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Identity State

An Identity State IdS is represented by the hash of the roots of these three merkle trees.

IdS = H(ClR || ReR || RoR) where:

  • H: Hashing Function
  • ClR: Claims Tree Root
  • ReR: Revocation Tree Root
  • RoR: Roots Tree Root

The identity state gets stored on-chain and represents the status of an identity at a certain point in time.

Identity State Diagram

Retrieve the Identity State IdS

package main

import (
    "fmt"
    "github.com/iden3/go-merkletree-sql"
)

// Retrieve Identity State
func main() {

    // calculate Identity State as a hash of the three roots
    state, _ := merkletree.HashElems(
        clt.Root().BigInt(),
        ret.Root().BigInt(),
        rot.Root().BigInt())

    fmt.Println("Identity State:", state)

}

Here is what the output would look like: 

Identity State: 
20698226269617404048572275736120991936409000313072409404791246779211976957795

The very first identity state of an identity is defined as Genesis State

Every verification inside Iden3 protocol is executed against the Identity State. For instance, to prove the validity of a specific claim issued by A to B (in case if the claims gets added to the claims tree):

  • user B needs to produce a merkle proof of the existence of that claim inside user's A ClR
  • user B needs to produce a merkle proof of non existence of the corresponding revocation nonce inside user's A ReT

The executable code can be found here