.p12

What is a .p12 file?

P12 bundles a certificate, its private key, and the certificate chain in a single password-protected file.

Use caution
Type Security
By RSA Laboratories (PKCS#12 standard)
MIME application/x-pkcs12

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What is it

P12 (PKCS#12) is the format for moving certificates with their private keys between systems. It bundles everything needed for SSL/TLS — the certificate, the private key, and the intermediate certificate chain — into a single password-protected file. When you need to install an SSL certificate on a new server, import a code signing certificate, or back up your client certificate, P12 is usually the format.

The password protection is essential because the file contains the private key. Without the password, the file is useless. With it, someone has everything needed to impersonate the certificate holder. Treat P12 files and their passwords like crown jewels — separate them, transmit them through different channels, and delete them when no longer needed.

Apple and Windows both import P12 files natively. On Mac, double-click to import into Keychain. On Windows, double-click to start the Certificate Import Wizard. For server deployment, `openssl pkcs12 -in bundle.p12 -out cert.pem -nodes` extracts the certificate and key as PEM files.

Technical details
Full Name
PKCS#12 Certificate Bundle
MIME Type
application/x-pkcs12
Developer
RSA Laboratories (PKCS#12 standard)
Magic Bytes
30 82
Safety
.p12 requires caution. Contains private keys. Password-protected but handle with extreme care — anyone with the file and password has your certificate's private key.
What opens it
Keychain Access
FREE Mac
Windows Certificate Manager
FREE Windows
KeyStore Explorer
FREE Windows / Mac / Linux
FAQ
What's the difference between P12 and PFX?
They're the same format. .p12 is the PKCS#12 standard extension. .pfx (Personal Information Exchange) is Microsoft's name for the same format. The file contents are identical.
How do I extract the certificate and key from a P12 file?
`openssl pkcs12 -in bundle.p12 -out cert.pem -clcerts -nokeys` extracts the certificate. `openssl pkcs12 -in bundle.p12 -out key.pem -nocerts -nodes` extracts the private key.
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