Разработка системы academic credentials на блокчейне

Разработка системы academic credentials на блокчейне

Academic credentials — это не только диплом. Это микросертификаты, badge-и, подтверждения участия в конференциях, специализации, профессиональные лицензии. Система должна поддерживать весь этот спектр и быть совместима с международными стандартами — прежде всего W3C Verifiable Credentials и IMS Open Badges 3.0.

ERC-1155 для credential портфолио

В отличие от диплома (один документ), credential портфолио — коллекция badge-ей разных типов. ERC-1155 multi-token стандарт подходит лучше чем ERC-721: один контракт обслуживает все типы credentials, batch transfer для выдачи нескольких badge-ей одновременно.

contract AcademicCredentials is ERC1155, AccessControl {
    bytes32 public constant ISSUER_ROLE = keccak256("ISSUER_ROLE");
    
    struct CredentialType {
        string name;
        string description;
        string category;        // "DEGREE", "CERTIFICATE", "BADGE", "MICROCREDENTIAL"
        uint256 totalIssued;
        bool active;
    }
    
    // tokenId => CredentialType
    mapping(uint256 => CredentialType) public credentialTypes;
    
    // tokenId => recipient => metadata (исключает дупликаты)
    mapping(uint256 => mapping(address => bytes32)) public credentialMetadata;
    
    // SBT: запрет передачи credentials
    function safeTransferFrom(address, address, uint256, uint256, bytes memory)
        public pure override 
    {
        revert("Credentials are non-transferable");
    }
    
    function safeBatchTransferFrom(address, address, uint256[] memory, uint256[] memory, bytes memory)
        public pure override 
    {
        revert("Credentials are non-transferable");
    }
    
    function issueCredential(
        address recipient,
        uint256 credentialTypeId,
        bytes32 metadataHash
    ) external onlyRole(ISSUER_ROLE) {
        require(credentialTypes[credentialTypeId].active, "Credential type inactive");
        require(credentialMetadata[credentialTypeId][recipient] == 0, "Already issued");
        
        _mint(recipient, credentialTypeId, 1, "");
        credentialMetadata[credentialTypeId][recipient] = metadataHash;
        credentialTypes[credentialTypeId].totalIssued++;
        
        emit CredentialIssued(recipient, credentialTypeId, metadataHash);
    }
    
    // Batch выдача нескольких типов credentials одному получателю
    function batchIssueCredentials(
        address recipient,
        uint256[] calldata credentialTypeIds,
        bytes32[] calldata metadataHashes
    ) external onlyRole(ISSUER_ROLE) {
        uint256[] memory amounts = new uint256[](credentialTypeIds.length);
        for (uint i = 0; i < credentialTypeIds.length; i++) {
            amounts[i] = 1;
        }
        _mintBatch(recipient, credentialTypeIds, amounts, "");
    }
}

Metadata стандарт

IPFS metadata для каждого credential по Open Badges 3.0 схеме:

{
  "@context": ["https://www.w3.org/2018/credentials/v1", "https://w3id.org/openbadges/v3"],
  "type": ["VerifiableCredential", "OpenBadgeCredential"],
  "name": "Advanced Solidity Developer",
  "description": "Completion of Advanced Solidity course with score ≥ 85%",
  "image": "ipfs://QmBadgeImage...",
  "criteria": {
    "narrative": "Complete all modules, pass final exam with score ≥ 85%"
  },
  "credentialSubject": {
    "achievement": {
      "achievementType": "Certificate",
      "creator": { "id": "did:ethr:0xIssuerAddress", "name": "Blockchain Academy" },
      "name": "Advanced Solidity Developer"
    }
  },
  "issuanceDate": "2024-01-15T10:00:00Z"
}

Верификация работодателем

Упрощённый flow для HR:

async function verifyCredentialPortfolio(
  candidateAddress: string,
  requiredCredentials: string[]
): Promise<PortfolioVerification> {
  
  const tokenIds = await Promise.all(
    requiredCredentials.map(name => getTokenIdByName(name))
  );
  
  const balances = await credentialsContract.balanceOfBatch(
    tokenIds.map(() => candidateAddress),
    tokenIds
  );
  
  const verifiedCredentials = await Promise.all(
    tokenIds.map(async (tokenId, index) => {
      if (balances[index].eq(0)) return { name: requiredCredentials[index], valid: false };
      
      const metadataHash = await credentialsContract.credentialMetadata(tokenId, candidateAddress);
      const metadata = await fetchFromIPFS(metadataHash);
      
      return {
        name: requiredCredentials[index],
        valid: true,
        issuedAt: metadata.issuanceDate,
        issuer: metadata.credentialSubject?.achievement?.creator?.name,
      };
    })
  );
  
  return {
    candidateAddress,
    verifiedCredentials,
    allRequirementsMet: verifiedCredentials.every(c => c.valid),
  };
}

Система academic credentials с ERC-1155, Open Badges 3.0 metadata и HR верификационным порталом — 4-6 недель разработки. Добавление W3C VC подписей и DID интеграции — ещё 2-3 недели.