polygonID SDK部分代码分析

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回到polygonID SDK project，在项目中，理论性的iden3和polygonID算法，在实际代码中，如何连接呢？本文接续上文 iden3和polygonID原理应用和实战，讲述具体代码，如何实现的。

算法1：生成最终的proof

从技术角度来看，一个身份包括三棵树：claims tree，revocation tree，roots of roots tree。

代码实现：

https://github.com/0xPolygonID/polygonid-flutter-sdk/blob/a552fc6b2430353b05c0c2ef3c17567704012a90/lib/iden3comm/domain/use_cases/generate_iden3comm_proof_use_case.dart

  1. 为生成proof，准备入参：
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// Prepare atomic query inputs 准备计算查询的入参
Uint8List res = await _proofRepository  
    .calculateAtomicQueryInputs(  
  id: didEntity.identifier,  // 用户 DID
  profileNonce: param.profileNonce,  // 用户个人资料随机数
  claimSubjectProfileNonce: param.claimSubjectProfileNonce,  // 用户声明主题资料随机数
  authClaim: authClaim,  // 用户授权声明
  incProof: incProof,  // 如上图中 用户Claims Tree Root
  nonRevProof: nonRevProof,  // 如上图中 用户Revocation Tree Root
  gistProof: gistProof,  // 如上图中 用户Roots Tree Toot
  treeState: treeState,  // 如上图中 用户Identity State
  challenge: param.challenge,  // 挑战，由Issuer生成，作为生成proof的一部分
  signature: signature,  // 用户针对challenge的签名
  claim: param.credential,  // 用户证书，其中包含的PII Data
  proofScopeRequest: param.request.toJson(),  
  circuitId: param.request.circuitId,  // 使用的电路ID
  config: config,  
)

其中部分参数的示例如下：

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{
  "genesisDID": "did:iden3:tT2t3b685r2dKsjo4MioyKeceFT4mQEYfDd69EY5Y",
  "profileNonce": "0",
  "authClaim": [
    "304427537360709784173770334266246861770",
    "0",
    "17640206035128972995519606214765283372613874593503528180869261482403155458945",
    "20634138280259599560273310290025659992320584624461316485434108770067472477956",
    "15930428023331155902",
    "0",
    "0",
    "0"
  ],
  "authClaimIncMtp": {
    "existence": true,
    "siblings": []
  },
  "authClaimNonRevMtp": {
    "existence": false,
    "siblings": []
  },
  "treeState": {
    "state": "18656147546666944484453899241916469544090258810192803949522794490493271005313",
    "claimsRoot": "9763429684850732628215303952870004997159843236039795272605841029866455670219",
    "revocationRoot": "0",
    "rootOfRoots": "0"
  },
  "gistProof": {
    "root": "4924303677736085224554833340748086265406229626627819375177261957522622163007",
    "proof": {
      "existence": false,
      "siblings": [],
      "node_aux": {
        "key": "24846663430375341177084327381366271031641225773947711007341346118923321345",
        "value": "6317996369756476782464660619835940615734517981889733696047139451453239145426"
      }
    }
  },
  "signature": "fccc15d7aed2bf4f5d7dbe55c81087970344d13e5d9f348e61965ac364f41d29b366b52bc0820c603877352054833da083f5595c29c881ccd8ee47aa639aa103",
  "challenge": "10"
}
  1. 生成证明：
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// Prove 生成最终证明，其中的步骤实际是在调用iden3的类库
return _proveUseCase  
    .execute(param: ProveParam(atomicQueryInputs, param.circuitData))
    .then((proof) {  
_stacktraceManager.addTrace("[GenerateIden3commProofUseCase] proof");  
logger().i("[GenerateProofUseCase] proof: $proof");

2.1 生成证明的具体过程：

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Future<ZKProofEntity> execute({required ProveParam param}) async {  
  try {  
    // Calculate witness  计算见证
    Uint8List wtnsBytes = await _proofRepository.calculateWitness(  
      param.circuitData,  
      param.inputs,  
    );  
    // Generate proof  生成证明
    ZKProofEntity zkProofEntity = await _proofRepository.prove(  
      param.circuitData,  
      wtnsBytes,  
    );  
    _stacktraceManager.addTrace("[ProveUseCase] proof");  
    logger().i("[ProveUseCase] proof: $zkProofEntity");  
    return zkProofEntity;  
  } 
}

算法2：稀疏默克尔树

代码接口如下

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abstract class SMTRepository {  
  Future<void> addLeaf(  
      {required NodeEntity leaf,  
      required TreeType type,  
      required String did,  
      required String privateKey});  
  
  Future<NodeEntity> getNode(  
      {required HashEntity hash,  
      required TreeType type,  
      required String did,  
      required String privateKey});  
  
  Future<void> addNode(  
      {required HashEntity hash,  
      required NodeEntity node,  
      required TreeType type,  
      required String did,  
      required String privateKey});  
  
  Future<HashEntity> getRoot(  
      {required TreeType type,  
      required String did,  
      required String privateKey});  
  
  Future<void> setRoot(  
      {required HashEntity root,  
      required TreeType type,  
      required String did,  
      required String privateKey});  
  
  Future<MTProofEntity> generateProof({  
    required HashEntity key,  
    required TreeType type,  
    required String did,  
    required String privateKey,  
  });  
  
  Future<void> createSMT({  
    required int maxLevels,  
    required TreeType type,  
    required String did,  
    required String privateKey,  
  });  
  
  Future<void> removeSMT({  
    required TreeType type,  
    required String did,  
    required String privateKey,  
  });  
  
  Future<String> hashState({  
    required String claims,  
    required String revocation,  
    required String roots,  
  });  
  
  Future<Map<String, dynamic>> convertState({required TreeStateEntity state});  
}

综上，polygonID 很好地在手机端（Flutter）和web端（JavaScript and TypeScript）实现了DID-Holder端SDK。