Validate Stellar DID/address format and remove hardcoded default recipient

src/components/modules/credential/hooks/use-credential-form.ts

@@ -5,6 +5,7 @@ import { useWalletContext } from '@/providers/wallet.provider';
 import { useDidContext } from '@/providers/did.provider';
 import { useCredential } from '@acta-team/credentials';
 import { toast } from 'sonner';
+import { isStellarTestnetDid } from '@/lib/validation';
 import type { CredentialFormState, VerifiableCredential } from '@/@types/credentials';
 
 export function useCredentialForm() {
@@ -13,7 +14,7 @@ export function useCredentialForm() {
   const { issue } = useCredential();
   const [state, setState] = useState<CredentialFormState>({
     issuerName: '',
-    subjectDid: 'did:pkh:stellar:testnet:GAGPI5M5M4CZHQPZSTXOWX4J6UQMUJWFKACPXDRQMZTK43GPOSPW6NVU',
+    subjectDid: '',
     degreeType: '',
     degreeName: '',
     validFrom: new Date().toISOString(),
@@ -46,6 +47,10 @@ export function useCredentialForm() {
       toast.error('Please fill all required fields');
       return;
     }
+    if (!isStellarTestnetDid(state.subjectDid)) {
+      toast.error('Invalid Subject DID format');
+      return;
+    }
     if (!signTransaction) {
       toast.error('Signer unavailable');
       return;

src/components/modules/credential/ui/CredentialForm.tsx

@@ -9,11 +9,14 @@ import {
   DialogDescription,
 } from '@/components/ui/dialog';
 import { useCredentialForm } from '../hooks/use-credential-form';
+import { isStellarTestnetDid } from '@/lib/validation';
 
 export function CredentialForm() {
   const { state, updateField, handleCreate, fillExample, walletAddress, ownerDid } =
     useCredentialForm();
 
+  const subjectDidInvalid = state.subjectDid.length > 0 && !isStellarTestnetDid(state.subjectDid);
+
   return !walletAddress ? (
     <div className="rounded border p-6 md:p-8 min-h-[20vh] flex flex-col items-center justify-center text-center">
       <p className="text-base">Connect your wallet to begin.</p>
@@ -102,7 +105,13 @@ export function CredentialForm() {
             value={state.subjectDid}
             onChange={(e) => updateField('subjectDid', e.target.value)}
             placeholder="did:pkh:stellar:testnet:GAGPI5M5M4CZHQPZSTXOWX4J6UQMUJWFKACPXDRQMZTK43GPOSPW6NVU"
+            aria-invalid={subjectDidInvalid}
           />
+          {subjectDidInvalid && (
+            <p className="text-xs text-red-500 mt-1">
+              Invalid Subject DID format. Expected did:pkh:stellar:testnet:&lt;Stellar address&gt;.
+            </p>
+          )}
           <Dialog
             open={state.openSubjectDidInfo}
             onOpenChange={(open) => updateField('openSubjectDidInfo', open)}

src/lib/validation.ts

@@ -0,0 +1,10 @@
+const STELLAR_ADDRESS_REGEX = /^G[A-Z2-7]{55}$/;
+const STELLAR_TESTNET_DID_REGEX = /^did:pkh:stellar:testnet:G[A-Z2-7]{55}$/;
+
+export function isStellarAddress(addr: string): boolean {
+  return STELLAR_ADDRESS_REGEX.test(addr);
+}
+
+export function isStellarTestnetDid(did: string): boolean {
+  return STELLAR_TESTNET_DID_REGEX.test(did);
+}

src/providers/did.provider.tsx

@@ -2,6 +2,7 @@
 
 import React, { createContext, useContext, useEffect, useMemo, useState } from 'react';
 import { useWalletContext } from '@/providers/wallet.provider';
+import { isStellarAddress } from '@/lib/validation';
 
 type DidContextValue = {
   ownerDid: string | null;
@@ -10,7 +11,8 @@ type DidContextValue = {
 
 const DidContext = createContext<DidContextValue | undefined>(undefined);
 
-export function makeDidForAddress(address: string): string {
+export function makeDidForAddress(address: string): string | null {
+  if (!isStellarAddress(address)) return null;
   // Always use testnet for this demo
   return `did:pkh:stellar:testnet:${address}`;
 }