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<A NAME="MessageDigestSpi()"><!-- --></A><H3>
MessageDigestSpi</H3>
<PRE>
public <B>MessageDigestSpi</B>()</PRE>
<DL>
</DL>

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<A NAME="engineGetDigestLength()"><!-- --></A><H3>
engineGetDigestLength</H3>
<PRE>
protected int <B>engineGetDigestLength</B>()</PRE>
<DL>
<DD>Returns the digest length in bytes.

 <p>This concrete method has been added to this previously-defined
 abstract class. (For backwards compatibility, it cannot be abstract.)
 
 <p>The default behavior is to return 0.
 
 <p>This method may be overridden by a provider to return the digest
 length.<DD><DL>
<DT><B>Returns:</B><DD>the digest length in bytes.<DT><B>Since: </B><DD>1.2</DD>
</DL>
</DD>
</DL>
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<A NAME="engineUpdate(byte)"><!-- --></A><H3>
engineUpdate</H3>
<PRE>
protected abstract void <B>engineUpdate</B>(byte&nbsp;input)</PRE>
<DL>
<DD>Updates the digest using the specified byte.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>input</CODE> - the byte to use for the update.</DL>
</DD>
</DL>
<HR>

<A NAME="engineUpdate(byte[], int, int)"><!-- --></A><H3>
engineUpdate</H3>
<PRE>
protected abstract void <B>engineUpdate</B>(byte[]&nbsp;input,
                                     int&nbsp;offset,
                                     int&nbsp;len)</PRE>
<DL>
<DD>Updates the digest using the specified array of bytes,    
 starting at the specified offset.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>input</CODE> - the array of bytes to use for the update.<DD><CODE>offset</CODE> - the offset to start from in the array of bytes.<DD><CODE>len</CODE> - the number of bytes to use, starting at 
 <code>offset</code>.</DL>
</DD>
</DL>
<HR>

<A NAME="engineDigest()"><!-- --></A><H3>
engineDigest</H3>
<PRE>
protected abstract byte[] <B>engineDigest</B>()</PRE>
<DL>
<DD>Completes the hash computation by performing final
 operations such as padding. Once <code>engineDigest</code> has 
 been called, the engine should be reset (see 
 <A HREF="../../java/security/MessageDigestSpi.html#engineReset()"><CODE>engineReset</CODE></A>).  
 Resetting is the responsibility of the
 engine implementor.<DD><DL>
<DT><B>Returns:</B><DD>the array of bytes for the resulting hash value.</DL>
</DD>
</DL>
<HR>

<A NAME="engineDigest(byte[], int, int)"><!-- --></A><H3>
engineDigest</H3>
<PRE>
protected int <B>engineDigest</B>(byte[]&nbsp;buf,
                           int&nbsp;offset,
                           int&nbsp;len)
                    throws <A HREF="../../java/security/DigestException.html">DigestException</A></PRE>
<DL>
<DD>Completes the hash computation by performing final
 operations such as padding. Once <code>engineDigest</code> has
 been called, the engine should be reset (see 
 <A HREF="../../java/security/MessageDigestSpi.html#engineReset()"><CODE>engineReset</CODE></A>).  
 Resetting is the responsibility of the
 engine implementor.

 This method should be abstract, but we leave it concrete for
 binary compatibility.  Knowledgeable providers should override this
 method.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>buf</CODE> - the output buffer in which to store the digest<DD><CODE>offset</CODE> - offset to start from in the output buffer<DD><CODE>len</CODE> - number of bytes within buf allotted for the digest.
 Both this default implementation and the SUN provider do not
 return partial digests.  The presence of this parameter is solely
 for consistency in our API's.  If the value of this parameter is less
 than the actual digest length, the method will throw a DigestException.
 This parameter is ignored if its value is greater than or equal to
 the actual digest length.<DT><B>Returns:</B><DD>the length of the digest stored in the output buffer.<DT><B>Throws:</B><DD><CODE><A HREF="../../java/security/DigestException.html">DigestException</A></CODE> - if an error occurs.<DT><B>Since: </B><DD>1.2</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="engineReset()"><!-- --></A><H3>
engineReset</H3>
<PRE>
protected abstract void <B>engineReset</B>()</PRE>
<DL>
<DD>Resets the digest for further use.</DL>
<HR>

<A NAME="clone()"><!-- --></A><H3>
clone</H3>
<PRE>
public <A HREF="../../java/lang/Object.html">Object</A> <B>clone</B>()
             throws <A HREF="../../java/lang/CloneNotSupportedException.html">CloneNotSupportedException</A></PRE>
<DL>
<DD>Returns a clone if the implementation is cloneable.<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../java/lang/Object.html#clone()">clone</A></CODE> in class <CODE><A HREF="../../java/lang/Object.html">Object</A></CODE></DL>
</DD>
<DD><DL>
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 implementation that does not support <code>Cloneable</code>.</DL>
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