mailing list archives
Re: stealing ssh keys
From: "Raj Mathur (राज माथुर)" <raju () linux-delhi org>
Date: Sat, 27 Oct 2012 08:19:04 +0530
On Thursday 25 Oct 2012, Ivaylo Hubanov wrote:
You almost got the RSA encryption/decryption flow. :) Just the
private key is used to sign the data and not to encrypt it.
We're splitting hairs here :) but the private key is actually used to
encrypt. That encryption is called a signature.
Except, what you encrypt with the private key is a digest of the
message, not the whole message itself. When your recipient gets the
message with the encrypted digest, she uses the same algorithm to make
her own digest of the received message. She then uses your public key
to decrypt the encrypted digest you'd sent and compares the two digests.
If they're the same, then (a) the message originated from you, and (b)
the message was not tampered with during transmission.
If they're not the same, then someone is playing silly buggers in the
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