Questions tagged [smime]

S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for public key encryption and signing of MIME data. Its role is similar to PGP.

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gpgsm: Cannot import private key

For signing emails, I requested an S/MIME certificate using the German academic DFN service. AT the end of this process, I get a .p12 file (PKCS12). I can convert this file to PEM using openssl ...
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How do i combine both "PGP signature" and "S/MIME signature" in one email?

Two is always better than one! Is that possible? If yes, any idea what application and configuration should i use?
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Using S/MIME, can I make Mail on macOS prompt for credentials just once?

I configured S/MIME encryption and signing for Mail on macOS Monterey 12.2. Even when I'm not trying to do any sort of crypto operation, I get a prompt reading "macOS wants to make changes. Enter ...
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Why does S/MIME encryption requires the sender to have a certificate of his own while only the recipient's public key is used?

S/MIME encryption uses the recipients public key to encrypt an email. Upon receiving the encrypted message the recipient can decrypt it using the private key associated with the public key that was ...
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Encryption issues (emails being encrypted for sender, not receiver) in Microsoft Outlook for Microsoft 365 MSO (16.0.13628.20234) 64-bit using S/MIME

I am trying to setup email encryption functionality. I have created my own CA, 2 PFX certificates, and have signed the PFX certificates with the CA certificate. The setup on both machines seem to be ...
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Why Outlook client's S/MIME settings use SHA1 as the default Hash Algorithm for digital signing a message?

can someone tell why Outlook client S/MIME settings use SHA1 as the default Hash Algorithm? Doesn't that put the certificate private key to a risk when weak algorithm is used? Or am I ...
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S/MIME and Office 365

I am new to the topic and started to search on the web to understand how should I proceed. I basically need to add a certificate to sign the emails sent from the company I work with, using Office 365. ...
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Cipher + Public key - S/MIME implementation on MS Outlook

I'm trying to understand the S/MIME implementation, and maybe I'm wrong. I'm so stuck that I will try to explain ... Sign a mail works as I thought it would work. But, I supposed that when you send a ...
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How do I create an S/MIME 4.0 certificate with X25519 with OpenSSL?

S/MIME 4.0 as described in RFC8551 specifies: 2.2. SignatureAlgorithmIdentifier Receiving agents: MUST support EdDSA with curve25519 using PureEdDSA mode Sending agents: MUST support at least one ...
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Decrypting .p7m file

I have a .p7m file that I want to decrypt. It is encrypted with with my ca.pem file. I have my ca.crt, ca.pem and ca.key I tried several methods to decrypt it, for example: openssl smime -verify -...
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How can I reply to S/MIME signed messaged in Web Outlook (outlook.office.com) when using Firefox

Whenever I get an S/MIME signed message I have no problems reading it but I can not reply to it. Clicking on the Reply button does nothing. I understand that I can not sign the reply message but I do ...
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Mozilla Thunderbird not opening p7m attachment of encrypted emails

When I receive an encrypted and signed email in Thunderbird, I can only see smime.p7m file attachment and no message. Mozilla should automatically decrypt and display the message (provided I have ...
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Exchange 2010 Transport Rule with S/MIME

If we create a transport rule to block all emails sending out with .doc attachment, it seems that the rule won't work on email which is signed with S/MIME cert. The email sending out is just signed, ...
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Sending an encrypted and digitally signed email from Outlook to other webmail clients

The company I work for uses Microsoft Exchange 2016 for email and we have S/MIME certificates for email encryption and digital signatures. Encryption and signing works for other exchange users, but is ...
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Make macOS Mail.app to attach full certificate chain to mail

When I'm sending S/MIME mails from Microsoft Outlook, it attaches the full certificate chain to the out-going mail so that recipients can verify the signing key (similar to how TLS works). However, ...
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Can not decrypt encrypted S/MIME message

After I sent an S/MIME signed eMail to an insurance company, their exchange server picked up my S/MIME certificate and their reply was S/MIME encrypted. Before, they used my PGP public key to encrypt ...
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S/MIME signed email loses attachment

We have a small number of users who digitally sign (but don't encrypt) their email. When they send attachments, it usually works fine. However, when the recipient is using Outlook Mobile, all ...
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Make OS-X Mail to choose a certain certificate for S/MIME signature

I have been using Apple Mail and S/MIME for quite a while now. While I have been starting with a commercial certificate, I now decided to switch to a certificate from a dedicated CA (recognized by all ...
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How to decrypt an S/MIME encrypted email using openssl smime?

For some reason, I seem unable to find an answer to this basic question. I have received an encrypted S/MIME email, and I want to decrypt it using openssl smime. However, I assume I am unable to ...
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Outlook 2016 answering a signed (S/MIME) email does not work

I have an outlook with 2 email addresses. One is an exchangeaccount and one is gmail. The exchange one uses a S/MIME certificate to sign outgoing emails. The gmail one doesn't use the certificate. ...
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Create Intermediate CA that can issue Certificates?

I'm trying to create a CA and Intermediate CA for use in Office 365 signing/encryption purposes in Outlook. I've been able to follow a bunch of tutorials and with OpenSSL produce a CA and Intermediate ...
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how to use / import a Lotus Notes public key into Thunderbird

A colleague from abroad who uses Lotus Notes sent me his "internet certificate" (i.e. public key), so I could import it into my own e-mail client. Unfortunately I do not recognise the format (neither ...
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2 votes
1 answer
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Outlook 2016 freezes when sending SMIME signed messages

I have an Outlook 2016 instance linked to a Microsoft Exchange 2013 server, running on a Windows 2016 Standard Remote Desktop Server. Everything works fine, just when I send a S/MIME signed message, ...
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Outlook warns about expired sender certificate that wasn't expired when sending S/MIME mail

When opening an email that was signed with a certificate which is since expired, Outlook 2007 warns that the signature is "invalid or not trusted" (shown in German as "ungültig oder nicht ...
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2 answers
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Outlook 2016: Multiple accounts, certificates only for one

This question has ben asked before but yet never answered. I have set up my Outlook 2016 with three different Mail accounts: name@domain1.com (commertial, office365) name@hotmail.com (personal, ...
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6 votes
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How to decrypt a broken S/MIME message sent by Outlook?

Recently, I received an encrypted message sent by Outlook which I cannot decrypt. Thunderbird is printing following error message instead: Thunderbird cannot decrypt this message The sender ...
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How to encrypt E-Mails with S/MIME

I am considering to encrypt some of my mails using S/MIME v3.1, since my devices should support it. Now I wonder if there is a (command line) tool that could do that for me? I tried to google it, ...
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Lotus Notes: issue when import Symantec/Verisign certificate

In order to sign/encrypt Email I have installed Verisign S-Mime Certificate from Verisign and exported it from IE as a .pfx (PKCS #12). My problem is when I tried to import it in Security > My ...
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Outlook S/MIME certificate expiration

I am using a certificate in Outlook to encrypt and sign messages. Everything work great. My certificate is going to expire next year. The following is unclear to me: Should I get a new certificate, ...
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openssl smime message signing: why do I need a -certfile key?

Here is how one should sign a message with openssl smime? according to the docs openssl smime -sign -in in.txt -text -out mail.msg -signer mycert.pem \ -inkey mykey.pem -certfile mycerts.pem But ...
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S/MIME with GMail in Browser

So I have a S/MIME Certificate at StartSSL now. I can now use it in my Thunderbird on Ubuntu and Windows 7. But how can I configure my Browser(Chrome) to use my certificate(which is already imported ...
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Possible to change Outlook SMIME icon from RED to Blue?

Every SMIME clear signed message has a red icon located near the Urgent exclamation point as shown below. This is often confused with high priority, and sends the wrong subtle message. IMHO a red ...
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2 votes
1 answer
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Signing-milter / SMIME - how are this email signed incorrectly?

I have a problem with signing-milter (http://www.signing-milter.org). The problem is that the -b flag is required, and the -b flag is not recommended because it outputs non-RFC compliant email. ...
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S/MIME for Mac and iOS

I have been trying to generate S/MIME certificates for my MacOS and iOS devices and it does not seem to work. I have researched on this matter and it seems that keyUsage and extendedKeyUsage are ...
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2 votes
3 answers
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How to get GPG working with Outlook 2013?

My OS is Windows 8.1 Update 1 x64. I have Outlook 2013 and just installed GPG4Win (latest, 2.2.2, full version). When I now launch Outlook 2013, I still don't see any UI/options to setup certificates ...
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2 votes
1 answer
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OS X 10.10 Apple Mail not recognizing S/MIME certificate

After upgrading to Yosemite, Apple Mail no longer recognizes my S/MIME certificate. This was working in Mavericks. I've checked Keychain and the certificate is valid, even evaluated it as S/MIME for ...
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How can I add an LDAP directory to all Outlook profiles? (SMIME directory)

I need my Windows based Outlook users to be able to look up an SMIME certificate from this LDAP directory How can I automatically (via scripting or policy) modify an Outlook profile to include this?
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Emacs Gnus email decrypt smime without openssl

I use gnus for my email. Every once in a while, I receive an encrypted email; when I answer "yes" to Gnus offer to decrypt it, it responds smime-verify-region: No CA configured. Now, my workplace ...
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Outlook 2013: Multiple accounts, sign only mails from one account

I have two email accounts (Exchange) configured in Outlook. For one I have a S/MIME certificate configured which always signs the mails I send from this account. Problem now is that Outlook also ...
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Is it possible to use self-signed SMIME certs with Mutt?

I'm trying to use a self-signed SMIME key that my company has issued me with Mutt. However, when I try to import it with smime_keys I get the following. Couldn't identify root certificate! No root ...
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Can't S/MIME sign using OpenSSL even if "verify" suceeds

I have a client certificate in Chrome, that I used for logging into StartSSL. I exported it using pk12util to certfile.p12. Now I want to use it for signing with S/MIME. I converted the p12 file to ...
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3 votes
1 answer
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Can I sign my emails with both S/MIME and PGP/GPG?

And if it possible, is there any benefit from doing so in one order or the other? signWithSMIME(signWithPGP(message)) versus signWithPGP(signWithSMIME(message)) Also, are there any reason not to ...
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S/MIME email Public Certificate?

Is there a way to create a public certificate for a S/MIME email certificate? I would like to share the public key on my website so people can send me encrypted emails. However I can only find "...
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How does Outlook deal with temporary data encrypted with S/MIME?

We are using S/MIME to encrypt messages and their attachments and Outlook as email application. All documents sent in attachment are stored on an encrypted folder and should never be copied anywhere ...
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Any way to sign mails in Gmail with S/MIME?

i am using S/MIME to sign my mails in Thunderbird and Apple Mail on my iOS devices. But from time to time i also use the Gmail webmailer. Is there any working pluging for Mozilla Firefox to also sign ...
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Mailinglists in Thunderbird with S/MIME

I am looking for a solution to send encrypted mails to a (internal) mailinglist. To encrypt the mail to all the recipients, I need some way to tell Thunderbird what the recipients are. I was hoping ...
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2 votes
1 answer
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Does SMIME encrypt the subject matter?

I've recently acquired an SMIME certificate and installed it in Outlook 2013. I set my brother up to do the same. So I used his certificate to send him an encrypted mail. He had an out of office ...
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4 votes
2 answers
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Outlook 2013, multiple email accounts and encrypted email: Only last S/MIME settings used

I have multiple email accounts properly setup in Outlook 2013 (can send/receive fine otherwise). Lets say they are: user1@domain1.com user2@domain2.com user3@domain3.com All belong to me and I have ...
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