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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Frameset//EN""http://www.w3.org/TR/REC-html40/frameset.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc on Thu Apr 27 23:35:58 PDT 2000 --><TITLE>Java 2 Platform SE v1.3: Class KeyFactory</TITLE><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"></HEAD><BODY BGCOLOR="white"><!-- ========== START OF NAVBAR ========== --><A NAME="navbar_top"><!-- --></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0"><TR><TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3"> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="class-use/KeyFactory.html"><FONT CLASS="NavBarFont1"><B>Use</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-files/index-1.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM><b>Java<sup><font size=-2>TM</font></sup> 2 Platform<br>Std. Ed. v1.3</b></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../java/security/IdentityScope.html"><B>PREV CLASS</B></A> <A HREF="../../java/security/KeyFactorySpi.html"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html" TARGET="_top"><B>FRAMES</B></A> <A HREF="KeyFactory.html" TARGET="_top"><B>NO FRAMES</B></A></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: INNER | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><!-- =========== END OF NAVBAR =========== --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">java.security</FONT><BR>Class KeyFactory</H2><PRE><A HREF="../../java/lang/Object.html">java.lang.Object</A> | +--<B>java.security.KeyFactory</B></PRE><HR><DL><DT>public class <B>KeyFactory</B><DT>extends <A HREF="../../java/lang/Object.html">Object</A></DL><P>Key factories are used to convert <I>keys</I> (opaque cryptographic keys of type <code>Key</code>) into <I>key specifications</I> (transparent representations of the underlying key material), and vice versa. <P> Key factories are bi-directional. That is, they allow you to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format. <P> Multiple compatible key specifications may exist for the same key. For example, a DSA public key may be specified using <code>DSAPublicKeySpec</code> or <code>X509EncodedKeySpec</code>. A key factory can be used to translate between compatible key specifications. <P> The following is an example of how to use a key factory in order to instantiate a DSA public key from its encoding. Assume Alice has received a digital signature from Bob. Bob also sent her his public key (in encoded format) to verify his signature. Alice then performs the following actions: <pre> X509EncodedKeySpec bobPubKeySpec = new X509EncodedKeySpec(bobEncodedPubKey); KeyFactory keyFactory = KeyFactory.getInstance("DSA"); PublicKey bobPubKey = keyFactory.generatePublic(bobPubKeySpec); Signature sig = Signature.getInstance("DSA"); sig.initVerify(bobPubKey); sig.update(data); sig.verify(signature); </pre><P><DL><DT><B>Since: </B><DD>1.2</DD><DT><B>See Also: </B><DD><A HREF="../../java/security/Key.html"><CODE>Key</CODE></A>, <A HREF="../../java/security/PublicKey.html"><CODE>PublicKey</CODE></A>, <A HREF="../../java/security/PrivateKey.html"><CODE>PrivateKey</CODE></A>, <A HREF="../../java/security/spec/KeySpec.html"><CODE>KeySpec</CODE></A>, <A HREF="../../java/security/spec/DSAPublicKeySpec.html"><CODE>DSAPublicKeySpec</CODE></A>, <A HREF="../../java/security/spec/X509EncodedKeySpec.html"><CODE>X509EncodedKeySpec</CODE></A></DL><HR><P><!-- ======== INNER CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected </CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#KeyFactory(java.security.KeyFactorySpi, java.security.Provider, java.lang.String)">KeyFactory</A></B>(<A HREF="../../java/security/KeyFactorySpi.html">KeyFactorySpi</A> keyFacSpi, <A HREF="../../java/security/Provider.html">Provider</A> provider, <A HREF="../../java/lang/String.html">String</A> algorithm)</CODE><BR> Creates a KeyFactory object.</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/security/PrivateKey.html">PrivateKey</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#generatePrivate(java.security.spec.KeySpec)">generatePrivate</A></B>(<A HREF="../../java/security/spec/KeySpec.html">KeySpec</A> keySpec)</CODE><BR> Generates a private key object from the provided key specification (key material).</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/security/PublicKey.html">PublicKey</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#generatePublic(java.security.spec.KeySpec)">generatePublic</A></B>(<A HREF="../../java/security/spec/KeySpec.html">KeySpec</A> keySpec)</CODE><BR> Generates a public key object from the provided key specification (key material).</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/lang/String.html">String</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#getAlgorithm()">getAlgorithm</A></B>()</CODE><BR> Gets the name of the algorithm associated with this <tt>KeyFactory</tt>.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static <A HREF="../../java/security/KeyFactory.html">KeyFactory</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#getInstance(java.lang.String)">getInstance</A></B>(<A HREF="../../java/lang/String.html">String</A> algorithm)</CODE><BR> Generates a KeyFactory object that implements the specified digest algorithm.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static <A HREF="../../java/security/KeyFactory.html">KeyFactory</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#getInstance(java.lang.String, java.lang.String)">getInstance</A></B>(<A HREF="../../java/lang/String.html">String</A> algorithm, <A HREF="../../java/lang/String.html">String</A> provider)</CODE><BR> Generates a KeyFactory object for the specified algorithm from the specified provider.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/security/spec/KeySpec.html">KeySpec</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#getKeySpec(java.security.Key, java.lang.Class)">getKeySpec</A></B>(<A HREF="../../java/security/Key.html">Key</A> key, <A HREF="../../java/lang/Class.html">Class</A> keySpec)</CODE><BR> Returns a specification (key material) of the given key object.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/security/Provider.html">Provider</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#getProvider()">getProvider</A></B>()</CODE><BR> Returns the provider of this key factory object.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/security/Key.html">Key</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/KeyFactory.html#translateKey(java.security.Key)">translateKey</A></B>(<A HREF="../../java/security/Key.html">Key</A> key)</CODE><BR> Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.</TD></TR></TABLE> <A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"><TD><B>Methods inherited from 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