Certificates file extensions
Digital certificate and cryptographic trust files used for identity, signing, and secure connections.
Total extensions in this category: 12
Extensions in Certificates
Explore the most searched extensions in this category.
- .pfx
Personal Information Exchange (PFX)
.pfx is a PKCS #12 (PFX) container used to bundle certificates and (often) the associated private key into a single, typically password-protected file for import/export between systems.
- .pem
PEM-encoded Certificate
.pem is a text-based container format commonly used to store X.509 certificates, certificate chains, and sometimes private keys in Base64 with BEGIN/END markers. It is widely used by TLS software such as OpenSSL and Apache HTTP Server.
- .p12
PKCS#12 Certificate Bundle
.p12 is a PKCS #12 (also called PFX) container used to bundle an X.509 certificate chain together with its corresponding private key, typically protected by a password. It’s commonly opened/imported by certificate/key management tools such as Apple Keychain Access and OpenSSL.
- .csr
PKCS #10 Certificate Signing Request
.csr files are certificate signing requests used to obtain an X.509 certificate from a certificate authority (CA). They commonly contain a PKCS #10 request encoded as PEM (text) or DER (binary) and can be inspected or generated with OpenSSL.
- .der
DER-encoded X.509 Certificate
.der files most commonly contain binary DER-encoded ASN.1 data, especially X.509 certificates. They are typically opened for inspection or conversion using certificate tools such as OpenSSL.
- .p7b
PKCS #7 Certificate Bundle (P7B)
.p7b is a PKCS #7 container most commonly used to bundle X.509 certificates (and sometimes certificate revocation lists) for import or exchange. It typically does not include a private key and is often used in S/MIME and certificate deployment workflows.
- .ac
X.509 Attribute Certificate
.ac most commonly refers to an X.509 Attribute Certificate (authorization certificate) used in PKIX systems to carry privileges/roles separately from an identity certificate.
- .p7s
PKCS #7 / S/MIME Digital Signature (detached signature)
.p7s files are PKCS #7 signature objects most commonly used as detached digital signatures for S/MIME-signed email. You typically open them by verifying the signature in an email client or by inspecting/verifying with OpenSSL.
- .p7c
PKCS #7 / CMS certificate container (certs-only SignedData)
.p7c is a PKCS #7/CMS container most commonly used to carry X.509 certificates (often a “certs-only”/degenerate SignedData structure). It’s typically opened or inspected with certificate tools or OpenSSL rather than a document viewer.
- .cer
X.509 Certificate File
.CER is most commonly an X.509 digital certificate file used to identify a website, person, device, or organization. It typically contains a public certificate (not a private key) and can be viewed/installed with built-in tools on major desktop operating systems.
- .crl
Certificate Revocation List
.CRL is a Certificate Revocation List file used in X.509 PKI to publish certificates that have been revoked. It’s typically opened with certificate tools (Windows Certificate Import Wizard) or inspected/converted with OpenSSL.
- .crt
Certificate File
.CRT most commonly contains an X.509 digital certificate (often PEM or DER encoded) used for TLS/SSL and trust chains. You typically open it with certificate tools (view/import) rather than “run” it like a document.