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Session creation

High level flow of DuoSession

DuoSession is the main object which will be used to perform all of the MPC operations supported. To create DuoSession please follow the steps below.

Step 1 : Add library to your Project

Step 2 : Create new session

  1. Provide websocket client by using any of the below options :
  2. Provide cloud/server public key.
  3. Provide storage client. (You need to implement the interface StorageClient).
  4. Provide Message Signer (You need to implement the interface MessageSigner).

Example

MainActivity.kt
import com.silencelaboratories.silentshard.duo.DuoSession
import com.silencelaboratories.silentshard.duo.SilentShard
import com.silencelaboratories.silentshard.network.websocket.WebsocketConfig
import com.silencelaboratories.silentshard.storage.KeyType
import com.silencelaboratories.silentshard.storage.StorageClient
import com.silencelaboratories.silentshard.storage.StorageDao
import com.silencelaboratories.silentshard.storage.silentshard.ReconcileStoreDao
import com.silencelaboratories.silentshard.utils.MessageSigner


object Constants {
    // Replace with your own
    const val CLOUD_NODE_URI = "demo-server.silencelaboratories.com"
    // Replace with your own
    const val PORT = 443
}

// Other party verifying-key/public-key. Replace with your own Verifying Key.
val cloudPublicKey = "cfa1ff5424d14eb60614d7ddf65a32243d26ddf7000d10007853d7336395efe4"

// Create websocketConfig to let SilentShard use the default WebsocketClient.
val websocketConfig = WebsocketConfig(url = Constants.CLOUD_NODE_URI, port = Constants.PORT, isSecure = true)

// Create a storageClient to persist keyshares. The SDK owns keyshare storage and
// addresses every share by its keyId — your code never holds raw keyshare bytes.
val storageClient = object : StorageClient {
    // The algorithm family this client stores keyshares for. Provide a separate
    // client (with a matching keyType) per algorithm if you run more than one.
    override val keyType = KeyType.ECDSA

    /**
     * An in-memory database. In the real world this should be a SQL-based DB,
     * secure storage, or custom hardware — it is up to the implementing app.
     */
    private val entries = mutableMapOf<String, ReconcileStoreDao>()

    override suspend fun write(dao: StorageDao) {
        require(dao is ReconcileStoreDao) { "Expected ReconcileStoreDao" }
        // Persist the whole snapshot, including any null fields.
        entries[dao.keyId] = dao
    }

    override suspend fun read(key: String): StorageDao? = entries[key]
}

// Create a messageSigner backed by your secure key storage (TEE / Keystore).
val messageSigner = object : MessageSigner {
    override val verifyingKey: ByteArray
        get() = TODO("Public key of secure key (Secure Environment - TEE)")
    override val keyType: MessageSigner.KeyType
        get() = TODO("Type of secure key (Secure Environment - TEE)")

    override suspend fun sign(data: ByteArray): ByteArray {
        TODO("Sign data using secure key (Secure Environment - TEE) and return the signature")
    }
}

// For quick-start you can use the test message signer. Do not use it in production.
val testMessageSigner = SilentShard.ECDSA.TestMessageSigner

// Create a DuoSession for the ECDSA algorithm
val duoSession: DuoSession = SilentShard.ECDSA.duoInitiator(
    // pass your messageSigner instance in production; do not use testMessageSigner
    testMessageSigner, cloudPublicKey, websocketConfig, storageClient
)

// Or create a DuoSession with your own network client by extending DuoNetworkClient:
// val duoSession: DuoSession = SilentShard.ECDSA.duoInitiator(
//     testMessageSigner, cloudPublicKey, CustomDuoNetworkClient(), storageClient
// )
  • CLOUD_NODE_URI is the URI of the cloud node.
  • cloudPublicKey is the cloud verifying key (Ed25519 public key).
    • This public key is used to verify the server's signature on each message
    • See example here
  • SilentShard Provides API for creating MPC DuoSession (Two-Party) using ECDSA algorithm.
  • ECDSA Provides factory methods for creating MPC session using ECDSA algorithm.
  • DuoSession Represents a two-party computation session that lets you perform MPC operations using SilentShard protocol.

You have now successfully set up the session and are ready to start performing MPC actions! 🎉