of VANET.

The output below is the testcase for VANET, the example input is a pseudo random address concatenating a piece of GPS raw data.

Running Circuit Generator for < vanet_rsa2048 >
Circuit Generation Done for < vanet_rsa2048 >  
 	 Total Number of Constraints :  414319

PlainText:0xd91c747b4a76B8013Aa336Cbc52FD95a7a9BD3D9$GPRMC,092927.000,A,2235.9058,N,11400.0518,E,0.000,74.11,151216,,D*49
Running Circuit Evaluator for < vanet_rsa2048 >
	[output] Value of Wire # 1277072 (Is Signature valid?) :: 1
	[output] Value of Wire # 2226921 (Output cipher text[0]) :: 1251022490261258172529308360859369551837157967434844421554503068336263232
	[output] Value of Wire # 2226922 (Output cipher text[1]) :: 782513615157148428896018740256285560893017553685924761331573477021861754
	[output] Value of Wire # 2226923 (Output cipher text[2]) :: 297893711879754138931627910652983846133902364790173190431445656834653104
	[output] Value of Wire # 2226924 (Output cipher text[3]) :: 1062246178463496446723238490343351688931627517611251013590768981856952089
	[output] Value of Wire # 2226925 (Output cipher text[4]) :: 283619758270485012554111906691482726594266063316848294719061553920244069
	[output] Value of Wire # 2226926 (Output cipher text[5]) :: 1605604628605955420311218435655442487833758868828180874969980792959738819
	[output] Value of Wire # 2226927 (Output cipher text[6]) :: 1765324337636077192622074629173695556494918446370154704523581054010828502
	[output] Value of Wire # 2226928 (Output cipher text[7]) :: 229242121535333726124694280674701732758091959395234671423966224579886508
	[output] Value of Wire # 2226929 (Output cipher text[8]) :: 41995595892867847343690929056587572862
Circuit Evaluation Done for < vanet_rsa2048 >

group/ring signature

Note that maximum ring size is hard coded as 32 in FISCO-BCOS/group-signature-server. Here I set it to 1024 for testing a larger ring size. You can change it by yourselves.

In this experiment result, I added the performance of revoke and update member private key operations. To achieve that, I implemented revoke_member and revoke_update_private_key RPC interfaces, which are not yet implemented in the original repository. If you want to use them directly, you can git clone from imtypist/group-signature-server.

About

A Privacy-Preserving Vehicular Data Sharing Framework atop Multi-Sharding Blockchain, IEEE GLOBECOM'21.