Defaults.Exposed › Methodology › v7 registry › Signature algorithm
Signature algorithm
Methodology v7 · canonical ID cert-signature-algorithm · TLS & Certificates · scored · census as of July 28, 2026
Uses a modern, unbroken signing algorithm (not legacy SHA-1).
Definition
| Canonical ID | cert-signature-algorithm |
|---|---|
| Category | TLS & Certificates |
| Grade impact | Scored — counts toward the grade |
| Pass | The certificate is signed with a modern algorithm (SHA-256 family or better). |
| Fail | The certificate is signed with a deprecated algorithm such as SHA-1 or MD5. |
| Example (passing) | Signature Algorithm: sha256WithRSAEncryption |
No-data rule: when this check couldn't be determined for a domain (timeout, SERVFAIL, redacted
source) it returns N/A and is excluded from that domain's scoring denominator — "couldn't determine"
is never counted as a failure. "Determined absent" is a real fail.
Prevalence across the census
The public census rollup does not publish a per-check figure for cert-signature-algorithm (as of July 28, 2026).
Whole-census aggregates live at /data; no number is shown here rather than an estimated one.
Census denominator: 275,666,275 graded domains. Aggregates only — never an individual domain's result.
Fix it
Plain-English impact, cost of ignoring it, and step-by-step remediation: defaults.exposed/en/fix/certificate
Cite this check
Defaults.Exposed, "Signature algorithm (cert-signature-algorithm)", Grading Methodology v7 (census as of July 28, 2026). https://defaults.exposed/methodology/v7/cert-signature-algorithm
Permalink: https://defaults.exposed/methodology/v7/cert-signature-algorithm ·
All 34 checks: v7 registry ·
Machine-readable: checks.json ·
Licence: open data