P7S File Documentation

Files with the P7S extension are simply an e-mail message that has been secured with a digital signature using Public-Key Cryptography Standard technology. Messages that have been secured with a digital signature prevent them from being modified by unauthorized persons, at the same time - this method of protection requires both the sender and the recipient to confirm their identity.

P7S format files are most often used when there is a fear that the electronically sent message may be intercepted by someone. Opening a file with the P7S extension requires an appropriate email client that supports this message encryption standard, such as Microsoft Outlook or Mozilla Thunderbird. The Apple Mail application also supports files in the P7S format.


Feature Value
File Extension .p7s
MIME Type application/pkcs7-signature
Encoding ASN.1 (Abstract Syntax Notation One)
Primary Use Digital Signature Verification
Standard PKCS #7 (Public-Key Cryptography Standards)
Software Compatibility Microsoft Outlook, Mozilla Thunderbird, Adobe Acrobat, etc.
Multi-Signature Support Yes
Verification Requirement Public Key of the Signer
Content Storage Does not store actual data, only the digital signature
Common Applications Secure Email, Legal Documents, Financial Transactions
Limitations Requires specialized software, does not store actual data