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If S/MIME encryption is enabled in an outlook email, are attachments (e.g. an excel file) also protected while in transit between sender and recipient?
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Just checked in to see how things are going with this thread. You can click accept as answer if the posts below are helpful. If you would like further assistance on this, please feel free to post back.
S/MIME is not the same as the transport, but the message is digitally signed and encrypted in transit, yes.
The SMTP conversation between servers is also encrypted using TLS in most cases as well ( and can forced between domains if necesssary)
More on S/MIME
https://learn.microsoft.com/en-us/microsoft-365/compliance/email-encryption?view=o365-worldwide
If S/MIME encryption is enabled in an outlook email, are attachments (e.g. an excel file) also protected while in transit between sender and recipient?
As indicated in the Security settings, both message contents and attachments are encrypted.
