MakePrisms · gudnuf · Sep 13, 2025
diff --git a/app/features/send/cashu-send-swap-hooks.ts b/app/features/send/cashu-send-swap-hooks.ts
@@ -8,7 +8,7 @@ import {
   useSuspenseQuery,
 } from '@tanstack/react-query';
 import { useEffect, useMemo, useState } from 'react';
-import type { SpendingConditionData } from '~/lib/cashu/types';
+import type { SpendingConditionData, UnlockingData } from '~/lib/cashu/types';
 import type { Money } from '~/lib/money';
 import { useSupabaseRealtimeSubscription } from '~/lib/supabase/supabase-realtime';
 import { useLatest } from '~/lib/use-latest';
@@ -137,11 +137,13 @@ export function useCreateCashuSendSwap({
       amount,
       accountId,
       spendingConditionData,
+      unlockingData,
       senderPaysFee = true,
     }: {
       amount: Money;
       accountId: string;
       spendingConditionData?: SpendingConditionData;
+      unlockingData?: UnlockingData;
       senderPaysFee?: boolean;
     }) => {
       const account = await getLatestCashuAccount(accountId);
@@ -151,6 +153,7 @@ export function useCreateCashuSendSwap({
         account,
         senderPaysFee,
         spendingConditionData,
+        unlockingData,
       });
     },
     onSuccess: (swap) => {

diff --git a/app/features/send/cashu-send-swap-repository.ts b/app/features/send/cashu-send-swap-repository.ts
@@ -3,6 +3,8 @@ import { sumProofs } from '~/lib/cashu';
 import {
   type SpendingConditionData,
   SpendingConditionDataSchema,
+  type UnlockingData,
+  UnlockingDataSchema,
 } from '~/lib/cashu/types';
 import { Money } from '~/lib/money';
 import {
@@ -94,6 +96,10 @@ type CreateSendSwap = {
    * The version seen by the client for optimistic concurrency control.
    */
   accountVersion: number;
+  /**
+   * The unlocking data to reverse the swap.
+   */
+  unlockingData?: UnlockingData;
 };
 
 export class CashuSendSwapRepository {
@@ -120,6 +126,7 @@ export class CashuSendSwapRepository {
       keysetCounter,
       outputAmounts,
       accountVersion,
+      unlockingData,
     }: CreateSendSwap,
     options?: Options,
   ) {
@@ -139,6 +146,7 @@ export class CashuSendSwapRepository {
       encryptedProofsToSend,
       encryptedTransactionDetails,
       encryptedSpendingConditionData,
+      encryptedUnlockingData,
     ] = await Promise.all([
       this.encryption.encrypt(inputProofs),
       this.encryption.encrypt(accountProofs),
@@ -147,6 +155,7 @@ export class CashuSendSwapRepository {
       spendingConditionData
         ? this.encryption.encrypt(spendingConditionData)
         : undefined,
+      unlockingData ? this.encryption.encrypt(unlockingData) : undefined,
     ]);
 
     const updatedKeysetCounter =
@@ -181,6 +190,7 @@ export class CashuSendSwapRepository {
       p_proofs_to_send: encryptedProofsToSend,
       p_token_hash: tokenHash,
       p_spending_condition_data: encryptedSpendingConditionData,
+      p_unlocking_data: encryptedUnlockingData,
     });
 
     if (options?.abortSignal) {
@@ -368,13 +378,16 @@ export class CashuSendSwapRepository {
     data: AgicashDbCashuSendSwap,
     decrypt: Encryption['decrypt'],
   ): Promise<CashuSendSwap> {
-    const [inputProofs, proofsToSend, spendingConditionData] =
+    const [inputProofs, proofsToSend, spendingConditionData, unlockingData] =
       await Promise.all([
         decrypt<Proof[]>(data.input_proofs),
         data.proofs_to_send ? decrypt<Proof[]>(data.proofs_to_send) : undefined,
         data.spending_condition_data
           ? decrypt<SpendingConditionData>(data.spending_condition_data)
           : undefined,
+        data.unlocking_data
+          ? decrypt<UnlockingData>(data.unlocking_data)
+          : undefined,
       ]);
 
     let validatedSpendingConditionData: SpendingConditionData | null = null;
@@ -393,6 +406,20 @@ export class CashuSendSwapRepository {
       validatedSpendingConditionData = validationResult.data;
     }
 
+    let validatedUnlockingData: UnlockingData | null = null;
+    if (unlockingData) {
+      const validationResult = UnlockingDataSchema.safeParse(unlockingData);
+      if (!validationResult.success) {
+        throw new Error('Invalid unlocking data', {
+          cause: {
+            data: unlockingData,
+            errors: validationResult.error.errors,
+          },
+        });
+      }
+      validatedUnlockingData = validationResult.data;
+    }
+
     const toMoney = (amount: number) => {
       return new Money({
         amount,
@@ -414,6 +441,7 @@ export class CashuSendSwapRepository {
       inputProofs,
       inputAmount: toMoney(data.input_amount),
       spendingConditionData: validatedSpendingConditionData,
+      unlockingData: validatedUnlockingData,
       currency: data.currency,
       version: data.version,
       state: data.state,

diff --git a/app/features/send/cashu-send-swap-service.ts b/app/features/send/cashu-send-swap-service.ts
@@ -1,4 +1,9 @@
-import { MintOperationError, OutputData, type Proof } from '@cashu/cashu-ts';
+import {
+  MintOperationError,
+  OutputData,
+  type Proof,
+  type Token,
+} from '@cashu/cashu-ts';
 import type { CashuAccount } from '~/features/accounts/account';
 import {
   CashuErrorCodes,
@@ -8,9 +13,10 @@ import {
   getCashuUnit,
   isCashuError,
   sumProofs,
+  validateTokenSpendingConditions,
 } from '~/lib/cashu';
 import { createDeterministicP2PKData } from '~/lib/cashu/crypto';
-import type { SpendingConditionData } from '~/lib/cashu/types';
+import type { SpendingConditionData, UnlockingData } from '~/lib/cashu/types';
 import { Money } from '~/lib/money';
 import {
   type CashuTokenSwapService,
@@ -108,6 +114,7 @@ export class CashuSendSwapService {
     amount,
     senderPaysFee,
     spendingConditionData,
+    unlockingData,
   }: {
     /** The id of the user creating the swap */
     userId: string;
@@ -118,6 +125,7 @@ export class CashuSendSwapService {
     /** Whether the sender pays the fee for the swap by including the fee in the proofs to send */
     senderPaysFee: boolean;
     spendingConditionData?: SpendingConditionData;
+    unlockingData?: UnlockingData;
   }): Promise<CashuSendSwap> {
     if (account.currency !== amount.currency) {
       throw new Error(
@@ -204,6 +212,7 @@ export class CashuSendSwapService {
       keysetCounter: sendKeysetCounter,
       tokenHash,
       spendingConditionData,
+      unlockingData,
       outputAmounts: {
         send: amountsFromOutputData(sendOutputData),
         keep: amountsFromOutputData(keepOutputData),
@@ -300,15 +309,26 @@ export class CashuSendSwapService {
       throw new Error('Swap does not belong to account');
     }
 
+    const token: Token = {
+      mint: account.mintUrl,
+      proofs: swap.proofsToSend,
+      unit: getCashuProtocolUnit(swap.currency),
+    };
+
+    const unlockingData = swap.unlockingData ?? undefined;
+    if (unlockingData) {
+      const result = validateTokenSpendingConditions(token, unlockingData);
+      if (!result.success) {
+        throw new Error(result.error);
+      }
+    }
+
     return this.cashuTokenSwapService.create({
       account,
       userId: swap.userId,
-      token: {
-        mint: account.mintUrl,
-        proofs: swap.proofsToSend,
-        unit: getCashuProtocolUnit(swap.currency),
-      },
+      token,
       reversedTransactionId: swap.transactionId,
+      unlockingData,
     });
   }
 

diff --git a/app/features/send/cashu-send-swap.ts b/app/features/send/cashu-send-swap.ts
@@ -1,5 +1,5 @@
 import type { Proof } from '@cashu/cashu-ts';
-import type { SpendingConditionData } from '~/lib/cashu/types';
+import type { SpendingConditionData, UnlockingData } from '~/lib/cashu/types';
 import type { Currency, Money } from '~/lib/money';
 
 /**
@@ -68,6 +68,11 @@ export type CashuSendSwap = {
    * All the data required to encumber the proofs with the specified spending conditions.
    */
   spendingConditionData: SpendingConditionData | null;
+  /**
+   * All the data required to reclaim the proofs in the case that the user wants to reverse the swap.
+   * ie. refund keys
+   */
+  unlockingData: UnlockingData | null;
   /**
    * - DRAFT: The swap entity has been created, but there are no proofs to send yet. At this point,
    * we have only taken the inputProofs from the account

diff --git a/app/routes/_protected.demo.tsx b/app/routes/_protected.demo.tsx
@@ -273,6 +273,10 @@ function useDemoActions(
       amount: amountMoney,
       accountId: account.id,
       spendingConditionData,
+      unlockingData: {
+        kind: 'P2PK',
+        signingKeys: [state.privateKey],
+      },
     });
   };
 

diff --git a/supabase/database.types.ts b/supabase/database.types.ts
@@ -271,6 +271,7 @@ export type Database = {
           total_amount: number
           transaction_id: string
           unit: string
+          unlocking_data: string | null
           user_id: string
           version: number
         }
@@ -297,6 +298,7 @@ export type Database = {
           total_amount: number
           transaction_id: string
           unit: string
+          unlocking_data?: string | null
           user_id: string
           version?: number
         }
@@ -323,6 +325,7 @@ export type Database = {
           total_amount?: number
           transaction_id?: string
           unit?: string
+          unlocking_data?: string | null
           user_id?: string
           version?: number
         }
@@ -796,6 +799,7 @@ export type Database = {
           p_token_hash?: string
           p_total_amount: number
           p_unit: string
+          p_unlocking_data?: string
           p_updated_keyset_counter?: number
           p_user_id: string
         }
@@ -822,6 +826,7 @@ export type Database = {
           total_amount: number
           transaction_id: string
           unit: string
+          unlocking_data: string | null
           user_id: string
           version: number
         }