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I'm using signtool to sign my windows binaries and using Digicert's timestamp server http://timestamp.digicert.com

I noticed that most of the timestamp server are hosted on HTTP. Isn't it less secure than HTTPS?

Are the timestamp responses signed and signtool verifies that responses are not tampered with?

GAR
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    Yes 'trusted' timestamps are signed, see RFC3161. I don't know if signtool verifies it, but more importantly every time for the next 5 or 10 or 20 years that anyone runs this program, the _OS_ verifies the timestamp signature before trusting it to affirm the code signature, because even if _you_ attach a valid timestamp and signature, someone could later replace them with bogus ones and harmful code. – dave_thompson_085 May 02 '20 at 04:45

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Providing an unauthenticated Time Stamp service over HTTP is not less secure than HTTPS because you don't send any user/password to access the TSA service.

Moreover the authenticity of the message is already provided by the TSA signature (and client should verify it).

If you are publishing a software binary you don't have a privacy concern regarding the hash. But we can figure out situations where nobody have to know you own the document ot that you are timestamping it.

Anyway the hash of your file that you are sending is produced with a nonce. The aim of using a nonce is to verify the timeliness of the response and avoid reply attacks, as explained in paragraph 2.4.1 of RFC3161, but the side effect is enhanced privacy too.

cisba
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