{
 "metric": "mx-tls-cert",
 "segment": "no-medium",
 "anchor": "company",
 "label": "Norway medium companies",
 "population": "Norway medium companies",
 "states": [
  "valid",
  "hostname_mismatch",
  "self_signed",
  "expired"
 ],
 "quiet_failure_states": [
  "self_signed",
  "expired"
 ],
 "measurement": "Complete STARTTLS, inspect the leaf certificate. Denominator: MXs offering STARTTLS.",
 "why_it_matters": "SMTP TLS is *opportunistic* (RFC 7435) — senders accept any certificate — so an invalid certificate still encrypts but authenticates nothing, leaving the connection open to interception. It only becomes a hard failure under DANE or MTA-STS `enforce`.",
 "limits": "Honesty demands the split. Because opportunistic TLS tolerates mismatches, only `self_signed` and `expired` are counted as the quiet failure; `hostname_mismatch` is reported but **not** counted.",
 "data_tier": "smtp",
 "population_predicate": "has_mx",
 "entity_type": "domain",
 "kind": "failure",
 "latest": {
  "day": "2026-08-14",
  "n": 218,
  "qf_pct": 0.46,
  "ci": [
   0.08,
   2.55
  ],
  "dist": {
   "valid": 97.71,
   "hostname_mismatch": 1.83,
   "self_signed": 0,
   "expired": 0.46
  },
  "snapshot": "brreg-norway-per600-seed20260730"
 },
 "series": [
  {
   "day": "2026-08-04",
   "n": 216,
   "qf_pct": 0.46,
   "ci": [
    0.08,
    2.58
   ],
   "dist": {
    "valid": 98.15,
    "hostname_mismatch": 1.39,
    "self_signed": 0,
    "expired": 0.46
   },
   "snapshot": "brreg-norway-per600-seed20260730"
  },
  {
   "day": "2026-08-05",
   "n": 216,
   "qf_pct": 0.46,
   "ci": [
    0.08,
    2.58
   ],
   "dist": {
    "valid": 97.69,
    "hostname_mismatch": 1.85,
    "self_signed": 0,
    "expired": 0.46
   },
   "snapshot": "brreg-norway-per600-seed20260730"
  },
  {
   "day": "2026-08-07",
   "n": 217,
   "qf_pct": 0.46,
   "ci": [
    0.08,
    2.56
   ],
   "dist": {
    "valid": 97.7,
    "hostname_mismatch": 1.84,
    "self_signed": 0,
    "expired": 0.46
   },
   "snapshot": "brreg-norway-per600-seed20260730"
  },
  {
   "day": "2026-08-14",
   "n": 218,
   "qf_pct": 0.46,
   "ci": [
    0.08,
    2.55
   ],
   "dist": {
    "valid": 97.71,
    "hostname_mismatch": 1.83,
    "self_signed": 0,
    "expired": 0.46
   },
   "snapshot": "brreg-norway-per600-seed20260730"
  }
 ],
 "license": "CC BY 4.0",
 "source": "https://quietfailures.com/datasets/mx-tls-cert/no-medium"
}