P7 is a certificate file for local and web-related applications. P7 file extension is usually marked either as P7C or P7B. P7 files use Base64 ASCII encoding for storing public key and single certificate or certificate chain.

P7 format is sometimes referred to as PKCS # 7 after the specification of this type certificate standard. P7 files are typically used by applications running in Microsoft Windows environment or written in Java.