Updated on 2026-08-14

domain/visa/models/build.gradle.kts

@@ -15,4 +15,7 @@ dependencies {
 
     /** Domain models */
     implementation(projects.domain.models)
+
+    /** Tangem libraries (derived public keys types for VA activation) */
+    implementation(tangemDeps.card.core)
 }

domain/visa/models/src/main/kotlin/com/tangem/domain/visa/model/VirtualAccountActivationData.kt

@@ -0,0 +1,16 @@
+package com.tangem.domain.visa.model
+
+import com.tangem.common.extensions.ByteArrayKey
+import com.tangem.operations.derivation.ExtendedPublicKeysMap
+
+/**
+ * Result of deriving the Virtual Account key on the card.
+ *
+ * @property address     the VA deposit address generated from the derived key
+ * @property derivedKeys the derived extended public key(s) keyed by the seed wallet public key,
+ *                       ready to be persisted into the wallet (see `DerivationsRepository.storeDerivedKeys`)
+ */
+data class VirtualAccountActivationData(
+    val address: String,
+    val derivedKeys: Map<ByteArrayKey, ExtendedPublicKeysMap>,
+)

domain/visa/src/main/kotlin/com/tangem/domain/pay/datasource/TangemPayAuthDataSource.kt

@@ -4,11 +4,14 @@ import arrow.core.Either
 import com.tangem.domain.models.wallet.UserWallet
 import com.tangem.domain.pay.WithdrawalSignatureResult
 import com.tangem.domain.visa.model.TangemPayInitialCredentials
+import com.tangem.domain.visa.model.VirtualAccountActivationData
 
 interface TangemPayAuthDataSource {
 
     suspend fun produceInitialCredentials(userWallet: UserWallet): Either<Throwable, TangemPayInitialCredentials>
 
+    suspend fun produceVirtualAccountData(userWallet: UserWallet): Either<Throwable, VirtualAccountActivationData>
+
     suspend fun getWithdrawalSignature(
         userWallet: UserWallet,
         hash: String,

domain/visa/src/main/kotlin/com/tangem/domain/virtualaccount/repository/VirtualAccountActivationRepository.kt

@@ -0,0 +1,13 @@
+package com.tangem.domain.virtualaccount.repository
+
+import com.tangem.domain.models.wallet.UserWalletId
+
+interface VirtualAccountActivationRepository {
+
+    /**
+     * Derives the Virtual Account key on the card (NFC) and persists it into the wallet, so the
+     * on-chain VA balance can later be fetched without re-deriving. Throws on failure.
+     */
+    @Throws
+    suspend fun activateVirtualAccount(userWalletId: UserWalletId)
+}

domain/visa/src/main/kotlin/com/tangem/domain/virtualaccount/usecase/ActivateVirtualAccountUseCase.kt

@@ -0,0 +1,17 @@
+package com.tangem.domain.virtualaccount.usecase
+
+import arrow.core.Either
+import arrow.core.Either.Companion.catch
+import com.tangem.domain.models.wallet.UserWalletId
+import com.tangem.domain.virtualaccount.repository.VirtualAccountActivationRepository
+
+class ActivateVirtualAccountUseCase(
+    private val repository: VirtualAccountActivationRepository,
+) {
+
+    suspend operator fun invoke(userWalletId: UserWalletId): Either<Throwable, Unit> {
+        return catch {
+            repository.activateVirtualAccount(userWalletId)
+        }
+    }
+}

domain/wallets/src/main/java/com/tangem/domain/wallets/derivations/ColdMapDerivationsRepository.kt

@@ -27,6 +27,9 @@ interface ColdMapDerivationsRepository {
         derivations: Map<ByteArrayKey, List<DerivationPath>>,
     ): Pair<UserWallet.Cold, Map<ByteArrayKey, ExtendedPublicKeysMap>>
 
+    /** Merges already-derived [keys] into [userWallet]'s stored derivations without deriving on the card. */
+    fun mergeDerivedKeys(userWallet: UserWallet.Cold, keys: Map<ByteArrayKey, ExtendedPublicKeysMap>): UserWallet.Cold
+
     /** Check if user [userWallet] has missed derivations using map of [Network.ID] with extraDerivationPath */
     suspend fun hasMissedDerivations(
         userWallet: UserWallet.Cold,

domain/wallets/src/main/java/com/tangem/domain/wallets/derivations/DerivationsRepository.kt

@@ -29,6 +29,14 @@ interface DerivationsRepository {
         derivations: Map<ByteArrayKey, List<DerivationPath>>,
     ): Map<ByteArrayKey, ExtendedPublicKeysMap>
 
+    /**
+     * Merges already-derived [derivedKeys] into the wallet's stored derivations and persists it.
+     * Does NOT derive on the card (no NFC): use it to save a key that was obtained by a dedicated
+     * card task. Keyed by the seed wallet public key ([ByteArrayKey]).
+     */
+    @Throws
+    suspend fun storeDerivedKeys(userWalletId: UserWalletId, derivedKeys: Map<ByteArrayKey, ExtendedPublicKeysMap>)
+
     /** Returns already derived extended public keys for the given [seedKey] */
     suspend fun getExistingDerivedKeys(userWalletId: UserWalletId, seedKey: ByteArrayKey): ExtendedPublicKeysMap
 

domain/wallets/src/main/java/com/tangem/domain/wallets/derivations/HotMapDerivationsRepository.kt

@@ -29,6 +29,9 @@ interface HotMapDerivationsRepository {
         derivations: Map<ByteArrayKey, List<DerivationPath>>,
     ): Pair<UserWallet.Hot, Map<ByteArrayKey, ExtendedPublicKeysMap>>
 
+    /** Merges already-derived [keys] into [userWallet]'s stored derivations. */
+    fun mergeDerivedKeys(userWallet: UserWallet.Hot, keys: Map<ByteArrayKey, ExtendedPublicKeysMap>): UserWallet.Hot
+
     /** Check if user [userWallet] has missed derivations using map of [Network.ID] with extraDerivationPath */
     suspend fun hasMissedDerivations(
         userWallet: UserWallet.Hot,