[seahorse/wip/userdocs: 15/244] help: Update introduction.page

[Ekaterina Gerasimova <egerasimov src gnome org>]

commit 9d36f2f0b6cfa6d8505de84a5135f3f10713fd48
Author: Aruna Sankaranarayanan <arunasank src gnome org>
Date:   Mon Jun 17 22:08:00 2013 +0530

    help: Update introduction.page

 help/C/introduction.page |   30 +++++++++++++++++-------------
 1 files changed, 17 insertions(+), 13 deletions(-)
---
diff --git a/help/C/introduction.page b/help/C/introduction.page
index 67d1c3a..ef13202 100644
--- a/help/C/introduction.page
+++ b/help/C/introduction.page
@@ -27,36 +27,40 @@
   <title>Introduction</title>
 
   <p><app>Passwords and Keys</app> helps you to communicate securely over the
-  Internet and keep your files and data safe. It provides extremely advanced
-  mathematical methods and highly secret keys to protect your files and
-  communication. Some basic terms that you may encounter while reading this
-  help are:</p>
+  Internet and keep your files and data safe. It provides advanced mathematical
+  methods and secret keys to protect your files and communication. Some basic
+  terms that you may encounter while reading this help are:</p>
 
   <terms>
     <item>
       <title>Encryption</title>
-       <p>Encryption is the process of making your important files and data
+        <p>Encryption is the process of making your important files and data
        unreadable to anyone but the intended recipient. It is done by the
        sender.</p>
     </item>
     <item>
+      <title>Algorithm</title>
+       <p>An algorithm is a sequence of steps used to encrypt or decrypt
+       data</p>
+    </item>
+    <item>
       <title>Decryption</title>
-       <p>Decryption is the process of retrieving the original text from the
+        <p>Decryption is the process of retrieving the original text from the
        encrypted message or file. It is done by the receiver.</p>
     </item>
     <item>
       <title>Plaintext</title>
-       <p>Any data or file that is readable by a recipient or a
-       non-recipient.</p>
+        <p>Any data or file that is not encrypted, and therefore understood by
+       anyone who can access it, is called plaintext.</p>
     </item>
     <item>
       <title>Key</title>
        <p>A key is used to encrypt or decrypt your data. For example, if you
-       wish to encrypt your personal messages by substituting every letter in
-       the message with a new letter according to some substitution set you
-       have, the substitution set would be a key because anyone who has the
-       substitution set can decrypt your messages. <app>Passwords and
-       Keys</app> uses highly complex and advanced mathematical means to
+       wish to encrypt a personal message by substituting every letter in the
+       message with a new letter according to some substitution set you have,
+       the substitution set would be a key because anyone who has the
+       substitution set can decrypt your message. 
+       <app>Passwords and Keys</app> uses advanced mathematical means to
        generate a key so that it is not guessable. Keys can be
        <link xref="what-diff-private-public">private or public</link>.</p>
     </item>