---
id: "ssh_key_fingerprint"
kind: "datatype"
status: "draft"
is_pii: false
categories: ["cryptography"]
langs: ["common"]
quality: 75
url: "http://registry.apicrafter.io/datatype/ssh_key_fingerprint"
---

# SSH key fingerprint (`ssh_key_fingerprint`)

> **Draft.** Draft records have not been reviewed yet and may be incomplete or wrong; do not treat them as authoritative for legal or compliance decisions.

Fingerprint of an SSH public key, as printed by ssh-keygen -l and shown when a client first connects to a host: SHA256: and 43 characters of unpadded Base64 (the default since OpenSSH 6.8), or the legacy MD5 form of 16 colon-separated hexadecimal octets, optionally after MD5:.

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

## Detection

Regular expression (Python `re`):

```
^(?:SHA256:[A-Za-z0-9+/]{43}|(?:MD5:)?[0-9a-f]{2}(?::[0-9a-f]{2}){15})$
```

## Examples

- `SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU` — Fingerprint of the Ed25519 host key of github.com
- `SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s` — Fingerprint of the RSA host key of github.com
- `MD5:65:96:2d:fc:e8:d5:a9:11:64:0c:0f:ea:00:6e:5b:bd` — Legacy MD5 fingerprint of the Ed25519 host key of github.com (ssh-keygen -E md5)
- `AE:C4:60:61:F4:58:FC:B5:6E:20:4A:11:79:DE:BB:CF:23:7F:1C:53` (invalid example) — SHA-1 fingerprint of an X.509 certificate (20 octets)

## Sources

- doc: <https://man.openbsd.org/ssh-keygen>
- other: <https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/githubs-ssh-key-fingerprints>
- wikipedia: <https://en.wikipedia.org/wiki/Public_key_fingerprint>

## Quality

Score 75/100. Missing: mapping (Wikidata, Schema.org, ...), translation, detector coverage.

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