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diff --git a/api/2.0.1/node5.html b/api/2.0.1/node5.html new file mode 100644 index 0000000..2fdc9eb --- /dev/null +++ b/api/2.0.1/node5.html @@ -0,0 +1,178 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> + +<!--Converted with LaTeX2HTML 2008 (1.71) +original version by: Nikos Drakos, CBLU, University of Leeds +* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan +* with significant contributions from: + Jens Lippmann, Marek Rouchal, Martin Wilck and others --> +<HTML> +<HEAD> +<TITLE>Crypto.Hash: Hash Functions</TITLE> +<META NAME="description" CONTENT="Crypto.Hash: Hash Functions"> +<META NAME="keywords" CONTENT="pycrypt"> +<META NAME="resource-type" CONTENT="document"> +<META NAME="distribution" CONTENT="global"> + +<META NAME="Generator" CONTENT="LaTeX2HTML v2008"> +<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css"> + +<LINK REL="STYLESHEET" HREF="pycrypt.css"> + +<LINK REL="next" HREF="node8.html"> +<LINK REL="previous" HREF="node2.html"> +<LINK REL="up" HREF="pycrypt.html"> +<LINK REL="next" HREF="node6.html"> +</HEAD> + +<BODY > + +<DIV CLASS="navigation"><!--Navigation Panel--> +<A NAME="tex2html116" + HREF="node6.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> +<A NAME="tex2html112" + HREF="pycrypt.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> +<A NAME="tex2html106" + HREF="node4.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> +<A NAME="tex2html114" + HREF="node1.html"> +<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> +<BR> +<B> Next:</B> <A NAME="tex2html117" + HREF="node6.html">Security Notes</A> +<B> Up:</B> <A NAME="tex2html113" + HREF="pycrypt.html">Python Cryptography Toolkit</A> +<B> Previous:</B> <A NAME="tex2html107" + HREF="node4.html">Acknowledgements</A> + <B> <A NAME="tex2html115" + HREF="node1.html">Contents</A></B> +<BR> +<BR></DIV> +<!--End of Navigation Panel--> + +<H1><A NAME="SECTION00030000000000000000"> +Crypto.Hash: Hash Functions</A> +</H1> + +<P> +Hash functions take arbitrary strings as input, and produce an output +of fixed size that is dependent on the input; it should never be +possible to derive the input data given only the hash function's +output. One simple hash function consists of simply adding together +all the bytes of the input, and taking the result modulo 256. For a +hash function to be cryptographically secure, it must be very +difficult to find two messages with the same hash value, or to find a +message with a given hash value. The simple additive hash function +fails this criterion miserably and the hash functions described below +meet this criterion (as far as we know). Examples of +cryptographically secure hash functions include MD2, MD5, and SHA1. + +<P> +Hash functions can be used simply as a checksum, or, in association with a +public-key algorithm, can be used to implement digital signatures. + +<P> +The hashing algorithms currently implemented are: + +<P> +<BR> +1#1 +<BR> + +<P> +All hashing modules share the same interface. After importing a given +hashing module, call the new() function to create a new +hashing object. You can now feed arbitrary strings into the object +with the update() method, and can ask for the hash value at +any time by calling the digest() or hexdigest() +methods. The new() function can also be passed an optional +string parameter that will be immediately hashed into the object's +state. + +<P> +Hash function modules define one variable: + +<P> +<BR> +2#2 +<BR> + +<P> +The methods for hashing objects are always the following: + +<P> +<BR> +3#3 +<BR> + +<P> +<BR> +4#4 +<BR> + +<P> +<BR> +5#5 +<BR> + +<P> +<BR> +6#6 +<BR> + +<P> +Here's an example, using the MD5 algorithm: + +<P> +<PRE> +>>> from Crypto.Hash import MD5 +>>> m = MD5.new() +>>> m.update('abc') +>>> m.digest() +'\x90\x01P\x98<\xd2O\xb0\xd6\x96?}(\xe1\x7fr' +>>> m.hexdigest() +'900150983cd24fb0d6963f7d28e17f72' +</PRE> + +<P> +<BR><HR> +<!--Table of Child-Links--> +<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A> + +<UL CLASS="ChildLinks"> +<LI><A NAME="tex2html118" + HREF="node6.html">Security Notes</A> +<LI><A NAME="tex2html119" + HREF="node7.html">Credits</A> +</UL> +<!--End of Table of Child-Links--> + +<DIV CLASS="navigation"><HR> +<!--Navigation Panel--> +<A NAME="tex2html116" + HREF="node6.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> +<A NAME="tex2html112" + HREF="pycrypt.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> +<A NAME="tex2html106" + HREF="node4.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> +<A NAME="tex2html114" + HREF="node1.html"> +<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> +<BR> +<B> Next:</B> <A NAME="tex2html117" + HREF="node6.html">Security Notes</A> +<B> Up:</B> <A NAME="tex2html113" + HREF="pycrypt.html">Python Cryptography Toolkit</A> +<B> Previous:</B> <A NAME="tex2html107" + HREF="node4.html">Acknowledgements</A> + <B> <A NAME="tex2html115" + HREF="node1.html">Contents</A></B> </DIV> +<!--End of Navigation Panel--> + +</BODY> +</HTML> |