Getting an SMIME certificate: Difference between revisions

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==Certificate Authorities==
==Certificate Authorities==
===Sources of Free SMIME Certificates===
===Sources of Free SMIME Certificates===
Free SMIME certificates are available from:
Free certificates usable for [http://en.wikipedia.org/wiki/S/MIME S/MIME] are available from:
*[http://www.thawte.com/email/index.html Thawte]
 
*[https://www.verisign.com/products-services/security-services/pki/pki-application/email-digital-id/page_dev004002.html Verisign]
*[https://www.cacert.org/index.php?id=1 <S>CAcert</S>] (CAcert is NOT one of the trusted authorities built-in to FireFox and ThunderBird. The connection is also untrusted)
*[http://www.instantssl.com/ssl-certificate-products/free-email-certificate.html InstantSSL / Comodo]  
*[http://www.instantssl.com/ssl-certificate-products/free-email-certificate.html InstantSSL / Comodo]  
*[http://www.trustcenter.de/en/products/tc_certificates.htm TC TrustCenter] and [http://www.chosensecurity.com/products/tc_certificates.htm ChosenSecurity]
*[https://www.globalsign.com/document-security-compliance/microsoft-office-document-security/ GlobalSign] (free 30-day trial)
*[http://certs.ipsca.com/Products/SMIME.asp ipsCA]
*[https://www.secorio.com/index.php?S_MIME_Email_Certificates Secorio]  
*[https://www.cacert.org/index.php?id=1 CAcert] (CAcert is NOT one of the trusted authorities built-in to FireFox and ThunderBird)
*[https://cert.startcom.org/ <S>StartCom</S>] (StartCom certificates have been revoked by Mozilla)  
*[https://cert.startcom.org/?app=101&type=1 StartCom]
 
====Free Certificates from Comodo====
Comodo has perhaps one of the easiest [https://secure.comodo.com/products/frontpage?area=SecureEmailCertificate procedures] for requesting a certificate. They are free, good for a year, can be picked up in most browsers, and in any key length.
 
====Free Certificates from Thawte====
You can get a free [http://en.wikipedia.org/wiki/S/MIME S/MIME] certificate from [http://www.thawte.com/email/index.html Thawte]. Like most free certificates, it is bound to your email only and not your name, which will only show as ''Thawte Freemail Member''. By participating in the free Thawte [http://www.thawte.com/en/secure-email/web-of-trust-wot/index.html ''Web of Trust''] (WOT), you can have others verify your identity from your legal documentation, allowing you to bind your real name to your certificate. From then on, you can use your certificate alone to verify your identity (to those who know what it means and choose to accept it.)


Oddly, Thawte's free certs do not include CRL link fields, so revocation will not typically be detected by recipients. (They would have to manually configure Thunderbird to check CRL lists which they will first have to find.) Revocation is an important piece of public key infrastructure security so this is an unfortunate shortcoming.
Some of them are free only for personal use. It can also cost money to revoke a free certificate. [http://www.techdirt.com/articles/20140409/11442426859/shameful-security-startcom-charges-people-to-revoke-ssl-certs-vulnerable-to-heartbleed.shtml]


====Free Certificates from Verisign====
Let's Encrypt does not offer S/MIME certificates. See https://community.letsencrypt.org/t/s-mime-certificates/153 for a thread explaining why you can't use their SSL/TLS certificates for S/MIME.
Alternatively you can get a similar free certificate from [https://www.verisign.com/products-services/security-services/pki/pki-application/email-digital-id/index.html VeriSign] - just click the buy button and choose the free option. Note that the free certificate is good for 60 days while the paid-for one (20USD) lasts a year. VeriSign runs a free LDAP service that is compatible with Netscape, Mozilla, Thunderbird, Outlook, and Outlook Express so your friends can look-up your certificate automatically while composing email to send you encrypted email.


===To obtain certificate from an authority===
===To obtain certificate from an authority===
Browsers such as Firefox, MSIE, Opera, Safari and so forth contain cryptotools capable of generating public/private keypairs. When signing up for a certificate with an authority, their website triggers your browser to create a keypair and transmit to them the public key, which is then certified. For this reason, when you return to pick up your completed certificate (typically a few minutes later), it is mandatory that you do so with ''' ''the same browser on the same computer'' '''. You will othewise not possess the private key necessary for pickup.
Browsers such as Firefox, MSIE, Opera, Safari and so forth contain cryptotools capable of generating public/private keypairs. When signing up for a certificate with an authority, their website triggers your browser to create a keypair and transmit to them the public key, which is then certified. For this reason, when you return to pick up your completed certificate (typically a few minutes later), it is mandatory that you do so with ''' ''the same browser on the same computer'' '''. You will otherwise not possess the private key necessary for pickup.


It will then still be necessary to export the resulting new key and certificate to a regular but password protected file that can then be imported into Thunderbird's certificate store. The CA's and/or your browsers help files should explain how to export your new certificate and keys.
It will then still be necessary to export the resulting new key and certificate to a regular but password protected file that can then be imported into Thunderbird's certificate store. The CA's and/or your browsers help files should explain how to export your new certificate and keys.


To import the exported keys into Thunderbird,  "Tools -> Options -> Advanced -> Encryption -> View Certificates -> Import".
To export it as a .p12 (Personal Information Exchange File) file using Firefox go to [[Menu differences in Windows, Linux, and Mac|Tools -> Options]] -> Advanced -> Encryption -> View Certificate and select the certificate. Then press the backup key. You will be prompted for a password which you will have to enter when you import the file.
 
To import the file  into Thunderbird,  use "[[Menu differences in Windows, Linux, and Mac|Tools -> Options]] -> Advanced -> Encryption -> View Certificates -> Import". You will be prompted for the password you used when you exported (or backed up) the file.


Once you have imported your certificate into Thunderbird, it will then be available for pairing with one or more accounts in Thunderbird. Account Settings -> Security -> Select.
Once you have imported your certificate into Thunderbird, it will be available for pairing with one or more accounts in Thunderbird using Tools -> Account Settings -> Security -> Select.


Be thoughtful about whether to select to "digitally sign all messages by default". Institutional firewalls may protect their own security protocols and break your cryptographic signature, leaving your recipient with all kinds of warnings about the message being invalidly signed. As S/MIME usage is still not widespread, most people still don't know how to interpret this. A broken signature will probably seem worse to them than receiving a message with no crypto signature at all, even though the contents are identical in both cases.
Be thoughtful about whether to select to "digitally sign all messages by default". Institutional firewalls may protect their own security protocols and break your cryptographic signature, leaving your recipient with all kinds of warnings about the message being invalidly signed. As S/MIME usage is still not widespread, most people still don't know how to interpret this. A broken signature will probably seem worse to them than receiving a message with no crypto signature at all, even though the contents are identical in both cases.


Webmail users will see an unreadible attachment which can raise simliar questions.
Webmail users will see an unreadable attachment which can raise similar questions.


==Self-signed certificates==
==Self-signed certificates==
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* ''Adobe Acrobat'' for signing and encrypting pdf documents. This requires the non-free ''Acrobat'' to generate. The free ''Adobe Reader'' is available to decrypt and verify.
* ''Adobe Acrobat'' for signing and encrypting pdf documents. This requires the non-free ''Acrobat'' to generate. The free ''Adobe Reader'' is available to decrypt and verify.
* ''OpenOffice'' also contains some signing capability using certificates.
* ''OpenOffice'' also contains some signing capability using certificates.
These have the advantage over ''S/MIME'' in that they pass more easily through firewalls, but at the price of requiring more effort to generate.
These have the advantage over ''S/MIME'' in that they pass more easily through firewalls, but at the price of requiring more steps to generate.


==See also==
==See also==

Revision as of 07:39, 22 September 2017


Certificate Authorities

Sources of Free SMIME Certificates

Free certificates usable for S/MIME are available from:

Some of them are free only for personal use. It can also cost money to revoke a free certificate. [1]

Let's Encrypt does not offer S/MIME certificates. See https://community.letsencrypt.org/t/s-mime-certificates/153 for a thread explaining why you can't use their SSL/TLS certificates for S/MIME.

To obtain certificate from an authority

Browsers such as Firefox, MSIE, Opera, Safari and so forth contain cryptotools capable of generating public/private keypairs. When signing up for a certificate with an authority, their website triggers your browser to create a keypair and transmit to them the public key, which is then certified. For this reason, when you return to pick up your completed certificate (typically a few minutes later), it is mandatory that you do so with the same browser on the same computer . You will otherwise not possess the private key necessary for pickup.

It will then still be necessary to export the resulting new key and certificate to a regular but password protected file that can then be imported into Thunderbird's certificate store. The CA's and/or your browsers help files should explain how to export your new certificate and keys.

To export it as a .p12 (Personal Information Exchange File) file using Firefox go to Tools -> Options -> Advanced -> Encryption -> View Certificate and select the certificate. Then press the backup key. You will be prompted for a password which you will have to enter when you import the file.

To import the file into Thunderbird, use "Tools -> Options -> Advanced -> Encryption -> View Certificates -> Import". You will be prompted for the password you used when you exported (or backed up) the file.

Once you have imported your certificate into Thunderbird, it will be available for pairing with one or more accounts in Thunderbird using Tools -> Account Settings -> Security -> Select.

Be thoughtful about whether to select to "digitally sign all messages by default". Institutional firewalls may protect their own security protocols and break your cryptographic signature, leaving your recipient with all kinds of warnings about the message being invalidly signed. As S/MIME usage is still not widespread, most people still don't know how to interpret this. A broken signature will probably seem worse to them than receiving a message with no crypto signature at all, even though the contents are identical in both cases.

Webmail users will see an unreadable attachment which can raise similar questions.

Self-signed certificates

You may use a personally self-signed certificate in Thunderbird. However, since these certificates are not signed by an approved certificate authority, the certificate will not be trusted by other computers or people unless they add the self-signed certificate to their list of certificate authorities. Personally self-signed certificates are generally only useful for testing or for exchanging information with people you already know and trust.

It's possible to generate self-signed certificates using the Firefox Add-on Key Manager: Tools - Key Manager Toolbox - Key Manager - Your Keys - Generate SelfSign Cert and insert you data. On tab Advanced - Standard X.509 Extensions check "Is CA?".

Another option for those who have sufficient understanding of certificate structures is using the command line OpenSSL.

Special considerations for installing personally self-signed certificates can be found in the Installing an SMIME certificate article.

Self-signed certificates in Mac OS X 10.4

You can create your own self-signed certificate using the Keychain Access application's Certificate Assistant. To export your certificate as a PCKS12 file for import into Thunderbird, click "My Certificates" in the Keychain Access window. Select your self-signed certificate. Then from the menu bar select "File -> Export". You will be asked for a password to protect this file. This is the password you will require when importing the certificate into the "Your Certificates" tab of Thunderbird after entering your master password.

To export your certificate as a ".cer" file for use as a certificate authority, select "Certificates" in the Keychain Access window. Select your self-signed certificate. Then from the menu bar select "File -> Export". Be sure ".cer" is selected as the appropriate file type in the save dialog.

Other uses for certificates

Free certificates are not necessarily limited to use only by S/MIME email. The same digital id's can be imported and employed during document generation, for example, by ...

  • Adobe Acrobat for signing and encrypting pdf documents. This requires the non-free Acrobat to generate. The free Adobe Reader is available to decrypt and verify.
  • OpenOffice also contains some signing capability using certificates.

These have the advantage over S/MIME in that they pass more easily through firewalls, but at the price of requiring more steps to generate.

See also

External links