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6
votes
1answer
85 views

Reading older mails signed with a certificate that has meanwhile expired

A few years ago I have used S/MIME certs to sign (and encrypt) my mails. The reason for which I stopped signing was the following: My (class 2) cert was issued on Jan. 1st 2008 (just a sample). It ...
2
votes
2answers
112 views

Can I buy a signing-valid certificate for internal use?

So now that I have to implement "secure transport" as defined by The Direct Project (not to mention reinventing a bunch of wheels, but that's another story for SO), I find myself staring down the ...
1
vote
3answers
150 views

S/MIME doesn't protect against a stolen password, right?

We're setting up S/MIME so that we can send encrypted emails. However, I have a bit of a stupid (and maybe obvious) question... If someone steals a password for either the sender or the receiver, ...
-2
votes
2answers
160 views

What was the Lavabit's backdoors to their customers' e-mails? [closed]

There has been some talk about the Lavabit's case. New info was published today, but not important. I'd like to know how Lavabit worked. First I thought they just did something with OpenPGP. Then I ...
3
votes
2answers
2k views

SMIME email decryption key with OpenSSL

I'd like to know if it's possible to use openssl command to retrieve and decrypt the key for encrypting/decryptig email content. I know I can decrypt the whole encrypted mail by something like this ...
0
votes
1answer
146 views

Detecting SMIME type using OpenSSL CMS

Is it possible to detect S/MIME content types (enveloped or signed) using OpenSSL CMS API? I would prefer to avoid pre-parsing S/MIME headers and let OpenSSL to detect whether message is signed or ...
0
votes
1answer
138 views

How do I determine S/MIME encryption used?

From what I understand it seems that S/MIME uses PKCS #7 which can handle various different types of encryption. How is the choice of encryption method made by the e-mail client and how do I know what ...
0
votes
1answer
126 views

How to fetch and update all my friend's keys? [closed]

Where can I upload a list of my friends and get a list of their keys found on keyservers? Here are some key servers: http://keyserver.ubuntu.com:11371/ http://pgp.mit.edu/ ...
2
votes
1answer
703 views

How do I share my S/MIME public key?

I have setup S/MIME encryption for my email address, and I'd like to allow people to download the public key from my website, rather than having to first receive an email from me. I want the public ...
1
vote
2answers
1k views

OpenSSL PKCS#7 vs. S/MIME

OpenSSL 1.0.1c onwards seems to offer CMS support. I have difficulty understanding the difference between smime and pkcs7. S/MIME specs are layered on PKCS#7 (so says Wikipedia). Now in openssl I ...
3
votes
1answer
396 views

What's a trustworthy S/MIME Certificate Provider that generates my private key in my browser?

I read this question on the process of generating a private S/Mime key. I looked at Comodo - which offer free e-mail certificates. I'm trying to find out whether Comodo generates the private ...
1
vote
1answer
69 views

Bootstrapping dual SMIME certificates for signing and encryption?

To maintain the non-repudiation property of signing while still having escrow for the encryption key, it's recommended to have a separate certificates (and pub-priv keys) for signing (say CertSign) ...
15
votes
3answers
356 views

What expectation of privacy is there with US-based vendors with the LavaBit and SilentCircle shutdown?

Lavabit hosts a secure messaging service that was recently shut down. Likewise SilentCircle has preemptively done the same thing with their email-based service. It seems that the justification for ...
2
votes
1answer
244 views

Why should I pay for an email S/MIME certificate?

There are quite a few SSL certificate companies out there that offer free email S/MIME certificates. There are also paid versions as well. I need about 6 email certificates for some company email ...
13
votes
3answers
725 views

Can a nation-state adversary perform a MITM attack by compelling a CA to issue them with fake certs?

As I understand it, with any encryption system based on a trust chain / CAs (eg SSL, TLS, S/MIME), it would be possible for a nation-state adversary (such as the NSA) to compel the CA to issue them ...
2
votes
3answers
507 views

Where to get/buy a CSR generated S/MIME certificate

I'm not sure if the question is eligable for this board as I ask for concrete service providers which can be kind of advertisement, but there is also technical issue involved, so I give it a try. My ...
8
votes
2answers
995 views

Obtaining an S/MIME certificate without disclosing my private key to the TTP

I would like to obtain a trusted S/MIME certificate, but all the certificate authorities I have asked so far generate the keypair on their server, sign the certificate and send me both the private key ...
1
vote
2answers
116 views

Why is S/MIME (instead of PGP) recommended for such an scenario?

A large MNC with approximately 50,000 employees, and with offices in Asia, Europe and North America. This MNC operates its own PKI environment, with a self-signed Certificate Authority based at its ...
1
vote
1answer
830 views

Can I use any ssl certificate to sign and encrypt AS2 message?

I'm absolutely new to this topic of ssl certificates, so please be patient with me. My task is to install an AS2 communication with some business partner. Therefore we need message signing and ...
1
vote
1answer
149 views

How to have Thunderbird include a root certificate?

An eMail signed via S/MIME also contains the X.509 certificate chain containing the public key in order to directly verify the signature (assuming its issuing CA is deemed trustworthy). The chain does ...
1
vote
1answer
250 views

PKCS#7 message constructed by our code, any weaknesses in the output?

We have this as the PKCS#7 encrypted message. We would like to open this up for review and analysis here, for people to poke holes. This sample is generated via test certificates and keys. The concern ...
0
votes
1answer
220 views

Does S/MIME provide means to propagate a certificate's revocation?

Can a revocation certificate for an old X.509 certificate be attached to an email in addition to a replacement certificate in such a way that the client user does not have to manually intervene? Or ...
4
votes
1answer
228 views

Apart from the lack of native Oultook support, why should one prefer S/MIME over PGP/MIME for email?

From my (still quite subjective) point of view, GnuPG/PGP is superior to SSL (or more specifically, PGP/MIME over S/MIME; maybe in other areas SSL is the better choice), e.g. due to the support of ...
4
votes
1answer
1k views

Which extensions to use for a S/MIME certificate?

Analogously to the SSL server certificate question, which extensions should I use for S/MIME, and should the CA be restricted somehow as well? (I'm using openssl, which at the moment creates CA and ...
2
votes
1answer
779 views

What Enhanced Key Usages are required for PKI infrastructure tasks? (OIDs for OSPF and CRL signing, etc)

I'm building a constrained PKI that specifies EKUs for the the entire hierarchy and want to document the OIDs required for PKI tree maintenance tasks. I understand that clients may not validate the ...
1
vote
2answers
238 views

S/MIME verification

I am getting emails with smime.p7s attachments. when I look at my mail on my Linux box, I can see base64 encoded block in mail body. I can extract that block and open it on Windows using certmgr and ...