Networking and Multimedia Lab

Code Explain

• Under "./data", there are several owners, and each owner has two directories:
  1. localStorage is used to store "DID"
  2. TPM is used to store "DID-privateKey" and "vc"
• owner.py:
  1. create a new owner
  2. create directory
  3. create keypair, and save private one in TPM
  4. create did document, and save it in localStorage and blockchain
• item.py:
  1. create a new item
  2. create keypair, and save private one in TPM
  3. create did document, and save it in localStorage and blockchain
• vc.py:
  1. VC_transfer
  2. VC_revoke

How to execute?

1. go to directory pi@raspberrypi:~/nmlab/src
2. type python main.py

• The format of input statement:

1. if you want factory A to create a new item, please input createAnItem factory_A_did
2. if the ownership of item I is transfered from organization A to organization B and having an issuer C, please input transfer organization_A_did organization_B_did issuer_C_did item_I_did
3. if a gun is assembled by item 1, item 2, item 3 in the facory A and having an issuer C, please input assemble factory_A_did issuer_C_did item_I1_did item_I2_did item_I3_did
4. if the item I need to be revocated, please input revoke organization_A_did item_I_did

The discription of VC type:

1. transfer (A sells i to D):

   • holder: A
   • issuer: MOD
   • verifier: D
   • (issuer encrypt doc with own private key)
   • (holder decrypt doc with issuer's public key)
   • system generate the current time
   • holder "sign" vc with own private key
   • verifier "verify" vc with holder's public key
   • add vc(related to i)/private key from holder's TPM to verifier's TPM
   • remove i's DID from holder's localStorage

2. revoke (Army revokes i):

   • holder: Army
   • issuer: MOD
   • verifier: MOD
   • (issuer encrypt doc with own private key)
   • (holder decrypt doc with issuer's public key)
   • holder encrypt vc with own private key
   • verifier decrypt vc with holder's public key
   • remove vc(related to i)/private key from holder's TPM
   • remove i's DID from holder's localStorage# nmlab