signcryptpub.vp

attacker [active]

// initialization process
principal KDS[
    generates parameters // generates security parameter
    params = G^parameters // publish params to the public
    knows private x // private key or secret key
    KDS_pub = G^x // The KDS computes its  public key
]

//Participants key generation process -> Each participant generates its private and public key pair
// NB:  The partipants  consists of doctor and the patient.
principal Patient[
    generates PID // Patient's identifier 
    knows private P // secret value
    Patient_pub = G^P  //  Patient's public key computation
]

Patient -> KDS : PID

principal Doctor[
    generates DID // Doctor's identifier 
    knows private D // secret value
    Doctor_pub = G^D //  Doctor's public key computation
]

Doctor -> KDS : DID

//Partial private key extraction process. KDS derives a partial private key for each participant
principal KDS[
 PKey = HASH(PID,x)  // construction of partial private key for Patient
 DKey = HASH(DID,x) // construction of partial private key for the doctor
]

KDS -> Patient:[PKey] // submit partial private key to Patient
KDS -> Doctor:[DKey] //  submit partial private key to Doctor

//Signcryption computation process
principal Patient[
    P_priv = CONCAT(PKey,P)//  Patient's full private key 
    P_pub = CONCAT(Pkey, PID, Patient_pub) // Patient's full public key 
    knows public symKey // generates symmetric  key
    generates timestamp// generates timestamp
   //ff = HASH(symKey,timestamp, P_pub) // hashes the symmetric key,timestamp and patient's public key.
   ff = HASH(symKey,timestamp) // hashes the symmetric key,timestamp and patient's public key.
    generates meddata // generates medical data
    medhash = HASH(meddata) // hashes the medical data. 
    Emeddata  = ENC(ff, medhash) // medical data encryption
    sig = SIGN(symKey,ENC(ff, medhash)) //signing  encrypted medical data
]
Patient -> Doctor : [ff], [medhash], [sig]

principal Doctor[
    D_priv = CONCAT(DKey,D)// full private key  of doctor
    D_pub = CONCAT(Dkey, DID, Doctor_pub) // full public key 
   Dmeddata= DEC(ff, ENC(ff, medhash)) //  medical data decryption
   sigvalidity = SIGNVERIF(symKey, medhash,sig) //verfies signature
]

// Query checking to determine if proposed protocol satisfies the necessary security requirements.
queries[
	confidentiality? meddata 
	freshness? ff
    freshness? Emeddata
    authentication? KDS -> Patient: [Pkey]
    authentication? KDS -> Doctor: [Dkey]
    authentication? Patient -> Doctor: [ff]
    authentication? Patient -> Doctor: [medhash]
    authentication? Patient -> Doctor: [sig]
    unlinkability? ff, Emeddata
]