Without knowing too much background on where the need arises I had a quick conversation with one of our customers regarding e-mail encryption. Here is basically what they need:
- End to end e-mail encryption and signing
- Should work with any mail server systems and e-mail client
- Should be as cost effective as possible
- Will be only for a very small subset of users of approx. 5-10 users
The way I understand it there is basically 4 options:
1. S/MIME
2. TLS
3. Hosted Services
4. IRM
IRM sound the most promising in terms of feature set but does not have the ability to send IRM protected content to external recipients.
S/MIME also sounds very good in terms of feature but they way I understand it cannot be controlled centrally and it also cannot be used together with IRM?
Please correct me if I am wrong and maybe offer some more insight. Below are the links I used for reference:
http://technet.microsoft.com/en-us/library/dd638140
http://technet.microsoft.com/en-us/library/aa995740(EXCHG.65).aspx