CODEWITHSUNDEEP
emaildigital-signature
aronp
aronp

Reputation: 799

Can someone resend a digitally signed email

If someone receives a copy of a digitally signed email, is there any way they can resend from their own account so that it still appears to be digitally signed by the original sender. i.e. if they resend an exact binary copy of the email will that appear to be signed?

Upvotes: 0

Views: 170

Answers (1)

David Schwartz
David Schwartz

Reputation: 182761

Yes. Since it still was digitally signed by the original sender, it will still appear to be signed by the original sender. It works the same way with physical signatures -- I can take a letter signed by someone else and mail it to you. The letter will still appear to be signed by the same person. I just can't tamper with the contents of the letter.

If this was not so, how could servers deliver the signed email to you? All they receive is a copy of the digitally signed email. And it's not like they have some account of their own that they can send them from. The resend an exact digital copy, and of course it still appears to be signed since it still is signed since digital copies are not distinguishable from originals.

... resend from their own account so that it still appears to be digitally signed by the original sender ...

Note that since the email will, as you said, still appear to have been signed by the original sender, and it was in fact signed by the original sender, there's no vulnerability or issue here.

Upvotes: 1

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