On Wed, 1 Oct 2014, Valeri Galtsev wrote:
On Wed, October 1, 2014 11:34 am, Nicolas Thierry-Mieg wrote:
On 10/01/2014 06:07 PM, Valeri Galtsev wrote:
On Wed, October 1, 2014 10:19 am, Nicolas Thierry-Mieg wrote:
On 10/01/2014 05:16 PM, Nicolas Thierry-Mieg wrote:
On 10/01/2014 04:58 PM, Tim Dunphy wrote:
Hey guys,
Having a little gpg issue I was wondering if someone could help me
with.
A friend of mine sent me an encrypted message. So I searched
online
and
found a a set of keys that correspond with his email address. And
imported
them. But when I go to decrypt the message, this is what I get:
[root@ops:~] #gpg --decrypt roger-message
gpg: encrypted with 2048-bit RSA key, ID 9617EA5C, created 2014-10-01
"Roger Sherman <rsherman@xxxxxxxxxxx>"
*gpg: encrypted with RSA key, ID 9A41C766*
*gpg: decryption failed: secret key not available*
<snip>
So maybe I just didn't import the right key? Or do you think the
message
wasn't sent correctly? Who's the dummy here? Me or him? :)
looks like he encrypted with HIS public key. So you need his private
key
to decrypt, obviously you don't have that.
I believe it's the other way around: he should encrpyt with your
public
key, then you are the only person capable of decrypting (with your
private key).
BTW what would be the point of encrypting, if anyone can just grab a
key
online and decrypt? :-)
If you can decrypt his message with his public key, this tells you that
the person who has access to secret key of the pair was the one who
encrypted the message. This ensures that you know that he is the one who
indeed sent this message.
that is the purpose of *signing*: authenticate the sender and prevent
tampering of the message.
The purpose of *encrypting* is different: make sure only the intended
recipient can read (decrypt) the message.
Sometimes you do both, but you don't have to.
Sure, I agree, but I just answered the question if encrypting with one's
own secret key is nonsense, which it isn't, but normally people do what
you describes, and that is the way was pgp and gpg are meant to be used...
still "unusual thing" as encrypting with one's own private key isn't
nonsense.
Valeri
++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++
This thread has turned in to 'cryptography 101' on the CentOS mailing
list. This is my last post...
Encrypting content (a message) with ones own secret key with the intent of
privacy is pointless (or nonesense as you say). With the premise being
that the 'matching' key to that secret key is, well, public or accessible
to anyone. Hense no privacy as the content can be decrypted by anyone.
Encrypting a message digest or hash with ones own secret key makes perfect
sense. That is the essence of a digital signature.
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