132 lines
7.7 KiB
HTML
132 lines
7.7 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Supported SSL and Transport Layer Security (TLS) protocols" />
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<meta name="abstract" content="This topic describes which versions off the SSL and TLS protocols the i5/OS implementation supports." />
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<meta name="description" content="This topic describes which versions off the SSL and TLS protocols the i5/OS implementation supports." />
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<meta name="DC.Relation" scheme="URI" content="http://www.rfc-editor.org/rfcsearch.html" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2002, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2002, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="rzaintls" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Supported SSL and Transport Layer Security (TLS) protocols</title>
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</head>
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<body id="rzaintls"><a name="rzaintls"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Supported SSL and Transport Layer Security (TLS) protocols</h1>
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<div><p>This topic describes which versions off the SSL and TLS protocols
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the i5/OS™ implementation
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supports.</p>
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<div class="p">There are several versions of the SSL protocol defined. The latest version,
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the Transport Layer Security Protocol (TLS), is based on SSL 3.0 and is a
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product of the Internet Engineering Task Force (IETF). The i5/OS implementation
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supports the following versions of the SSL and TLS protocols: <ul><li>TLS Version 1.0</li>
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<li>TLS Version 1.0 with SSL Version 3.0 compatibility <div class="note"><span class="notetitle">Note:</span> <ol><li>Specifying TLS Version 1.0 with SSL Version 3.0 compatibility means that
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TLS will be negotiated if possible and if that is not possible then SSL Version
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3.0 will be negotiated. If SSL Version 3.0 cannot be negotiated, the SSL
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handshake will fail.</li>
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<li>The iSeries system also supports TLS Version 1.0 with SSL Version 3.0 and SSL Version 2.0
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compatibility. This is specified with the protocol value of <strong>ALL</strong>,
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which means that TLS will be negotiated if possible and if that is not possible
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then SSL Version 3.0 will be negotiated. If SSL Version 3.0 cannot be negotiated,
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SSL Version 2.0 will be negotiated. If SSL Version 2.0 cannot be negotiated,
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the SSL handshake will fail.</li>
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</ol>
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</div>
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</li>
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<li>SSL Version 3.0</li>
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<li>SSL Version 2.0</li>
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<li>SSL Version 3.0 with SSL Version 2.0 compatibility</li>
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</ul>
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</div>
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<div class="section"><h4 class="sectiontitle">SSL Version 3.0 versus SSL Version 2.0</h4><div class="p"> SSL version
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3.0 is an almost totally different protocol compared to SSL Version 2.0.
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Some of the major differences between the two protocols include: <ul><li>SSL Version 3.0 handshake protocol flows are different than SSL Version
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2.0 handshake flows.</li>
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<li>SSL Version 3.0 uses the BSAFE 3.0 implementation from RSA Data Security,
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Incorporated. BSAFE 3.0 includes a number of timing attack fixes and the
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SHA-1 hashing algorithm. The SHA-1 hashing algorithm is considered to be
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more secure than the MD5 hashing algorithm. SHA-1 allows SSL Version 3.0
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to support additional cipher suites which use SHA-1 instead of MD5. </li>
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<li>SSL Version 3.0 protocol reduces man-in-the-middle (MITM) type of attacks
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from occurring during SSL handshake processing. In SSL Version 2.0, it was
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possible, though unlikely, that a MITM attack might accomplish cipher specification
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weakening. Weakening the cipher can allow an unauthorized person to break
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the SSL session key.</li>
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</ul>
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</div>
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</div>
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<div class="section"><h4 class="sectiontitle">TLS Version 1.0 versus SSL Version 3.0</h4><p>The latest
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industry standard SSL protocol based on SSL version 3.0 is Transport Layer
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Security (TLS) Version 1.0. Its specifications are defined by the Internet
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Engineering Task Force (IETF) in RFC 2246, <cite>The TLS Protocol.</cite>.</p>
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<div class="p"> The
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major goal of TLS is to make SSL more secure and to make the specification
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of the protocol more precise and complete. TLS provides these enhancements
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over SSL Version 3.0: <ul><li>A more secure MAC algorithm</li>
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<li>More granular alerts</li>
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<li>Clearer definitions of "gray area" specifications</li>
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</ul>
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</div>
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<p>Any iSeries™ server
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applications that are enabled for SSL will automatically obtain TLS support
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unless the application has specifically requested to use only SSL Version
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3.0 or SSL Version 2.0. </p>
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<div class="p">TLS provides the following security improvements: <ul><li><strong>Key-Hashing for Message Authentication</strong>TLS uses Key-Hashing for
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Message Authentication Code (HMAC), which ensures that a record cannot be
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altered while travelling over an open network such as the Internet. SSL Version
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3.0 also provides keyed message authentication, but HMAC is more secure than
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the (Message Authentication Code) MAC function that SSL Version 3.0 uses.
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<p></p>
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</li>
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<li><strong>Enhanced Pseudorandom Function (PRF)</strong> PRF generates key data. In
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TLS, the HMAC defines the PRF. The PRF uses two hash algorithms in a way which
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guarantees its security. If either algorithm is exposed, the data will remain
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secure as long as the second algorithm is not exposed. <p></p>
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</li>
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<li><strong>Improved finished message verification</strong>Both TLS Version 1.0 and
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SSL Version 3.0 provide a finished message to both endpoints that authenticates
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that the exchanged messages were not altered. However, TLS bases this finished
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message on the PRF and HMAC values, which again is more secure than SSL Version
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3.0. <p></p>
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</li>
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<li><strong>Consistent certificate handling</strong>Unlike SSL Version 3.0, TLS attempts
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to specify the type of certificate which must be exchanged between TLS implementations. <p></p>
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</li>
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<li><strong>Specific alert messages</strong>TLS provides more specific and additional
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alerts to indicate problems that either session endpoint detects. TLS also
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documents when certain alerts should be sent. <p></p>
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</li>
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</ul>
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</div>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzainconcepts.htm" title="SSL concepts includes supplemental information, providing some basic building blocks for the Secure Sockets Layer (SSL) protocols.">Concepts</a></div>
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</div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
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<div><a href="rzainhistory.htm" title="Netscape developed The Secure Sockets Layer Protocol (SSL) in 1994, as a response to the growing concern over security on the Internet.">History of SSL</a></div>
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</div>
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<div class="relinfo"><strong>Related information</strong><br />
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<div><a href="http://www.rfc-editor.org/rfcsearch.html" target="_blank">The TLS Protocol</a></div>
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</div>
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</div>
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</body>
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</html>
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