---
id: "sctcrypto"
kind: "datatype"
status: "stable"
is_pii: false
categories: ["cryptography"]
langs: ["common"]
quality: 68
url: "http://registry.apicrafter.io/datatype/sctcrypto"
---

# Signed certificate timestamp (SCT) (`sctcrypto`)

Signed certificate timestamp (SCT) of Certificate Transparency (RFC 6962): a log's signed promise to add a certificate to its public Merkle tree within the maximum merge delay. SCTs are embedded in certificates, sent in a TLS extension or stapled to OCSP responses. In data an SCT is usually the Base64 encoding of its binary form. A version 1 SCT starts with a zero byte, so its Base64 starts with A; the regexp also requires the length of a 32-byte log ID, a timestamp and a signature.

- Personal data (PII): no
- Categories: Cryptographic identifiers (cryptography)
- Countries: global
- Languages: Common to most languages (common)
- Classification: identifier

## Detection

Regular expression (Python `re`):

```
^A[A-P][A-Za-z0-9+/]{140,}={0,2}$
```

## Examples

- `AETCvQzpFA5kpclKAZMKWqG7NZcOAO4RFoloKhxE17VmAAABoSW/+T4AAAQDAEYwRAIgTeyg6KAfX/46fQ8nvPsns52uWMnjMgcQ5c+pvT4tFBYCIBW4NkWlBKOjfM4SDzLUgf6mSlY1x1HmffO6b1VemlKD` — SCT embedded in the certificate of www.rfc-editor.org (October 2026)
- `SGVsbG8sIHdvcmxkIQ==` (invalid example) — Base64 of the text 'Hello, world!', not an SCT

## Sources

- doc: <https://www.rfc-editor.org/rfc/rfc6962#section-3.2>
- wikipedia: <https://en.wikipedia.org/wiki/Certificate_Transparency>

## Quality

Score 68/100. Missing: second example, mapping (Wikidata, Schema.org, ...), translation, detector coverage.

JSON: <http://registry.apicrafter.io/api/v1/datatypes/sctcrypto.json> · Edit: <https://github.com/apicrafter/metacrafter-registry/edit/main/data/datatypes/any/cryptography/sctcrypto.yaml>