fix: trim template in signature payload to prevent whitespace mismatch

Author: Corey B

examples/bank_statement_v2.fdd

@@ -9,7 +9,7 @@
         "VerifiableCredential"
       ],
       "issuer": "did:web:spuds0588.github.io:open-fdd",
-      "issuanceDate": "2026-04-12T04:28:27.881Z",
+      "issuanceDate": "2026-04-12T04:48:42.859Z",
       "credentialSubject": {
         "bankName": "First National Bank",
         "accountHolder": "Jordan M. Castillo",
@@ -123,10 +123,10 @@
       },
       "proof": {
         "type": "Ed25519Signature2020",
-        "created": "2026-04-12T04:28:27.883Z",
+        "created": "2026-04-12T04:48:42.861Z",
         "proofPurpose": "assertionMethod",
         "verificationMethod": "did:web:spuds0588.github.io:open-fdd#key-1",
-        "signatureValue": "HD4kZWfbRiXWmG94FaI1WyKPjJLah9Ebtb+kYrU7GXVlsOb3z8Lxq9U0o4fuozvhwfaGuwjkvBHl/BhCLQ38DA=="
+        "signatureValue": "lYrOkcUX+t0CfThS2M+wE38Fkpd/Frn5gdl1jBQsn/J5PYNLWP6IgxpgRhFSemrw2Y7dvtLNOXlGPxHiqIWLBg=="
       }
     }
   </script>
@@ -138,8 +138,7 @@
   </script>
 
   <template shadowrootmode="open" bind="#fdd-data, #user-notes">
-
-    <style>
+<style>
       * { box-sizing: border-box; margin: 0; padding: 0; }
       .stmt { max-width: 820px; margin: 2rem auto; font-family: 'Segoe UI', system-ui, sans-serif; color: #1e293b; }
       .header { background: linear-gradient(135deg, #1e3a5f, #0ea5e9); color: white; padding: 2rem; border-radius: 8px 8px 0 0; display: flex; justify-content: space-between; align-items: flex-end; }
@@ -216,6 +215,5 @@
         <span>This statement is a Formatted Data Document (.fdd) — tamper-evident and machine-readable.</span>
       </div>
     </div>
-  
   </template>
 </fdd-container>

examples/legal_contract.fdd

@@ -9,7 +9,7 @@
         "VerifiableCredential"
       ],
       "issuer": "did:web:spuds0588.github.io:open-fdd",
-      "issuanceDate": "2026-04-12T04:28:27.888Z",
+      "issuanceDate": "2026-04-12T04:48:42.866Z",
       "credentialSubject": {
         "documentTitle": "Consulting Services Agreement",
         "documentId": "HSL-2026-0041",
@@ -55,10 +55,10 @@
       },
       "proof": {
         "type": "Ed25519Signature2020",
-        "created": "2026-04-12T04:28:27.888Z",
+        "created": "2026-04-12T04:48:42.866Z",
         "proofPurpose": "assertionMethod",
         "verificationMethod": "did:web:spuds0588.github.io:open-fdd#key-1",
-        "signatureValue": "HuZG30SseNW9Cf3c+j4BoIq6/70XRTJplYb2jpe5Gsn1XrKDFmVsVN/SLOvZt+753OxnRh8y1/b8Byxmzam9AA=="
+        "signatureValue": "L6pVN8/fjzlL3wCxeHrcHbiMKzn2FpwwQXa+08dBR//m3TKRKtACFke6wtDhyPfChXkopX9u29CZtUVYG2QeAw=="
       }
     }
   </script>
@@ -72,8 +72,7 @@
   </script>
 
   <template shadowrootmode="open" bind="#fdd-data, #user-notes">
-
-    <style>
+<style>
       * { box-sizing: border-box; margin: 0; padding: 0; }
       .doc { max-width: 760px; margin: 2rem auto; padding: 2.5rem; background: #fff; border: 1px solid #d1d5db; font-family: 'Times New Roman', Georgia, serif; color: #1a1a1a; }
       .doc-title { text-align: center; font-size: 1.5rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 0.25rem; }
@@ -156,6 +155,5 @@
         Governing Law: {{governingLaw}} · This document is cryptographically signed. Issuer: did:web:hartwell-law.example
       </div>
     </div>
-  
   </template>
 </fdd-container>

examples/medical_lab_result.fdd

@@ -9,7 +9,7 @@
         "VerifiableCredential"
       ],
       "issuer": "did:web:spuds0588.github.io:open-fdd",
-      "issuanceDate": "2026-04-12T04:28:27.886Z",
+      "issuanceDate": "2026-04-12T04:48:42.864Z",
       "credentialSubject": {
         "patientName": "Alexandra Rivera",
         "dateOfBirth": "1987-03-22",
@@ -65,10 +65,10 @@
       },
       "proof": {
         "type": "Ed25519Signature2020",
-        "created": "2026-04-12T04:28:27.886Z",
+        "created": "2026-04-12T04:48:42.864Z",
         "proofPurpose": "assertionMethod",
         "verificationMethod": "did:web:spuds0588.github.io:open-fdd#key-1",
-        "signatureValue": "hrFWVQ03c9lflDzjzxdr1rRb43R2+H+rgK8LlcbE/YbZ1ZetACkfOR/g+nCw1J1er7o1oz935mcQv1WKy0VSCQ=="
+        "signatureValue": "zYsuQ+vfunqtiv+WSIHCNS0hwj1TTYV9vDpYfS/+fdh2zpHPkTXdfGa63XNOVtzdV/rgjmEzo6Nc+1sKlF65CQ=="
       }
     }
   </script>
@@ -80,8 +80,7 @@
   </script>
 
   <template shadowrootmode="open" bind="#fdd-data, #user-notes">
-
-    <style>
+<style>
       * { box-sizing: border-box; margin: 0; padding: 0; }
       body { font-family: 'Segoe UI', system-ui, sans-serif; }
       .report { max-width: 800px; margin: 2rem auto; padding: 2rem; background: #fff; border: 1px solid #e2e8f0; border-radius: 8px; }
@@ -151,6 +150,5 @@
         Issuer: did:web:valleymedical.example
       </div>
     </div>
-  
   </template>
 </fdd-container>

lib/node-fdd/src/sign.js

@@ -29,6 +29,7 @@ import path from 'path';
  * @returns {string} - Complete .fdd file content
  */
 export function signFdd(data, template, privateKeyPem, issuerUri, mutableData = {}) {
+  template = template.trim();
   const privateKey = crypto.createPrivateKey(privateKeyPem);
 
   // Build the Verifiable Credential wrapper (without proof first)
@@ -132,7 +133,7 @@ export async function verify(fddString) {
   delete vcWithoutProof.proof;
 
   const templateMatch = fddString.match(/<template[^>]*>([\s\S]*?)<\/template>/i);
-  const template = templateMatch ? templateMatch[1] : '';
+  const template = templateMatch ? templateMatch[1].trim() : '';
   const payload = Buffer.from(JSON.stringify(vcWithoutProof) + '\n---template---\n' + template, 'utf8');
 
   try {

site/sandbox.html

@@ -464,7 +464,7 @@ <h1>Statement for {{accountHolder}}</h1>
   // step 6
   set('payload','run', N('Reconstructing the exact byte sequence that was signed…'));
   const tmplMatch = source.match(/<template[^>]*>([\s\S]*?)<\/template>/i);
-  const tmpl = tmplMatch ? tmplMatch[1] : '';
+  const tmpl = tmplMatch ? tmplMatch[1].trim() : '';
   const vcNP = JSON.parse(JSON.stringify(vc)); delete vcNP.proof;
   const payloadStr = JSON.stringify(vcNP) + '\n---template---\n' + tmpl;
   const payloadBytes = new TextEncoder().encode(payloadStr);