Credential Manager - Verifier API

Android 應用程式中的數位憑證驗證功能，可用於驗證及授權使用者身分 (例如政府核發的身分證件)、使用者相關屬性 (例如駕照、學位或年齡/地址等屬性)，或在其他情境中核發及驗證憑證，以確認實體的真實性。

數位憑證是 W3C 公開標準，用於指定如何從數位錢包存取使用者的可驗證數位憑證，並透過 W3C 憑證管理 API 實作，適用於網路應用情境。在 Android 裝置上，Credential Manager 的 DigitalCredential API 用於驗證數位憑證。

實作

如要在 Android 專案中驗證數位憑證，請按照下列步驟操作：

  1. 在應用程式的建構指令碼中加入依附元件，並初始化 CredentialManager 類別。
  2. 建構數位憑證要求，並用來初始化 DigitalCredentialOption，然後建構 GetCredentialRequest。
  3. 使用建構的要求啟動 getCredential 流程，即可接收成功的 GetCredentialResponse 或處理可能發生的任何例外狀況。成功擷取後，請驗證回應。

新增依附元件並初始化

將下列依附元件新增至 Gradle 建構指令碼：

dependencies {
    implementation("androidx.credentials:credentials:1.6.0-beta01")
    implementation("androidx.credentials:credentials-play-services-auth:1.6.0-beta01")
}

接著，初始化 CredentialManager 類別的執行個體。

val credentialManager = CredentialManager.create(context)

建構數位憑證要求

建構數位憑證要求，並用來初始化 DigitalCredentialOption。

// The request in the JSON format to conform with
// the JSON-ified Credential Manager - Verifier API request definition.
val requestJson = generateRequestFromServer()
val digitalCredentialOption =
    GetDigitalCredentialOption(requestJson = requestJson)

// Use the option from the previous step to build the `GetCredentialRequest`.
val getCredRequest = GetCredentialRequest(
    listOf(digitalCredentialOption)
)

以下是 OpenId4Vp 要求的範例。如需完整參考資料，請參閱這個網站。

{
  "requests": [
    {
      "protocol": "openid4vp-v1-unsigned",
      "data": {
        "response_type": "vp_token",
        "response_mode": "dc_api",
        "nonce": "OD8eP8BYfr0zyhgq4QCVEGN3m7C1Ht_No9H5fG5KJFk",
        "dcql_query": {
          "credentials": [
            {
              "id": "cred1",
              "format": "mso_mdoc",
              "meta": {
                "doctype_value": "org.iso.18013.5.1.mDL"
              },
              "claims": [
                {
                  "path": [
                    "org.iso.18013.5.1",
                    "family_name"
                  ]
                },
                {
                  "path": [
                    "org.iso.18013.5.1",
                    "given_name"
                  ]
                },
                {
                  "path": [
                    "org.iso.18013.5.1",
                    "age_over_21"
                  ]
                }
              ]
            }
          ]
        }
      }
    }
  ]
}

取得憑證

使用建構的要求啟動 getCredential 流程。如果要求成功，您會收到 GetCredentialResponse，如果要求失敗，則會收到 GetCredentialException。

getCredential 流程會觸發 Android 系統對話方塊，向使用者顯示可用的憑證選項，並收集使用者的選擇。接著，含有所選憑證選項的錢包應用程式會顯示 UI，收集同意聲明並執行產生數位憑證回應所需的動作。

coroutineScope.launch {
    try {
        val result = credentialManager.getCredential(
            context = activityContext,
            request = getCredRequest
        )
        verifyResult(result)
    } catch (e : GetCredentialException) {
        handleFailure(e)
    }
}

// Handle the successfully returned credential.
fun verifyResult(result: GetCredentialResponse) {
    val credential = result.credential
    when (credential) {
        is DigitalCredential -> {
            val responseJson = credential.credentialJson
            validateResponseOnServer(responseJson)
        }
        else -> {
            // Catch any unrecognized credential type here.
            Log.e(TAG, "Unexpected type of credential ${credential.type}")
        }
    }
}

// Handle failure.
fun handleFailure(e: GetCredentialException) {
  when (e) {
        is GetCredentialCancellationException -> {
            // The user intentionally canceled the operation and chose not
            // to share the credential.
        }
        is GetCredentialInterruptedException -> {
            // Retry-able error. Consider retrying the call.
        }
        is NoCredentialException -> {
            // No credential was available.
        }
        is CreateCredentialUnknownException -> {
            // An unknown, usually unexpected, error has occurred. Check the
            // message error for any additional debugging information.
        }
        is CreateCredentialCustomException -> {
            // You have encountered a custom error thrown by the wallet.
            // If you made the API call with a request object that's a
            // subclass of CreateCustomCredentialRequest using a 3rd-party SDK,
            // then you should check for any custom exception type constants
            // within that SDK to match with e.type. Otherwise, drop or log the
            // exception.
        }
        else -> Log.w(TAG, "Unexpected exception type ${e::class.java}")
    }
}