What is a .KEY file?
A .key file holds a cryptographic private or public key, used to secure connections and sign data.
- Did you know
- Keep private .key files secret - anyone holding one can impersonate you.
- A .key file is often PEM text - Base64 between “BEGIN” and “END” lines - which is just a wrapper around the binary DER key.
- The same .key extension is reused for many key types, from TLS server keys to PKCS#8 private keys, so contents vary widely.
- What Analyser reads
- Inspect security and crypto files: PEM private/public keys (RSA/EC/Ed25519, PKCS#1 vs PKCS#8, encryption), OpenSSH .pub with SHA-256 fingerprint, PuTTY .ppk, PKCS#10 CSR, X.509 CRL, PKCS#7 bundles, OpenVPN/WireGuard configs, Java KeyStores, Apple .mobileconfig/.mobileprovision, Windows .reg (with autorun flagging), and pcap/pcapng captures - warning when a private key or secret is present.
- Depth of analysis
- .KEY is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
- Open a .KEY file
- Drag a .KEY file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.