Certificate trust · Japan (domains)

What share of domains in Japan have a certificate that is self-signed or invalid for its hostname?

13.96%

13.96% of domains in Japan (95% CI 10.3–18.65%), measured across 265 domains on 2026-08-12.

ok: 86.04%hostname_mismatch: 11.32%self_signed: 2.64%
ok · 86.04%hostname_mismatch · 11.32%self_signed · 2.64%
Trend

Measured every Wednesday since 2026-08-01 — 5 observations to date. Last measured 2026-08-12.

How this is measured

Tier 2; compare issuer/subject and check the SAN list covers the host. Denominator: has_web.

Passive measurement: a single DNS lookup, TLS handshake, or homepage GET per domain. Aggregate-only; no individual company is named. 95% Wilson confidence intervals. Population: domains sampled from the Common Crawl web graph, filtered to those that do email. Parked domains excluded. Snapshot: common-crawl-domain-stratified-c400-g2500-seed20260729.

Licensed CC BY 4.0 — reuse with attribution to Quiet Failures. Download: JSON · CSV.

Why it matters

HTTPS is present, the port is open, TLS negotiates — and every visitor gets a browser warning, or would if they checked. Encryption without authentication.

The same check, other segments

Show the remaining 65 segments

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