Japan digital public infrastructure APAC

Japan's Merged My Number App Makes National Digital ID the Default Login for Banks and Retailers

Digital Agency's August 25 app merger turns one government credential into the private sector's identity-check rail — with real fraud upside and a concentration risk to watch.

Japan's Identity Rail, By the Numbers People of Internet Research · Japan 81.2% Card penetration rate Share of Japan's population holdin… 19,056 Private-sector leak reports FY2024 data leak reports from priv… 2,052 My Number-linked leak incidents FY2024 incidents involving My Numb… 30+ hours Norway ID gateway outage Duration ID-porten and 4.5M+ users… peopleofinternet.com
Japan's Identity Rail, By the Numbers People of Internet Research · Japan 81.2% Card penetration rate 19,056 Private-sector leak reports 2,052 My Number-linked leak incidents 30+ hours Norway ID gateway outage peopleofinternet.com

Key Takeaways

One App, Two Worlds of Identity

On August 25, 2026, Japan's Digital Agency retired the split between Mynaportal — the app for filing government paperwork — and the standalone Digital Authentication App, folding both into a single "Myna App" (マイナアプリ). Existing Mynaportal users got the merge as a background update; anyone still on the old Digital Authentication App is now redirected into the unified app whenever they try to sign in or sign a document (Digital Agency, July 28, 2026).

The practical change is bigger than a UI cleanup. The same My Number Card credential — read via NFC into a smartphone and unlocked with a PIN or the phone's own biometric lock — now authenticates a citizen renewing a driver's license and a customer opening a brokerage account or completing an online retail purchase (ID Tech; News On Japan). Japan has offered this bridge into private-sector verification since 2016, when the Act on Public Personal Authentication was amended to let approved businesses tap the same certificate infrastructure — but it lived in a separate app most people never opened. Merging it into the portal citizens already use for tax filings and vaccination records is a deliberate default-adoption push, backed by a card base that had reached 81.2% of the population by the end of January 2026 (BCN+R).

The Case For It

The strongest argument for pushing everyone toward one chip-based, PIN-protected credential is that Japan's current private-sector identity-verification landscape is demonstrably leaky. The Personal Information Protection Commission's FY2024 annual report — covering the year to March 2025 — logged 19,056 data-leak reports from private businesses, a 57% jump and the highest since reporting began in 2017, plus 1,951 reports from public bodies, up 68%, mostly clerical errors like misdirected mail (PPC annual report). Of the 2,052 incidents specifically involving My Number data, 1,726 traced to a single vendor, MKSystem — a reminder that fragmenting identity verification across many private eKYC providers multiplies the number of places a leak can originate, not just the number of options consumers have. A single, cryptographically signed, tamper-resistant chip credential — verified in person at a municipal counter when the card is issued — is a plausible upgrade over the photo-ID-plus-selfie method that dominates online onboarding today and is comparatively easy to spoof with synthetic images. Consolidating two apps into one also removes a genuine UX failure: forcing citizens to discover, download, and configure a second app for private-sector use suppressed adoption of the more secure option in favor of whatever a bank's own scan-and-selfie flow offered.

The Risk Worth Naming

But collapsing public and private identity verification into one rail concentrates risk in ways a pro-innovation, security-conscious reader should not wave away. First, a competition concern: Japan hosts a real market of private eKYC vendors competing on onboarding speed, fraud-detection tooling, and price. As the Digital Agency's certificate service becomes the low-friction default embedded in an app most citizens already have, businesses have less reason to invest in differentiated verification products — narrowing a market to a single government-run utility is rarely how the best fraud-detection technology gets built. Second, a systemic-risk concern: previously, a Digital Authentication App outage or credential compromise was contained to whichever private services relied on it; a Mynaportal problem stayed within government services. One merged app means one outage or one compromised credential now touches both simultaneously — a single point of failure across two domains that used to fail independently. Norway offers a live illustration of what that looks like at scale: a DDoS attack that began August 24, 2026 against Digdir's IT partner Vivicta knocked out ID-porten, the login gateway behind more than 4.5 million Norwegians' access to banking, health records, and e-prescriptions, for over 30 hours — the third such incident since June (The Record). Japan is not Norway, and Myna App's local-device biometric lock adds a layer ID-porten's browser-based flow lacks — but the architectural lesson is the same: when one login gateway spans government and commerce, its downtime or breach radius grows with it.

The Proportionate Path

None of this argues against the merger — a harder-to-spoof, chip-based credential replacing selfie uploads is a genuine security upgrade, and giving citizens one app instead of two is basic product sense. But the Digital Agency should treat this as infrastructure that now carries systemic weight: publish uptime and incident-response commitments comparable to critical infrastructure, keep the underlying Digital Certificate Service API open so private eKYC vendors can build fraud-detection layers on top of the credential rather than being displaced by it, and resist any future move — mirroring the phase-out debate already underway around lower-security "photo ID plus selfie" onboarding methods under the Act on Prevention of Transfer of Criminal Proceeds — toward making the government credential the only legally acceptable path. A single strong option beats a single mandatory one.

Sources & Citations

  1. Digital Agency — Myna App launch notice
  2. Digital Agency — Digital Authentication App integration notice
  3. Personal Information Protection Commission — FY2024 annual report
  4. ID Tech — Japan merges identity portal and authentication apps
  5. News On Japan — My Number App launches with integrated ID verification
  6. The Record — Norway DDoS attack knocks public services offline
  7. BCN+R — My Number Card penetration rate