# google/certificate-transparency-go

Auditing for TLS certificates (Go code)

Repository: https://github.com/google/certificate-transparency-go
Canonical: https://ross.abutalabs.com/products/certificate-transparency-go
Homepage: https://certificate.transparency.dev
Language: Go
License: Apache-2.0
License Family: permissive
Last push: 2026-09-02T15:31:42+00:00

## Health v2 (maintenance only)
Score: 82/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 48, longevity 100
- inputs: {"age_days": 3404, "days_push": 0, "days_rel": 188, "gap_med": 98.5, "n_releases_24m": 5}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1174, forks 320 (observed 2026-09-03T02:15:12.396686+00:00)

## What it is
Google's Go implementation of Certificate Transparency (RFC 6962), providing libraries for parsing and auditing TLS certificates, client libraries for querying CT logs, and a Trillian-backed CT log personality. It also ships CLI tools like ctclient and sctcheck for interacting with and verifying CT logs.

## Use cases
- audit TLS certificates for misissuance
- query a certificate transparency log
- verify signed certificate timestamps (SCTs)
- scan an entire CT log for certificates
- run a CT log server backed by Trillian
- parse malformed X.509 certificates in Go

## When to choose
- you need to interact with or audit Certificate Transparency logs in Go
- you want to operate a CT log with a Trillian backend
- you need to parse lenient/malformed X.509 certificates that strict libraries reject

## When to avoid
- you need general-purpose TLS termination or a web server
- you need CT support in a language other than Go
- you just need standard strict X.509 validation - use Go's crypto/x509

## Facets
- artifact type: library
- maturity: active
- function: security, cryptography, http-client, cli, parser
- domain: security, developer-tools, networking, apis
- platform: go, windows, cli
- tags: certificate-transparency, tls, x509, pki, merkle-tree, ct-log, trillian, linux, macos

## Member repositories
- google/certificate-transparency-go (main) score 82

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:12.396686+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:28:37.006493+00:00, confidence not recorded.
  - readme: https://github.com/google/certificate-transparency-go (fetched 2026-09-03T02:15:12.396686+00:00, sha c171d09fbed4)
  - homepage: https://certificate.transparency.dev (fetched 2026-08-29T12:34:15.048360+00:00, sha 6f868ac602bb)
- Data as of 2026-08-30T08:39:29.467469+00:00.