Guest guest Posted March 1, 2008 Report Share Posted March 1, 2008 ..P7S File Extension File Type Digitally Signed Message Category Text Files Common? No File Description Email message that includes a digital signature; can be used for sending secure emails that can only be viewed by the intended recipient; verifies that the email is from who it claims to be from and that the email has not been modified in transit 1c. I've received a CUHK e-mail with smime.p7s attachment and it said "This is an SMIME signed message". What does it mean? This means that it is a digitally signed message. You should open the digital certificate to check the identity of the sender. To improve security, all notifications that sent through the following ITSC systems will be signed with CUHK CA Certificates starting from. Jun 23 - ITSC Electronic HelpDesk (cumassmailing@...) Jul 7 - ITSC Accounts Information Management System (account-help@...) Jul 7 - ITSC Abnormal Network Traffic Alert System (resnet-help@...) Jul 14 - CU Mass Mailings (cumassmailing@...) You are strongly advised to install the CUHK Root CA Certificate. This allows browsers and e-mail applications to trust certificates issued by CUHK CA automatically, which saves you a lot of time. Please be aware that not all e-mail applications support this feature (e.g. Webmail). In such cases, you will receive emails with attachments such as smime.p7s (or p7m). Please read the following faq on how to vertify signed/encrypted messages in various e-mail applications. ===================================== Question Subject: p7s files Category: Computers Asked by: sj1960-ga List Price: $2.00 Posted: 22 Nov 2002 10:47 PST Expires: 22 Dec 2002 10:47 PST Question ID: 112659 How can a view a p7s file? Answer There is no answer at this time. Comments Subject: Re: p7s files From: funkywizard-ga on 22 Nov 2002 18:53 PST The file extentions website [ http://filext.com/p.htm ], links to a description of p7s from the rsasecurity website [ http://www.rsasecurity.com/rsalabs/pkcs/pkcs-7/index.html ]. It says that this format is assocaited with "PKCS #7 - Cryptographic Message Syntax Standard; This standard describes general syntax for data that may have cryptography applied to it, such as digital signatures and digital envelopes." I could not find a reader as such, so this is posted as a comment. Research strategy: https://answers.google.com/answers/main?cmd=search & q=file+extention & qtype=all Subject: Re: p7s files From: ness_ez-ga on 24 Nov 2002 02:33 PST This is a digital certificate (digital signature file). You can open in any e-mail reader, for example Outlook. But this file must be an attachment to e-mail to view it. You are probably using free e-mail service and read you mail trough web interface, if you'll access your mail trough POP protocol using Outlook (or similar program) you'll be able to view any further digitally signed e-mails as intended. Subject: Re: p7s files From: sparky4ca-ga on 17 Dec 2002 02:31 PST I have to agree. There are two ways you would commonly see a .p7s file. If somebody sends you a digitlly signed email, and you use a service or program such as hotmail that doesn't support tghem, then you'll see a small attachment of a p7s file. You may also see one if you export your digital certificate into a file in order to import it into another mail client. ===================================== S/MIME From Wikipedia, the free encyclopedia Jump to: navigation, search S/MIME (Secure / Multipurpose Internet Mail Extensions) is a standard for public key encryption and signing of e-mail encapsulated in MIME. Contents[hide] 1 History 2 Function 3 S/MIME Certificates 4 Obstacles to deploying S/MIME in practice 5 Caveats 6 See also 7 External links [edit] History S/MIME was originally developed by RSA Data Security Inc. The original specification used the recently developed IETF MIME specification with the de facto industry standard PKCS #7 secure message format. Change control to S/MIME has since been vested in the IETF and the specification is now layered on Cryptographic Message Syntax, an IETF specification that is identical in most respects with PKCS #7. [edit] Function S/MIME provides the following cryptographic security services for electronic messaging applications: authentication, message integrity and non-repudiation of origin (using digital signatures) and privacy and data security (using encryption). S/MIME specifies the application/pkcs7-mime (smime-type "enveloped-data") type for data enveloping (encrypting): the whole (prepared) MIME entity to be enveloped is encrypted and packed into an object which subsequently is inserted into an application/pkcs7-mime MIME entity. S/MIME functionality is built into the vast majority of modern e-mail software and interoperates between them. [edit] S/MIME Certificates Before S/MIME can be used in any of the above applications, one must obtain and install an individual key/certificate either from one's in-house certificate authority (CA) or from a public CA such as one of those listed below. Best practice is to use separate private keys (and associated certificates) for Signature and for Encryption, as this permits escrow of the encryption key without compromise to the non-repudiation property of the signature key. Encryption requires having the destination party's certificate on store (which is typically automatic upon receiving a message from the party with a valid signing certificate). While it is technically possible to send a message encrypted (using the destination party certificate) without having one's own certificate to digitally sign, in practice, the S/MIME clients will require you install your own certificate before they allow encrypting to others. A typical basic personal certificate verifies the owner's identity only in terms of binding them to an email address and does not verify the person's name or business. The latter, if needed (e.g. for signing contracts), can be obtained through CAs that offer further verification (digital notary) services or managed PKI service. For more detail on authentication, see Digital Signature. Depending on the policy of the CA, your certificate and all its contents may be posted publicly for reference and verification. This makes your name and email address available for all to see and possibly search for. Other CAs only post serial numbers and revocation status, which does not include any of the personal information. The latter, at a minimum, is mandatory to uphold the integrity of the public key infrastructure. [edit] Obstacles to deploying S/MIME in practice Not all e-mail software handles S/MIME, resulting in an attachment called smime.p7m that often confuses people. S/MIME is sometimes considered not properly suited for use via webmail clients. Though support can be hacked into a browser, some security practices require the private key to be kept accessible to the user but inaccessible from the webmail server, complicating the key webmail advantage of providing ubiquitous accessibility. This issue is not specific to S/MIME - any secure method of signing webmail requires a browser to execute code to produce the signature. Some organizations consider it acceptable for webmail servers to be "in on the secrets"; others don't. Some of the considerations are mentioned below regarding malware. Another argument is that servers often contain data that is confidential to the organization anyway, so what difference does it make if additional data, such a private keys used for decryption, are also stored and used on such servers? Many make a distinction between private keys used for decryption and those used for digital signatures. They are far more likely to accept sharing of the former than the latter. This is especially true if the non-repudiation aspect of digital signatures is a concern (it may not be). There is fairly universal consensus that non-repudiation requires that a private key be under sole control of its owner during its entire lifecycle. Ergo, it's more likely to accept decryption done with webmail servers than digital signatures. S/MIME is tailored for end to end security. Encryption will not only encrypt your messages, but also malware. Thus if your mail is scanned for malware anywhere but at the end points, such as your company's gateway, encryption will defeat the detector and successfully deliver the malware. Solutions: Perform malware scanning on end user stations after decryption. Store private keys on the gateway server so decryption can occur prior to the gateway malware scan. (Though this in some ways defeats the purpose of encryption, as it allows anyone with access to the gateway server to read another users mail.) Use message content scanners specifically designed to check the content of encrypted messages in transit whilst preserving end-to-end signatures and encryption. Such solutions must contain built-in protection for both the private key used to decrypt the message, and for the temporarily decrypted contents. [edit] Caveats When a message is encrypted using S/MIME (or PKCS#7), the public key of each intended recipient is extracted from their certificates and those certificates are identified in the message by issuer and serial number. One of the consequences of this is that if a certificate is renewed (i.e. new certificate, same keypair) and the old certificate is deleted thinking it won't be needed any more, S/MIME clients will no longer be able to locate the decryption key to decrypt messages sent before the renewal, even though the key hasn't changed. In other words, deletion of expired certificates can have surprising consequences. Even more generally, any messages that an S/MIME client stores in their encrypted form will not be decryptable if the certificate used for encryption has been deleted or otherwise not available, whether that certificate has expired or not. S/MIME signatures are usually done with what's called "detached signatures". The signature information is separate from the text being signed. The MIME type for this is multipart/signed with the second part having a MIME subtype of application/(x-)pkcs7-signature. Mailing list software is notorious for changing the textual part and thereby invalidating the signature. [edit] See also Cryptography Portal MIME Multipurpose Internet Mail Extensions TLS Transport Layer Security, formerly SSL E-mail authentication E-mail encryption Pretty Good Privacy (PGP) GnuPG [edit] External links S/MIME working group charter — has links to S/MIME related RFCs and internet drafts. How to forge an S/MIME signature — critique on some S/MIME implementations. S/MIME IETF Working Group S/MIME and OpenPGP MIMEBlackbox - components for Windows and .NET software developers with S/MIME and PGP/MIME support E-mail Client Testing for S/MIME Compliance VeriSign's Public Directory (ldap://directory.verisign.com) MozillaZine Knowledge Base: Getting an SMIME certificate SMIME.org provides help and references to products and standards of email encryption. Directory of free and paid certificate authorities at the Open Directory Project Retrieved from "http://en.wikipedia.org/wiki/S/MIME" Categories: Cryptographic protocols | E-mail authentication -----Original Message-----From: [mailto: ] On Behalf Of NGuinn555@...Sent: Friday, February 29, 2008 5:44 PMTo: practiceimprovement1 Subject: file type questionOK computer experts -what type of file would the following be?smime.p7sThanks, Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 1, 2008 Report Share Posted March 1, 2008 This means that it is a digitally signed message. You should open the digital certificate to check the identity of the sender. > > > > > > > OK computer experts - > what type of file would the following be? > > smime.p7s > > Thanks, > -- Graham Chiu http://www.synapsedirect.com Synapse - the use from anywhere EMR. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 1, 2008 Report Share Posted March 1, 2008 Thank you SO much for being the other person besides me that doesn’t know this. Annie From: [mailto: ] On Behalf Of NGuinn555@... Sent: Friday, February 29, 2008 7:44 PM To: practiceimprovement1 Subject: file type question OK computer experts - what type of file would the following be? smime.p7s Thanks, Quote Link to comment Share on other sites More sharing options...
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