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Wallet SDK

Quickstart

You need Android Studio or Xcode, the SDK zip, and a phone to run your app on. About an hour.

  1. Add the SDK to your project: in Android Studio, the Maven folder and the two libraries; in Xcode, Wallet.xcframework (Embed & Sign), -lsqlite3 and the compose-resources folder. Step by step: Install & versions.

  2. Create the SDK object once for the process: where credentials come from, and which verifiers to name as trusted.

    WalletSetup.kt
    package samples
    

    import com.wallet.Wallet
    import com.wallet.WalletSdk
    import com.wallet.config.IssuerConfig
    import com.wallet.config.TrustedVerifiers
    

    /** The SDK object for a wallet app. Create it once, when the app starts, and keep it. */
    object WalletSetup {
        fun create(signedReaderList: ByteArray): WalletSdk = Wallet.createWallet(
            // Where credentials come from: your OpenID4VCI issuer.
            issuer = IssuerConfig(
                baseUrl = "https://issuer.example.com",
                clientId = "my-wallet",
                redirectUri = "mywallet://callback",
            ),
            // The verifiers named on the consent sheet ("Verify is asking for…"); others show as unknown.
            trustedVerifiers = TrustedVerifiers(signedList = signedReaderList),
            // Document types you hold besides the built-in driving licence.
            credentialTypes = listOf(EmiratesIdType.type),
            // A check before sharing, e.g. the face check (see Prove it's you). Null: share on consent.
            shareGuard = null,
        )
    }
    

    /** Shared by the samples: the one SDK instance of the app. */
    object App {
        lateinit var sdk: WalletSdk
    }

    Every credential’s key is kept in the phone’s secure hardware (the Android Keystore or the Secure Enclave).

  3. Show the wallet screen. It is the whole holder UI: cards, details, presenting, scanning offers, permissions.

    WalletActivity.kt
    package samples
    

    import android.os.Bundle
    import androidx.activity.compose.setContent
    import androidx.compose.material3.MaterialTheme
    import androidx.fragment.app.FragmentActivity
    import com.wallet.ui.WalletBranding
    import com.wallet.ui.WalletScreen
    

    /** The whole wallet UI: the card list, details, presenting, and scanning credential offers. */
    class WalletActivity : FragmentActivity() {
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContent {
                MaterialTheme(typography = WalletBranding.typography) {
                    WalletScreen(App.sdk)
                }
            }
        }
    }

    Host it in a FragmentActivity.

  4. Describe your document types. The driving licence is built in. For anything else, a CredentialType gives every field a label, a format and an icon; the wallet, the consent sheet and a verifier’s result screen all use it.

    EmiratesIdType.kt
    package samples
    

    import com.wallet.model.AttributeKind
    import com.wallet.model.CredentialAttribute
    import com.wallet.model.CredentialNamespace
    import com.wallet.model.CredentialType
    

    /** A document type: labels, formats and icons for every field. The wallet and the verifier both use it. */
    object EmiratesIdType {
        val type = CredentialType(
            docType = "org.iso.23220.photoid.1",
            displayName = "Emirates ID",
            namespaces = listOf(
                CredentialNamespace(
                    "org.iso.23220.1",
                    listOf(
                        CredentialAttribute("family_name", "Family name", AttributeKind.Text, mandatory = true, icon = "PERSON"),
                        CredentialAttribute("given_name", "Given names", AttributeKind.Text, mandatory = true, icon = "PERSON"),
                        CredentialAttribute("birth_date", "Date of birth", AttributeKind.Date, icon = "TODAY"),
                        CredentialAttribute("sex", "Sex", AttributeKind.Sex),
                        CredentialAttribute("portrait", "Photo", AttributeKind.Picture, icon = "ACCOUNT_BOX"),
                        CredentialAttribute("expiry_date", "Expiry date", AttributeKind.Date, icon = "EVENT"),
                    ),
                ),
                CredentialNamespace(
                    "org.iso.23220.photoid.1",
                    listOf(CredentialAttribute("person_id", "ID number", AttributeKind.Text, mandatory = true, icon = "BADGE")),
                ),
            ),
        )
    }

    Kinds: Text, Date, DateTime, Picture, Boolean, Number, Sex. Card designs are drawing functions per document type, supplied through a brand pack; document types without one get a neutral card.

  5. Run it on a phone (Android Studio: Run ▶; Xcode: ⌘R): Bluetooth and the camera don’t work in emulators or simulators. Scan a credential offer from your issuer to receive a credential, then present it to the Verify app on a second phone, and open a Hello Mobile link on the same phone.

Next: Hold and show credentials.