| |
| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> |
| <html><head><title>Python: module gdata.Crypto.Protocol.AllOrNothing</title> |
| </head><body bgcolor="#f0f0f8"> |
| |
| <table width="100%" cellspacing=0 cellpadding=2 border=0 summary="heading"> |
| <tr bgcolor="#7799ee"> |
| <td valign=bottom> <br> |
| <font color="#ffffff" face="helvetica, arial"> <br><big><big><strong><a href="gdata.html"><font color="#ffffff">gdata</font></a>.<a href="gdata.Crypto.html"><font color="#ffffff">Crypto</font></a>.<a href="gdata.Crypto.Protocol.html"><font color="#ffffff">Protocol</font></a>.AllOrNothing</strong></big></big></font></td |
| ><td align=right valign=bottom |
| ><font color="#ffffff" face="helvetica, arial"><a href=".">index</a><br><a href="file:/usr/local/google/home/afshar/src/external-gdata-release/google3/src/gdata/Crypto/Protocol/AllOrNothing.py">/usr/local/google/home/afshar/src/external-gdata-release/google3/src/gdata/Crypto/Protocol/AllOrNothing.py</a></font></td></tr></table> |
| <p><tt>This file implements all-or-nothing package transformations.<br> |
| <br> |
| An all-or-nothing package transformation is one in which some text is<br> |
| transformed into message blocks, such that all blocks must be obtained before<br> |
| the reverse transformation can be applied. Thus, if any blocks are corrupted<br> |
| or lost, the original message cannot be reproduced.<br> |
| <br> |
| An all-or-nothing package transformation is not encryption, although a block<br> |
| cipher algorithm is used. The encryption key is randomly generated and is<br> |
| extractable from the message blocks.<br> |
| <br> |
| This class implements the All-Or-Nothing package transformation algorithm<br> |
| described in:<br> |
| <br> |
| Ronald L. Rivest. "All-Or-Nothing Encryption and The Package Transform"<br> |
| <a href="http://theory.lcs.mit.edu/~rivest/fusion.pdf">http://theory.lcs.mit.edu/~rivest/fusion.pdf</a></tt></p> |
| <p> |
| <table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section"> |
| <tr bgcolor="#aa55cc"> |
| <td colspan=3 valign=bottom> <br> |
| <font color="#ffffff" face="helvetica, arial"><big><strong>Modules</strong></big></font></td></tr> |
| |
| <tr><td bgcolor="#aa55cc"><tt> </tt></td><td> </td> |
| <td width="100%"><table width="100%" summary="list"><tr><td width="25%" valign=top><a href="operator.html">operator</a><br> |
| </td><td width="25%" valign=top><a href="string.html">string</a><br> |
| </td><td width="25%" valign=top></td><td width="25%" valign=top></td></tr></table></td></tr></table><p> |
| <table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section"> |
| <tr bgcolor="#ee77aa"> |
| <td colspan=3 valign=bottom> <br> |
| <font color="#ffffff" face="helvetica, arial"><big><strong>Classes</strong></big></font></td></tr> |
| |
| <tr><td bgcolor="#ee77aa"><tt> </tt></td><td> </td> |
| <td width="100%"><dl> |
| <dt><font face="helvetica, arial"><a href="gdata.Crypto.Protocol.AllOrNothing.html#AllOrNothing">AllOrNothing</a> |
| </font></dt></dl> |
| <p> |
| <table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section"> |
| <tr bgcolor="#ffc8d8"> |
| <td colspan=3 valign=bottom> <br> |
| <font color="#000000" face="helvetica, arial"><a name="AllOrNothing">class <strong>AllOrNothing</strong></a></font></td></tr> |
| |
| <tr bgcolor="#ffc8d8"><td rowspan=2><tt> </tt></td> |
| <td colspan=2><tt>Class implementing the All-or-Nothing package transform.<br> |
| <br> |
| Methods for subclassing:<br> |
| <br> |
| _inventkey(key_size):<br> |
| Returns a randomly generated key. Subclasses can use this to<br> |
| implement better random key generating algorithms. The default<br> |
| algorithm is probably not very cryptographically secure.<br> </tt></td></tr> |
| <tr><td> </td> |
| <td width="100%">Methods defined here:<br> |
| <dl><dt><a name="AllOrNothing-__init__"><strong>__init__</strong></a>(self, ciphermodule, mode<font color="#909090">=None</font>, IV<font color="#909090">=None</font>)</dt><dd><tt><a href="#AllOrNothing">AllOrNothing</a>(ciphermodule, mode=None, IV=None)<br> |
| <br> |
| ciphermodule is a module implementing the cipher algorithm to<br> |
| use. It must provide the <a href="http://www.python.org/dev/peps/pep-0272/">PEP272</a> interface.<br> |
| <br> |
| Note that the encryption key is randomly generated<br> |
| automatically when needed. Optional arguments mode and IV are<br> |
| passed directly through to the ciphermodule.new() method; they<br> |
| are the feedback mode and initialization vector to use. All<br> |
| three arguments must be the same for the object used to create<br> |
| the digest, and to undigest'ify the message blocks.</tt></dd></dl> |
| |
| <dl><dt><a name="AllOrNothing-digest"><strong>digest</strong></a>(self, text)</dt><dd><tt><a href="#AllOrNothing-digest">digest</a>(text:string) : [string]<br> |
| <br> |
| Perform the All-or-Nothing package transform on the given<br> |
| string. Output is a list of message blocks describing the<br> |
| transformed text, where each block is a string of bit length equal<br> |
| to the ciphermodule's block_size.</tt></dd></dl> |
| |
| <dl><dt><a name="AllOrNothing-undigest"><strong>undigest</strong></a>(self, blocks)</dt><dd><tt><a href="#AllOrNothing-undigest">undigest</a>(blocks : [string]) : string<br> |
| <br> |
| Perform the reverse package transformation on a list of message<br> |
| blocks. Note that the ciphermodule used for both transformations<br> |
| must be the same. blocks is a list of strings of bit length<br> |
| equal to the ciphermodule's block_size.</tt></dd></dl> |
| |
| </td></tr></table></td></tr></table><p> |
| <table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section"> |
| <tr bgcolor="#55aa55"> |
| <td colspan=3 valign=bottom> <br> |
| <font color="#ffffff" face="helvetica, arial"><big><strong>Data</strong></big></font></td></tr> |
| |
| <tr><td bgcolor="#55aa55"><tt> </tt></td><td> </td> |
| <td width="100%"><strong>__revision__</strong> = '$Id: AllOrNothing.py,v 1.8 2003/02/28 15:23:20 akuchling Exp $'</td></tr></table> |
| </body></html> |
