diff --git a/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/BaseWallet.kt b/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/BaseWallet.kt
index e21d2ec..e8bfaf5 100644
--- a/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/BaseWallet.kt
+++ b/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/BaseWallet.kt
@@ -43,7 +43,7 @@ interface Wallet {
 }
 
 sealed class BaseWallet(
-    mnemonic: String,
+    mnemonic: String?,
     hdPath: Array<Slip10RawIndex> = makeSecretNetworkPath(0.toUInt()),
     bech32Prefix: String = "secret"
 ) : Wallet {
@@ -53,7 +53,11 @@ sealed class BaseWallet(
     protected var address: String
 
     init {
-        val seed = Mnemonics.MnemonicCode(mnemonic).toSeed().toUByteArray()
+        val seed = if (mnemonic != null) {
+            Mnemonics.MnemonicCode(mnemonic).toSeed().toUByteArray()
+        } else {
+            Mnemonics.MnemonicCode(Mnemonics.WordCount.COUNT_12).toSeed().toUByteArray()
+        }
         val result = Slip10.derivePath(Slip10Curve.Secp256k1, seed, hdPath)
         privkey = result.privkey
         val uncompressed = Secp256k1.makeKeypair(privkey).pubkey
diff --git a/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/DirectSigningWallet.kt b/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/DirectSigningWallet.kt
index 894c352..25e1ad0 100644
--- a/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/DirectSigningWallet.kt
+++ b/secretk/src/commonMain/kotlin/io/eqoty/secretk/wallet/DirectSigningWallet.kt
@@ -7,8 +7,12 @@ import kotlinx.serialization.protobuf.ProtoBuf
 
 
 class DirectSigningWallet(
-    mnemonic: String,
+    mnemonic: String?,
 ) : BaseWallet(mnemonic) {
+
+    // helper constructor for swift
+    constructor() : this(null)
+
     override suspend fun getSignMode(): SignMode? = null
 
     fun signDirect(address: String, signDoc: SignDocProto): SignResponse {