core: export the secret of a single name key

/_wallet export gives the seed mnemonic, /_wallet export <account> <name>
gives the secret of one derived key, so a single name can be handed over
without the seed. Both are what a wallet takes on import: the mnemonic as a
recovery phrase, the secret as hex.

The commands are named for what they return, APIWalletExportSeedMnemonic
and APIWalletExportDerivedSecret, as the difference is which secret leaves
the device.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Rvc3HbiWBTqbAvRT45G5oX

src/Simplex/Chat/Controller.hs

@@ -68,7 +68,7 @@ import Simplex.Chat.Types
 import Simplex.Chat.Types.Preferences
 import Simplex.Chat.Types.Shared
 import Simplex.Chat.Types.UITheme
-import Simplex.Chat.Wallet (AccountIndex)
+import Simplex.Chat.Wallet (AccountIndex, NameIndex)
 import Simplex.Chat.Util (liftIOEither)
 import Simplex.FileTransfer.Description (FileDescriptionURI)
 import Simplex.Messaging.Server.Information (ServerPublicInfo)
@@ -420,7 +420,8 @@ data ChatCommand
   | APIWallet
   | APIWalletCreate
   | APIWalletImport {recoveryPhrase :: Text}
-  | APIWalletExport
+  | APIWalletExportSeedMnemonic
+  | APIWalletExportDerivedSecret {accountIndex :: AccountIndex, nameIndex :: NameIndex}
   | APIWalletDelete
   | APISendCallInvitation ContactId CallType
   | SendCallInvitation ContactName CallType
@@ -750,7 +751,8 @@ allowRemoteCommand = \case
   APIWallet -> False
   APIWalletCreate -> False
   APIWalletImport _ -> False
-  APIWalletExport -> False
+  APIWalletExportSeedMnemonic -> False
+  APIWalletExportDerivedSecret {} -> False
   APIWalletDelete -> False
   _ -> True
 
@@ -854,7 +856,8 @@ data ChatResponse
   | CRServiceResponse {user :: User, responseData :: J.Object}
   | CRServiceReplyAccepted {user :: User, connectionId :: AgentConnId}
   | CRWallet {user :: User, walletKeyExists :: Bool, walletAccounts :: [(Text, AccountIndex, Bool, [(Text, Text)])]}
-  | CRWalletPhrase {user :: User, recoveryPhrase :: Text}
+  | CRWalletSeedMnemonic {user :: User, recoveryPhrase :: Text}
+  | CRWalletDerivedSecret {user :: User, keyPath :: Text, address :: Text, derivedSecret :: Text}
   | CRUserAcceptedGroupSent {user :: User, groupInfo :: GroupInfo, hostContact :: Maybe Contact}
   | CRUserDeletedMembers {user :: User, groupInfo :: GroupInfo, members :: [GroupMember], withMessages :: Bool, msgSigned :: Bool}
   | CRGroupsList {user :: User, groups :: [GroupInfo]}

src/Simplex/Chat/Library/Commands.hs

@@ -59,7 +59,7 @@ import Simplex.Chat.Library.Subscriber
 import Simplex.Chat.Badges (BadgeCredential (..), LocalBadge (..), badgeServerCredential, maxXFTPFileSize, mkBadgeStatus, verifyCredential)
 import Simplex.Chat.Names (SimplexDomainProof (..), SimplexDomainClaim (..), claimDomain, mkDomainClaim)
 import Simplex.Chat.Store.Wallets (deleteSeed, getDeviceSeed, getOrCreateAccountRef, getSeedAccounts, importSeed)
-import Simplex.Chat.Wallet (NameIndex, WalletSeed (..), accountAddress, deriveNameKey, importRecoveryKey, newSeed, recoveryKeyPhrase, renderNameKeyPath)
+import Simplex.Chat.Wallet (NameIndex, WalletSeed (..), accountAddress, accountSecret, deriveNameKey, importRecoveryKey, newSeed, recoveryKeyPhrase, renderNameKeyPath)
 import Simplex.Chat.Call
 import Simplex.Chat.Controller
 import Simplex.Chat.Delivery (DeliveryJobScope (..), DeliveryJobSpec (..), DeliveryWorkerScope (..))
@@ -1515,10 +1515,14 @@ processChatCommand cxt nm = \case
     r <- withFastStore' $ \db -> importSeed db user entropy
     when (isNothing r) $ throwCmdError "this device already has a wallet key"
     processChatCommand cxt nm APIWallet
-  APIWalletExport -> withUser $ \user -> do
+  APIWalletExportSeedMnemonic -> withUser $ \user -> do
     seed <- withFastStore' getDeviceSeed >>= maybe (throwCmdError noKeyError) pure
     phrase <- either (throwCmdError . ("wallet: " <>)) pure $ recoveryKeyPhrase seed
-    pure $ CRWalletPhrase user (safeDecodeUtf8 phrase)
+    pure $ CRWalletSeedMnemonic user (safeDecodeUtf8 phrase)
+  APIWalletExportDerivedSecret acct nameIdx -> withUser $ \user -> do
+    seed <- withFastStore' getDeviceSeed >>= maybe (throwCmdError noKeyError) pure
+    acc <- either (throwCmdError . ("wallet: " <>)) pure $ deriveNameKey seed acct nameIdx
+    pure $ CRWalletDerivedSecret user (renderNameKeyPath acct nameIdx) (tshow $ accountAddress acc) (safeDecodeUtf8 $ accountSecret acc)
   APIWalletDelete -> withUser $ \_ -> do
     seed <- withFastStore' getDeviceSeed >>= maybe (throwCmdError noKeyError) pure
     withFastStore' $ \db -> deleteSeed db (wsId seed)
@@ -5586,7 +5590,8 @@ chatCommandP =
       "/_service_response " *> (APISendServiceResponse <$> A.decimal <* A.space <*> strP <* A.space <*> jsonP),
       "/_wallet create" $> APIWalletCreate,
       "/_wallet import " *> (APIWalletImport <$> textP),
-      "/_wallet export" $> APIWalletExport,
+      "/_wallet export " *> (APIWalletExportDerivedSecret <$> A.decimal <* A.space <*> A.decimal),
+      "/_wallet export" $> APIWalletExportSeedMnemonic,
       "/_wallet delete" $> APIWalletDelete,
       "/_wallet" $> APIWallet,
       "/_call invite @" *> (APISendCallInvitation <$> A.decimal <* A.space <*> jsonP),

src/Simplex/Chat/View.hs

@@ -199,7 +199,8 @@ chatResponseToView hu cfg@ChatConfig {logLevel, showReactions, showFullLinks, te
         plain ("account " <> tshow acct <> " (" <> n <> (if active then ", active" else "") <> ")")
           : zipWith nameRow [0 :: Int ..] keys
       nameRow k (path, addr) = plain $ "  name " <> tshow k <> "  " <> path <> "  " <> addr
-  CRWalletPhrase u phrase -> ttyUser u [plain phrase]
+  CRWalletSeedMnemonic u phrase -> ttyUser u [plain phrase]
+  CRWalletDerivedSecret u path addr secret -> ttyUser u [plain $ path <> "  " <> addr <> "  " <> secret]
   CRGroupCreated u g -> ttyUser u $ viewGroupCreated g testView
   CRPublicGroupCreated u g _groupLink _relays -> ttyUser u $ viewGroupCreated g testView
   CRPublicGroupCreationFailed u results -> ttyUser u $ viewPublicGroupCreationFailed results

src/Simplex/Chat/Wallet.hs

@@ -17,11 +17,13 @@ module Simplex.Chat.Wallet
     deriveNameKey,
     renderNameKeyPath,
     accountAddress,
+    accountSecret,
   )
 where
 
 import Control.Concurrent.STM
 import Crypto.Random (ChaChaDRG)
+import qualified Data.ByteArray.Encoding as BAE
 import Data.ByteString (ByteString)
 import Data.Int (Int64)
 import Data.Text (Text)
@@ -91,3 +93,7 @@ deriveNameKey s acc nm = do
 
 accountAddress :: WalletAccount -> Address
 accountAddress = addressFromPrivateKey . waKey
+
+-- | Hex, as wallets take it when a key is imported on its own.
+accountSecret :: WalletAccount -> ByteString
+accountSecret a = "0x" <> BAE.convertToBase BAE.Base16 (S.unPrivateKey $ waKey a)