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| author | ubbo <ubbo@34ebc366-c3a9-4b3c-9f84-69acf7962910> | 2012-02-04 18:02:53 +0000 |
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| committer | ubbo <ubbo@34ebc366-c3a9-4b3c-9f84-69acf7962910> | 2012-02-04 18:02:53 +0000 |
| commit | 3488ad4a740695fb8bda85203e8fb4a3d89343a0 (patch) | |
| tree | 5fd4d757667ac4df595f6db187ee48fdf8e1235b /release/help | |
| parent | new style for choose page (diff) | |
| download | gpg4usb-3488ad4a740695fb8bda85203e8fb4a3d89343a0.tar.gz gpg4usb-3488ad4a740695fb8bda85203e8fb4a3d89343a0.zip | |
add conpets docu from gpg-mini-howto
git-svn-id: http://cpunk.de/svn/src/gpg4usb/trunk@788 34ebc366-c3a9-4b3c-9f84-69acf7962910
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| -rw-r--r-- | release/help/docu_concepts.html | 129 |
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diff --git a/release/help/docu_concepts.html b/release/help/docu_concepts.html new file mode 100644 index 0000000..fbfe8ca --- /dev/null +++ b/release/help/docu_concepts.html @@ -0,0 +1,129 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de" lang="de"> + +<head> +<title>gpg4usb - Documentation</title> +<link rel="stylesheet" type="text/css" href="css/style.css" media="screen" /> +<link rel="stylesheet" type="text/css" href="css/print.css" media="print" /> +</head> + +<body> + +<div style="width:800px;text-align:center;float:center"> +<a href="docu.html">Main</a> | Next: <a href="docu_keygen.html">Generating A Key</a> +<hr/> + +<div id="content"> + +<H2><A NAME="GPG-Minihowto-Concept"></A> <A NAME="s1">1.</A>Concepts</H2> +<H2><A NAME="ss1.1">1.1</A> Public Key Encryption +</H2> +<P>Classic methods for encryption only use one key for encryption. The sender +encrypts the message with this key. To be able to decrypt this the receiver +needs to have this very same key. This key must have been given to the +receiver in a way, that others won't have had the opportunity to obtain this +key. If somebody else does have the key, this method of encryption is useless.</P> +<P>The use of so-called Public Keys can solve this problem. Public Keys is a +concept where two keys are involved. One key is a Public Key that can be +spread through all sorts of media and may be obtained by anyone. The other +key is the Private Key. This key is secret and cannot be spread. This key is +only available to the owner. When the system is well implemented the secret +key cannot be derived from the public key. Now the sender will crypt the +message with the public key belonging to the receiver. +Then decryption will be done with the secret key of the +receiver.</P> +<P>Crucial in this concept is that the secret key remains a secret and should +not be given away or become available to anyone else but the owner of this +key. YOU CANNOT SEND THIS KEY OVER THE INTERNET. Also it is very unwise to +use GnuPG over <CODE>telnet</CODE> (you might consider never to use telnet based +on the high security risks).</P> +<H2><A NAME="ss1.2">1.2</A> Digital Signatures +</H2> +<P>In order to prove that a message was really sent by the alleged sender the +concept of Digital Signatures was invented. As the name says a message is +digitally signed by the sender. By using this signature you can check the +authenticity of a message. Using this will reduce the risk for Trojan horses +(a message that claims to be a patch to a certain problem but actually contains +a virus or does something bad with data on your computer). Also information or +data can be verified as coming from a legitimate source and thus be regarded +as real.</P> +<P>A digital signature is made through a combination of the secret key and the +text. Using the senders public key the message can be verified. Not only will +be checked if the correct sender is involved, also the content will be checked. +So you know that the message comes from the sender and has not been changed +during the transportation process.</P> +<H2><A NAME="ss1.3">1.3</A> Web of trust +</H2> +<P>A weak point of the Public key algorithms is the spreading of the public keys. +A user could bring a public key with false user ID in circulation. If with +this particular key messages are made, the intruder can decode and read the +messages. If the intruder passes it on then still with a genuine public key coded to the +actual recipient, this attack is not noticeable.</P> +<P>The PGP solution (and because of that automatically the GnuPG solution) +exists in signing codes. A public key can be signed by other people. This +signature acknowledges that the key used by the UID (User Identification) +actually belongs to the person it claims to be. It is then up to the user of +GnuPG how far the trust in the signature goes. You can consider a key as +trustworthy when you trust the sender of the key and you know for sure that +the key really belongs to that person. Only when you can trust the key of the +signer, you can trust the signature. To be absolutely positive that the key is +correct you have to compare the finger print over reliable channels before +giving absolute trust.</P> +<H2><A NAME="ss1.4">1.4</A> Boundaries to security +</H2> +<P>If you have data that you would like to remain confidential, there is more to +it than just determining which encoding algorithm to use. You should be thinking +about your system security in general. Basically we consider PGP to be secure +and as I write this documents no incidents of PGP being cracked are known to me. +But that doesn't mean that all encoding must be safe then (for instance the NSA +wouldn't notify me if they cracked PGP somehow, neither would other people who +crack for real malicious grounds). But even if the PGP is fully 'unhackable', +other means can be used to attack the security. Early February 1999 a Trojan Horse had +been found that searched for secret PGP keys on the hard disk and FTP-ed them +away. If the password has been chosen badly the secret key can easily be +cracked.</P> +<P>Another technical possibility (although more difficult) is a Trojan Horse that +broadcasts keyboard entries. Also possible (but very difficult) is to pass +the content of a screen along. Then no cracking of scrambled messages needs to +be done. For all these risks there need to be a good, well-thought security plan +that is actually deployed.</P> +<P>It is not a goal to create paranoia among people, but to point out that a lot +needs to be done to be more secure. The most important thing is to realize that +encryption is just one step to security and is not a total solution. Trojan +horses as they appeared in the Melissa virus in March 1999 proved that many +companies are not prepared for that.</P> + + +<hr> + +<p> +Disclaimer: this chapter originates from the <a href="http://www.gnupg.org/documentation/howtos.html">GnuPG MiniHOWTO</a> +</p> +<p> +Copyright © 1999 Brenno J.S.A.A.F. de Winter (English version) Copyright © 1999 +Michael Fischer v. Mollard (original German version) Copyright © 2002 Arjen Baart +(Dutch version) Copyright © 2004 Baris Cicek (Turkish version) +</p><p> +This document is free documentation you can redistribute it and/or modify it under +the terms of the GNU Library General Public License as published by the Free +Software Foundation; either version 2 of the License, or (at your option) any +later version. +</p><p> +This library is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A +PARTICULAR PURPOSE. See the GNU Library General Public License for more details. +</p><p> +You should have received a copy of the GNU Library General Public License along +with this library; if not, write to the Free Software Foundation, Inc., 59 Temple +Place - Suite 330, Boston, MA 02111-1307, USA. +</p> +</hr> + +</div> +<hr/> +<a href="docu.html">Main</a> | Next: <a href="docu_keygen.html">Generating A Key</a> +</div> +</body> +</html> + |