106 lines
7.0 KiB
HTML
106 lines
7.0 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 name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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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="Digital signatures" />
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<meta name="abstract" content="Learn about what digital signatures are and what protection they provide." />
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<meta name="description" content="Learn about what digital signatures are and what protection they provide." />
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<meta name="DC.Relation" scheme="URI" content="rzalzobjconcepts.htm" />
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<meta name="DC.Relation" scheme="URI" content="../rzahu/rzahurazhudigitalcertmngmnt.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzalzsignableobjects.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2004, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2004, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="digitalsignatures" />
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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>Digital signatures</title>
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</head>
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<body id="digitalsignatures"><a name="digitalsignatures"><!-- --></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">Digital signatures</h1>
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<div><p>Learn about what digital signatures are and what protection they
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provide.</p>
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<p>i5/OS™ provides
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support for using digital certificates to digitally "sign" objects. A digital
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signature on an object is created by using a form of cryptography and is like
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a personal signature on a written document. A digital signature provides proof
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of the object's origin and a means by which to verify the object's integrity.
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A digital certificate owner "signs" an object by using the certificate's private
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key. The recipient of the object uses the certificate's corresponding public
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key to decrypt the signature, which verifies the integrity of the signed object
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and verifies the sender as the source.</p>
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<p> Object signing support augments traditional iSeries™ server tools for controlling
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who can change objects. Traditional controls cannot protect an object from
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unauthorized tampering while the object is in transit across the Internet
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or other untrusted network. Because you can detect whether the contents of
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an object have been changed since they were signed, you can more easily determine
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whether to trust objects that you obtain in cases such as these. </p>
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<p>A digital signature is an encrypted mathematical summary of the data in
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an object. The object and its contents are not encrypted and made private
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by the digital signature; however, the summary itself is encrypted to prevent
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unauthorized changes to it. Anyone who wants to ensure that the object has
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not been changed in transit and that the object originated from an accepted,
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legitimate source can use the signing certificate's public key to verify the
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original digital signature. If the signature no longer matches, the data may
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have been altered. In such a case, the recipient can avoid using the object
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and can instead contact the signer to obtain another copy of the signed object.</p>
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<p>The signature on an object represents the system that signed the object,
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not a specific user on that system (although the user must have the appropriate
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authority to use the certificate for signing objects). </p>
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<p>If you decide that using digital signatures fits your security needs and
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policies, you need to evaluate whether to use <a href="../rzahu/rzahurzahu4afinternetvsprivcert.htm">public certificates versus issuing local certificates</a>.
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If you intend to distribute objects to users in the general public, you need
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to consider using certificates from a well-known public Certificate Authority
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(CA) to sign objects. Using public certificates ensures that others can easily
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and inexpensively verify the signatures that you place on objects that you
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distribute to them. If, however, you intend to distribute objects solely within
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your organization, you may prefer to use <a href="../rzahu/rzahurazhudigitalcertmngmnt.htm">Digital Certificate Manager</a> (DCM) to operate your own
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Local CA to issue certificates for signing objects. Using private certificates
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from a Local CA to sign objects is less expensive than purchasing certificates
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from a well-known public CA.</p>
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<div class="section"><h4 class="sectiontitle">Types of digital signatures</h4><p>Beginning in V5R2, you
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can sign command (*CMD) objects; you also can choose one of two types of signatures
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for *CMD objects: core object signatures or entire object signatures. </p>
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<ul><li><strong>Entire object signatures</strong> This type of signature includes all but
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a few nonessential bytes of the object. </li>
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<li><strong>Core object signatures</strong> This type of signature includes the essential
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bytes of the *CMD object. However, the signature does not include those bytes
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that are subject to more frequent changes. This type of signature allows some
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changes to be made to the command without invalidating the signature. Which
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bytes the core object signature does not include vary based on the specific
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*CMD object; core signatures do not include parameter defaults on the *CMD
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objects, for example. Examples of changes that will not invalidate a core
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object signature include: <ul><li>Changing command defaults.</li>
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<li>Adding a validity checking program to a command that does not have one.</li>
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<li>Changing the Where allowed to run parameter. </li>
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<li>Changing the Allow limited users parameter. </li>
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</ul>
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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 class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzalzobjconcepts.htm" title="Use this concept and reference information to learn more about digital signatures and the object signing and signature verification processes work.">Object signing 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="rzalzsignableobjects.htm" title="Learn about which objects you can sign and about command (*CMD) object signature options.">Signable objects</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="../rzahu/rzahurazhudigitalcertmngmnt.htm">Digital Certificate Manager (DCM)</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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