chore: use io-ts to parse vault keycard box + update keycard formatting and QR headers

modules/key-card/package.json

@@ -36,6 +36,9 @@
     "@bitgo/sdk-api": "^2.0.0",
     "@bitgo/sdk-core": "^38.0.0",
     "@bitgo/statics": "^58.54.0",
+    "fp-ts": "^2.16.2",
+    "io-ts": "npm:@bitgo-forks/io-ts@2.1.4",
+    "io-ts-types": "^0.5.19",
     "jspdf": ">=4.2.0",
     "pdfjs-dist": "^4.0.0",
     "qrcode": "^1.5.1"

modules/key-card/src/drawKeycard.ts

@@ -56,34 +56,67 @@ function moveDown(y: number, ydelta: number): number {
   return y + ydelta;
 }
 
+/**
+ * Prefixes one fragment of a split key with a part header so a QR scanner can reassemble the
+ * fragments without relying on scan order.
+ *
+ * When a key box's payload exceeds {@link QRBinaryMaxLength}, {@link splitKeys} divides it into
+ * multiple QR codes. Each fragment's QR payload is encoded as a 1-based part header followed by
+ * the fragment:
+ *
+ *     "<index>/<total>|<fragment>"      e.g.  "1/3|<chunk>", "2/3|<chunk>", "3/3|<chunk>"
+ *
+ * A single-fragment payload is returned unchanged (no header).
+ *
+ * Reassembly contract for a consumer (e.g. a future recovery/scan tool):
+ *   1. Scan every QR code for a box.
+ *   2. Split each payload on the FIRST "|": the left side is "<index>/<total>", the right side
+ *      is the fragment.
+ *   3. Verify parts 1..total are all present (total is identical in every header).
+ *   4. Concatenate the fragments in ascending index order to recover the full box payload.
+ *   5. Parse/decrypt as usual (for a vault box: JSON.parse, then decrypt each root value).
+ *
+ * Notes:
+ *   - The "|" delimiter is safe: base64 ciphertext, JSON, and base58 xpubs never contain it.
+ *   - This header exists ONLY inside the QR image. The human-readable "Data:" text printed on
+ *     the card is the full, unheadered payload; the PDF-text parser reads that, so this header
+ *     does not affect PDF-based recovery.
+ */
+function encodeQrCodePart(fragment: string, index: number, total: number): string {
+  return total > 1 ? `${index + 1}/${total}|${fragment}` : fragment;
+}
+
+// Draws QR codes down the left column, returning the index of the next QR still to draw
+// (for continuation on a later page) and the y-offset just below the drawn QR column (so
+// callers can place content, e.g. a note, under the QR codes).
 function drawOnePageOfQrCodes(
   qrImages: HTMLCanvasElement[],
   doc: jsPDF,
   y: number,
   qrSize: number,
-  startIndex
-): number {
+  startIndex: number
+): { nextIndex: number; endY: number } {
   doc.setFont('helvetica');
   let qrIndex: number = startIndex;
   for (; qrIndex < qrImages.length; qrIndex++) {
     const image = qrImages[qrIndex];
     const textBuffer = 15;
     if (y + qrSize + textBuffer >= doc.internal.pageSize.getHeight()) {
-      return qrIndex;
+      return { nextIndex: qrIndex, endY: y };
     }
 
     doc.addImage(image, left(0), y, qrSize, qrSize);
 
     if (qrImages.length === 1) {
-      return qrIndex + 1;
+      return { nextIndex: qrIndex + 1, endY: y + qrSize };
     }
 
     y = moveDown(y, qrSize + textBuffer);
     doc.setFontSize(font.body).setTextColor(color.black);
     doc.text('Part ' + (qrIndex + 1).toString(), left(0), y);
     y = moveDown(y, 20);
   }
-  return qrIndex + 1;
+  return { nextIndex: qrIndex, endY: y };
 }
 
 function computeKeyCardImageDimensions(keyCardImage: HTMLImageElement) {
@@ -115,6 +148,7 @@ export async function drawKeycard({
   walletLabel,
   curve,
   pageBreakBeforeIndices = DEFAULT_PAGE_BREAK_INDICES,
+  useQrPartHeaders = false,
 }: IDrawKeyCard): Promise<jsPDF> {
   const jsPDFModule = await loadJSPDF();
 
@@ -203,11 +237,26 @@ export async function drawKeycard({
 
     const qrImages: HTMLCanvasElement[] = [];
     const keys = splitKeys(qr.data, QRBinaryMaxLength);
-    for (const key of keys) {
-      qrImages.push(await QRCode.toCanvas(key, { errorCorrectionLevel: 'L' }));
+    for (let i = 0; i < keys.length; i++) {
+      const payload = useQrPartHeaders ? encodeQrCodePart(keys[i], i, keys.length) : keys[i];
+      qrImages.push(await QRCode.toCanvas(payload, { errorCorrectionLevel: 'L' }));
     }
 
-    let nextQrIndex = drawOnePageOfQrCodes(qrImages, doc, y, qrSize, 0);
+    const isMultiPart = qr?.data?.length > QRBinaryMaxLength;
+    const { nextIndex, endY: qrColumnEndY } = drawOnePageOfQrCodes(qrImages, doc, y, qrSize, 0);
+    let nextQrIndex = nextIndex;
+
+    // For a split key, place the "put all Parts together" note directly under the QR codes.
+    // Wrap it to the QR column width so it stays in the left column and never overlaps the
+    // Data payload rendered on the right.
+    let qrColumnBottom = qrColumnEndY;
+    if (isMultiPart) {
+      doc.setFontSize(font.body - 2).setTextColor(color.darkgray);
+      const noteLines = doc.splitTextToSize('Note: you will need to put all Parts together for the full key', qrSize);
+      const noteY = moveDown(qrColumnEndY, 15);
+      doc.text(noteLines, left(0), noteY);
+      qrColumnBottom = noteY + noteLines.length * doc.getLineHeight();
+    }
 
     doc.setFontSize(font.subheader).setTextColor(color.black);
     y = moveDown(y, 10);
@@ -220,11 +269,6 @@ export async function drawKeycard({
     doc.text(qr.description, textLeft, y);
     textHeight += doc.getLineHeight();
     doc.setFontSize(font.body - 2);
-    if (qr?.data?.length > QRBinaryMaxLength) {
-      y = moveDown(y, 30);
-      textHeight += 30;
-      doc.text('Note: you will need to put all Parts together for the full key', textLeft, y);
-    }
     y = moveDown(y, 30);
     textHeight += 30;
     doc.text('Data:', textLeft, y);
@@ -242,7 +286,11 @@ export async function drawKeycard({
         textHeight = 0;
         y = 30;
         topY = y;
-        nextQrIndex = drawOnePageOfQrCodes(qrImages, doc, y, qrSize, nextQrIndex);
+        // Redraw remaining QRs on the new page and update the column bottom to THIS page, so
+        // the rowHeight math below stays same-page (avoids a stale page-1 coordinate).
+        const continued = drawOnePageOfQrCodes(qrImages, doc, y, qrSize, nextQrIndex);
+        nextQrIndex = continued.nextIndex;
+        qrColumnBottom = continued.endY;
         doc.setFont('courier').setFontSize(9).setTextColor(color.black);
       }
       doc.text(lines[line], textLeft, y);
@@ -273,9 +321,10 @@ export async function drawKeycard({
     }
 
     doc.setFont('helvetica');
-    // Move down the size of the QR code minus accumulated height on the right side, plus margin
-    // if we have a key that spans multiple pages, then exclude QR code size
-    const rowHeight = Math.max(qr.data.length > QRBinaryMaxLength ? qrSize + 20 : qrSize, textHeight);
+    // Move down past the taller of the two columns: the right-side text (textHeight) or the
+    // left-side QR column (plus the note printed under it for split keys), then add a margin.
+    const qrColumnHeight = isMultiPart ? qrColumnBottom - topY : qrSize;
+    const rowHeight = Math.max(qrColumnHeight, textHeight);
     const marginBottom = 15;
     y = moveDown(y, rowHeight - (y - topY) + marginBottom);
   }

modules/key-card/src/generateQrData.ts

@@ -6,6 +6,7 @@ import {
   GenerateLightningQrDataParams,
   GenerateQrDataParams,
   GenerateVaultQrDataParams,
+  KeycardEntity,
   MasterPublicKeyQrDataEntry,
   QrData,
   QrDataEntry,
@@ -135,13 +136,15 @@ function generateUserMasterPublicKeyQRData(publicKey: string): MasterPublicKeyQr
 async function generatePasscodeQrData(
   passphrase: string,
   passcodeEncryptionCode: string,
-  encryptionVersion?: 1 | 2
+  encryptionVersion?: 1 | 2,
+  entityNoun: KeycardEntity = 'wallet'
 ): Promise<QrDataEntry> {
-  const encryptedWalletPasscode = await encrypt(passcodeEncryptionCode, passphrase, { encryptionVersion });
+  const encryptedPasscode = await encrypt(passcodeEncryptionCode, passphrase, { encryptionVersion });
+  const titleNoun = entityNoun === 'vault' ? 'Vault' : 'Wallet';
   return {
-    title: 'D: Encrypted Wallet Password',
-    description: 'This is the wallet password, encrypted client-side with a key held by BitGo.',
-    data: encryptedWalletPasscode,
+    title: `D: Encrypted ${titleNoun} Password`,
+    description: `This is the ${entityNoun} password, encrypted client-side with a key held by BitGo.`,
+    data: encryptedPasscode,
   };
 }
 
@@ -263,12 +266,12 @@ export async function generateVaultQrData(params: GenerateVaultQrDataParams): Pr
   const qrData: QrData = {
     user: {
       title: 'A: User Key',
-      description: 'Your 4 root private keys, encrypted with your wallet password.',
+      description: 'Your 4 root private keys, encrypted with your vault password.',
       data: buildVaultBoxData(roots, (root, slot) => selectRootPrivateKey(root.userKeychain, slot, 'user')),
     },
     backup: {
       title: 'B: Backup Key',
-      description: 'Your 4 root backup keys, encrypted with your wallet password.',
+      description: 'Your 4 root backup keys, encrypted with your vault password.',
       data: buildVaultBoxData(roots, (root, slot) => selectRootPrivateKey(root.backupKeychain, slot, 'backup')),
     },
     bitgo: {
@@ -282,7 +285,8 @@ export async function generateVaultQrData(params: GenerateVaultQrDataParams): Pr
     qrData.passcode = await generatePasscodeQrData(
       params.passphrase,
       params.passcodeEncryptionCode,
-      params.encryptionVersion
+      params.encryptionVersion,
+      'vault'
     );
   }
 

modules/key-card/src/index.ts

@@ -61,7 +61,13 @@ export async function generateVaultKeycard(
 ): Promise<void> {
   const questions = generateFaq(params.coin.fullName);
   const qrData = await generateVaultQrData(params);
-  const keycard = await drawKeycard({ ...params, questions, qrData, pageBreakBeforeIndices: [1, 2] });
+  const keycard = await drawKeycard({
+    ...params,
+    questions,
+    qrData,
+    pageBreakBeforeIndices: [1, 2],
+    useQrPartHeaders: true,
+  });
   const label = params.walletLabel || params.coin.fullName;
   keycard.save(`BitGo Keycard for ${label}.pdf`);
 }

modules/key-card/src/parseKeycard.ts

@@ -1,4 +1,8 @@
-import { VaultKeycardRoots, VAULT_ROOT_ORDER } from './types';
+import * as t from 'io-ts';
+import { isLeft } from 'fp-ts/Either';
+import { PathReporter } from 'io-ts/lib/PathReporter';
+import { JsonFromString } from 'io-ts-types';
+import { VaultKeycardRoots } from './types';
 
 export type PDFTextNode = {
   text: string;
@@ -13,29 +17,31 @@ export type KeycardEntry = {
   value: string;
 };
 
+// A vault keycard box is a JSON object mapping each rootKeyType to a string (per-root
+// ciphertext for A/B, public key for C).
+const VaultKeycardRootsCodec: t.Type<VaultKeycardRoots> = t.type({
+  secp256k1Multisig: t.string,
+  ecdsaMpc: t.string,
+  eddsaMpc: t.string,
+  ed25519Multisig: t.string,
+});
+
+// Decodes a box's JSON string straight into the validated roots record.
+const VaultKeycardBoxFromString = JsonFromString.pipe(VaultKeycardRootsCodec);
+
 /**
  * Parses a vault keycard box value — the JSON packed by `generateVaultQrData`, e.g.
- * `{"secp256k1Multisig":"…","ecdsaMpc":"…",…}` — into its four roots. Validates that all four
- * roots are present. Recovery tooling calls this on the A/B/C box value returned by
- * {@link parseKeycardFromLines}, then decrypts each root value with the wallet password.
+ * `{"secp256k1Multisig":"…","ecdsaMpc":"…",…}` — into its four roots. Throws if the value is
+ * not valid JSON or any root is missing/non-string. Recovery tooling calls this on the A/B/C
+ * box value returned by {@link parseKeycardFromLines}, then decrypts each root value with the
+ * vault password.
  */
 export function parseVaultKeycardBox(data: string): VaultKeycardRoots {
-  let parsed: unknown;
-  try {
-    parsed = JSON.parse(data);
-  } catch {
-    throw new Error('parseVaultKeycardBox: value is not valid JSON');
-  }
-  if (typeof parsed !== 'object' || parsed === null) {
-    throw new Error('parseVaultKeycardBox: value is not an object');
-  }
-  const roots = parsed as Record<string, unknown>;
-  for (const slot of VAULT_ROOT_ORDER) {
-    if (typeof roots[slot] !== 'string') {
-      throw new Error(`parseVaultKeycardBox: missing or invalid root ${slot}`);
-    }
+  const decoded = VaultKeycardBoxFromString.decode(data);
+  if (isLeft(decoded)) {
+    throw new Error(`parseVaultKeycardBox: ${PathReporter.report(decoded).join('; ')}`);
   }
-  return parsed as VaultKeycardRoots;
+  return decoded.right;
 }
 
 const sectionHeaderRegex = /^([A-D])\s*[:.)-]\s*(.+?)\s*$/i;
@@ -73,7 +79,9 @@ function countChar(input: string, char: string): number {
 }
 
 function isEncryptedWalletPasswordSectionTitle(title: string): boolean {
-  return title.toLowerCase().includes('encrypted wallet password');
+  const normalized = title.toLowerCase();
+  // Box D is titled "Encrypted Wallet Password" (wallet) or "Encrypted Vault Password" (vault).
+  return normalized.includes('encrypted wallet password') || normalized.includes('encrypted vault password');
 }
 
 /**

modules/key-card/src/types.ts

@@ -76,6 +76,9 @@ export const VAULT_ROOT_ORDER: VaultRootKeyType[] = ['secp256k1Multisig', 'ecdsa
  */
 export type VaultKeycardRoots = Record<VaultRootKeyType, string>;
 
+/** The product a keycard belongs to, used for user-facing wording (e.g. Box D copy). */
+export type KeycardEntity = 'wallet' | 'vault';
+
 export interface GenerateVaultQrDataParams extends GenerateQrDataCoinParams {
   // The four root triplets (user/backup/bitgo keychains), keyed by rootKeyType.
   roots: Record<VaultRootKeyType, KeychainsTriplet>;
@@ -91,8 +94,12 @@ export interface IDrawKeyCard {
   questions: FAQ[];
   walletLabel?: string;
   curve?: KeyCurve;
-  // Box indices to start a new page before. Omit for the default wallet layout.
+  // Insert page breaks at the given box indices. If not provided, defaults to single break before the 3rd box (default layout).
   pageBreakBeforeIndices?: number[];
+  // When true, a split key's QR fragments are prefixed with a "<index>/<total>|" part header
+  // so a scanner can reassemble them. Opt-in (used by the vault keycard); omit to leave QR
+  // payloads as raw fragments, keeping the wallet keycard output unchanged.
+  useQrPartHeaders?: boolean;
 }
 
 export interface FAQ {

modules/key-card/test/unit/vaultQrData.ts

@@ -131,17 +131,20 @@ describe('generateVaultQrData', function () {
     userBox['ed25519Multisig'].should.equal(roots.ed25519Multisig.userKeychain.encryptedPrv);
   });
 
-  it('includes box D when passphrase + passcodeEncryptionCode are provided', async function () {
+  it('includes box D with vault wording when passphrase + passcodeEncryptionCode are provided', async function () {
     const { roots } = await buildRoots();
     const qrData = await generateVaultQrData({
       coin: coins.get('btc'),
       roots,
-      passphrase: 'wallet-pw',
+      passphrase: 'vault-pw',
       passcodeEncryptionCode: '123456',
     });
     assert.ok(qrData.passcode);
-    qrData.passcode.title.should.equal('D: Encrypted Wallet Password');
-    (await decrypt('123456', qrData.passcode.data)).should.equal('wallet-pw');
+    qrData.passcode.title.should.equal('D: Encrypted Vault Password');
+    qrData.passcode.description.should.equal(
+      'This is the vault password, encrypted client-side with a key held by BitGo.'
+    );
+    (await decrypt('123456', qrData.passcode.data)).should.equal('vault-pw');
   });
 
   it('throws when a user root is missing private key material', async function () {
@@ -187,8 +190,11 @@ describe('generateVaultQrData', function () {
   });
 
   it('parseVaultKeycardBox rejects malformed / incomplete box data', function () {
-    assert.throws(() => parseVaultKeycardBox('not json'), /not valid JSON/);
-    assert.throws(() => parseVaultKeycardBox('"a string"'), /not an object/);
-    assert.throws(() => parseVaultKeycardBox('{"secp256k1Multisig":"x"}'), /missing or invalid root/);
+    assert.throws(() => parseVaultKeycardBox('not json'), /parseVaultKeycardBox/); // invalid JSON
+    assert.throws(() => parseVaultKeycardBox('"a string"'), /parseVaultKeycardBox/); // not an object
+    assert.throws(() => parseVaultKeycardBox('{"secp256k1Multisig":"x"}'), /parseVaultKeycardBox/); // missing roots
+    // A well-formed box with all four roots decodes successfully.
+    const ok = parseVaultKeycardBox('{"secp256k1Multisig":"a","ecdsaMpc":"b","eddsaMpc":"c","ed25519Multisig":"d"}');
+    ok.ecdsaMpc.should.equal('b');
   });
 });