Difference between revisions of "Talk:1181: PGP"

Explain xkcd: It's 'cause you're dumb.
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:You may be confusing "ASCII armored" (which in OpenPGP speak is "a BASE64-encoded version of the signature or encrypted text") with the encoding of the actual data (which may also be BASE64, or it may be Quoted-Nonprintable, or it may be actual plain-text ASCII). This separation line signals that signature will be at the end, and that the mail will not be encoded in PGP-MIME, which pretty much requires that the signature is ASCII armored.[[Special:Contributions/195.144.91.202|195.144.91.202]] 12:03, 4 March 2013 (UTC)
 
:You may be confusing "ASCII armored" (which in OpenPGP speak is "a BASE64-encoded version of the signature or encrypted text") with the encoding of the actual data (which may also be BASE64, or it may be Quoted-Nonprintable, or it may be actual plain-text ASCII). This separation line signals that signature will be at the end, and that the mail will not be encoded in PGP-MIME, which pretty much requires that the signature is ASCII armored.[[Special:Contributions/195.144.91.202|195.144.91.202]] 12:03, 4 March 2013 (UTC)
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:I also agree that the explanation doesn't really explain the point. PGP does not only provide encryption (which is in some sense privacy), but also authentication. If I publish my public key, anyone can use it to verify an email I signed with my private key. The joke is about what really happens. The text says: "If you find a header, this indicates a signed message. You are pretty safe if you assume the mail is authentic." This is funny, because email signatures are still so uncommon that there actually is no need to fake it. If you fake an email, why faking a signature? Just don't sign it. The image text goes one step further saying that you're safer when you look at the bottom of the mail and look for some weird random characters. This is what the actual signature looks like, but of course, the only way to really authenticate the mail is to use the sender's public key to verify that the random characters are a real signature. --[[User:BKA|BKA]] ([[User talk:BKA|talk]]) 12:19, 4 March 2013 (UTC)

Revision as of 12:19, 4 March 2013

I don't really understand what's funny about this comic. 76.106.251.87 05:53, 4 March 2013 (UTC)

Perhaps the fact that an email is encrypted (or pretends to be) at all? Most emails aren't encrypted, or none of the ones I send or get are. :D 59.10.72.121 06:28, 4 March 2013 (UTC)
what is funny, is that nobody can read the signatures -- and therefore they a less than pointless, as the gives a false sense of security.

I think merely the fact that PGP is in the email itself suggests the sender of the email is probably just a big nerd and therefore can be trusted. -- 153.90.91.1 (talk) (please sign your comments with ~~~~)

Isn't it that those markers could very simply just have been typed in, rather than being part of the decryption system? DonGoat (talk) 07:41, 4 March 2013 (UTC)

With public key systems like PGP you need the public key of the other person to verify the authenticity of the message. Most people do not use PGP or do not know how it works or are just lazy. Some of those are convinced enough just by the outer looks of a signed email: The starting block and the jumbled chars at the end. It is like being impressed by a signature per se in real life without knowing what the one of the person you write to looks like. I think the allusion to pretty good is coincidental. Sebastian --178.26.118.249 08:11, 4 March 2013 (UTC)

Email client is supposed to automatically check the signature and report it's validity in a way which can't be counterfeited. Few if any do. On the other hand, how much do you really want to need the email is signed? Unless it's asking for password or something, which would be suspicious anyway ... (and in that case, you should reply by ENCRYPTED email. By definition, email encrypted with public key of someone you trust posted to attacker should be useless to him).
Personally, I don't PGP sign my emails because noone I'm regularly writting to would be able to verify the signature. -- Hkmaly (talk) 09:27, 4 March 2013 (UTC)

There is an interesting comparison to do with regular handwritten signature, as this is exactly how people check the authenticity of a handwritten signed document: check for a signature. If there is one, and if there is, even if you never saw a sample of that signature, trust it. However, as with cryptographic signature with an unknown key, this does rely one something: the fact that it is forbidden, and punishable, to counterfeit one's signature, even if it is badly done (as in: write a random signature, hoping that the recipient does not know the real signature of the alleged author). -- Elessar (talk) 09:02, 4 March 2013 (UTC)

I agree with the commenters above me and I think the explanation goes into the wrong direction. This cartoon has nothing to do with encryption, it's only about (cryptographically) signing an e-mail. PGP can do both, but whilst signing is done using your own secret PGP key, for encryption you must have the public key of the recipient, so they must already know how to use PGP (or GnuPG) and have it installed. The cartoon is about people who either do not have PGP installed in their e-mail program or are using a web mailer (like many) that cannot handle cryptographically signed messages. For them, the signature is useless, unless they believe that the mere existence of a signature is a proof that the message is authentic. Oh, and the explanation is wrong on the ASCII armor. If you read the RFC correctly, this separation line is used if you don't have ASCII armored text but plaintext. 128.7.3.55 09:40, 4 March 2013 (UTC)

You may be confusing "ASCII armored" (which in OpenPGP speak is "a BASE64-encoded version of the signature or encrypted text") with the encoding of the actual data (which may also be BASE64, or it may be Quoted-Nonprintable, or it may be actual plain-text ASCII). This separation line signals that signature will be at the end, and that the mail will not be encoded in PGP-MIME, which pretty much requires that the signature is ASCII armored.195.144.91.202 12:03, 4 March 2013 (UTC)
I also agree that the explanation doesn't really explain the point. PGP does not only provide encryption (which is in some sense privacy), but also authentication. If I publish my public key, anyone can use it to verify an email I signed with my private key. The joke is about what really happens. The text says: "If you find a header, this indicates a signed message. You are pretty safe if you assume the mail is authentic." This is funny, because email signatures are still so uncommon that there actually is no need to fake it. If you fake an email, why faking a signature? Just don't sign it. The image text goes one step further saying that you're safer when you look at the bottom of the mail and look for some weird random characters. This is what the actual signature looks like, but of course, the only way to really authenticate the mail is to use the sender's public key to verify that the random characters are a real signature. --BKA (talk) 12:19, 4 March 2013 (UTC)