Product Specification v0.1
Internal Working Document
April 2026
Product Concept — LOCKD Vault

Your most important
documents. Unbreakable.

A zero-knowledge encrypted vault for critical personal documents — passports, birth certificates, driving licences — with biometric access, smart formatting, and emergency sharing built in.

01 — Overview

The Problem

People store their most sensitive documents in the worst possible places — email threads, WhatsApp, unencrypted cloud folders. When they need them urgently (visa application, rental, job offer), they either can't find them or have to send them over insecure channels.

There's no dedicated, secure, intelligent home for critical personal documents.

The Opportunity

LOCKD already owns the trust layer for file transfer. The Vault extends that brand promise into personal document management — a natural product adjacency that deepens user retention and creates a recurring revenue stream independent of file-send volume.

The vault becomes the reason people open LOCKD every month, not just when they have something to send.

02 — Core Features

What the Vault does

F-01

Biometric Entry

Face ID / Touch ID / Passkey access. Biometric unlocks the device Secure Enclave which releases the decryption key. No password, no PIN — nothing to phish.

MVPiOSAndroid
F-02

Zero-Knowledge Encryption

Files encrypted client-side before upload. LOCKD servers hold only ciphertext — even a breach exposes nothing readable. Full AES-256 + key derivation.

MVPSecurity
F-03

Smart Document Types

Vault understands document categories — passport, driving licence, birth cert, marriage cert, visa, insurance. Extracts key fields (expiry date, number) automatically.

MVPOCR
F-04

Expiry Alerts

Tracks expiry dates and sends smart reminders at 6 months, 3 months, 1 month. Passports, visas, driving licences — never get caught out at an airport again.

MVPPush Notifications
F-05

Photo Formatting Engine

Upload a selfie, get back a correctly-spec'd photo for UK passport, US visa, ESTA, driving licence renewal, or any supported application type. Auto-cropped, correct background, correct dimensions.

MVPAIHigh Value
F-06

Secure Share Links

Generate a time-limited, view-only link to share a document with a landlord, employer, or solicitor. Link expires after 24hrs (or custom duration). No download, no forwarding. Recipient sees, not owns.

MVPCore LOCKD DNA
F-07

Emergency Access

Nominate a trusted contact. If they request emergency access and you don't deny it within 48hrs, they get in. Designed for when you're incapacitated or abroad without your phone.

V2Trust & Safety
F-08

Auto-fill Profile

Store NI number, passport number, date of birth, address history. Auto-populate government forms, visa applications, job application portals. One vault, endless form-filling use.

V2Productivity
F-09

Family Vault

Extend vault to cover your household — partner, kids, elderly parents. Manage multiple people's documents from one authenticated account. Separate permissions per person.

V3Growth
03 — Feature Focus: Photo Formatting

The passport photo opportunity

This is a genuine standalone value proposition. People pay £10–15 at a pharmacy for a photo that meets passport specs. LOCKD Vault could do it from your camera roll instantly — and it would be used repeatedly across different application types.

Supported Formats (MVP)

  • → UK Passport (35×45mm, neutral background)
  • → US Visa / ESTA (2×2 inch, white background)
  • → Irish Passport
  • → EU Biometric Residence Permit
  • → UK Driving Licence Renewal

How it works

User takes or uploads a photo → AI detects face, checks expression and eye position → crops to correct dimensions → replaces background to spec → outputs print-ready file and digital version. All processed on-device or via secure API — image never stored post-processing.

Face detection Background removal Compliance check Export to PDF
04 — Security Architecture

How the encryption works

Entry Layer
Biometric → Secure Enclave — Face ID / Touch ID authenticates to device hardware. Enclave releases symmetric key. No biometric data ever leaves the device or touches LOCKD servers.
Key Layer
Client-side key derivation — A unique vault key is generated per user using PBKDF2 or Argon2. This key encrypts all documents before upload. LOCKD never sees it. Backed up to device Keychain (iOS) or Keystore (Android) only.
Storage Layer
AES-256-GCM encryption at rest — Uploaded blobs are ciphertext. Our servers are a dumb encrypted blob store. A breach of our infrastructure yields nothing useful to an attacker.
Transit Layer
TLS 1.3 in transit — Standard transport encryption. Since files are already encrypted before upload, this is a second layer, not the primary security mechanism.
Share Layer
Time-limited signed URLs — Secure share links are cryptographically signed, expire on schedule, and generate audit logs. Recipient access is view-only via a sandboxed viewer — no raw file download.
05 — Prioritised Roadmap

What to build and when

Feature Phase Rationale Complexity
Biometric entry + encryption MVP Non-negotiable foundation. No vault without this. Medium
Document storage + smart types MVP Core utility. Must support at least 8 doc types on launch. Low
Expiry alerts MVP Immediate tangible value. Drives daily open habit. Low
Secure share links MVP Core LOCKD DNA. Differentiates from simple cloud storage. Low–Medium
Photo formatting engine MVP Unique, high-value, drives word-of-mouth. Strong upsell. Medium
Emergency access V2 Trust-building feature. Important for long-term retention. Medium
Auto-fill profile V2 Productivity layer. High stickiness once set up. Medium–High
Family vault V3 Growth multiplier. One converted user becomes 2–4 accounts. High
06 — Monetisation

Revenue model

Free
£0
  • Up to 5 documents
  • Biometric access
  • Expiry reminders
  • 1 secure share link/month
  • 1 photo format/month
Vault Pro
£3.99/mo
  • Unlimited documents
  • Unlimited share links
  • Unlimited photo formatting
  • All format types (10+)
  • Emergency access
  • Auto-fill profile
Family
£7.99/mo
  • Everything in Pro
  • Up to 5 family members
  • Separate permissions
  • Shared emergency access
  • Family expiry dashboard

Note: Photo formatting could also be offered as a one-time credit purchase (e.g. £0.99 per additional format) to capture non-subscribers. High perceived value relative to cost.

07 — Open Questions

Decisions to make

Q1
Standalone app or feature within LOCKD?

Does LOCKD Vault live as a tab/feature inside the main app, or does it deserve its own app with its own brand? Separate app = cleaner security story + own subscription. Integrated = easier cross-sell, shared auth.

Q2
What happens if the user loses their phone?

Zero-knowledge encryption is great until the device is gone. Need a clear recovery story — seed phrase? Recovery contact? iCloud Keychain backup? This needs to be resolved before MVP. Users storing birth certs here will ask.

Q3
Photo formatting — on-device or API?

On-device (Core ML / ML Kit) is better for privacy and speed but harder to build. API-based (remove.bg + custom crop logic) is faster to ship but adds a network hop with sensitive images. For MVP, API may be acceptable with a clear data deletion policy.

Q4
Compliance and regulated document storage?

Are there any obligations once LOCKD is known to store passport scans and identity documents? Worth a brief legal review — particularly around GDPR, data minimisation, and what happens on account deletion.

Q5
Positioning — vault as security play or convenience play?

"Never lose your passport again" is a consumer message. "Zero-knowledge encrypted document vault" is a security message. These attract different users. The photo formatting angle bridges both — practical utility with a trusted security wrapper.