<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Verifying a signed document: XML Security Library Reference Manual</title> <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> <link rel="home" href="index.html" title="XML Security Library Reference Manual"> <link rel="up" href="xmlsec-notes-verify-decrypt.html" title="Verifing and decrypting documents."> <link rel="prev" href="xmlsec-notes-verify-decrypt.html" title="Verifing and decrypting documents."> <link rel="next" href="xmlsec-notes-decrypt.html" title="Decrypting an encrypted document"> <meta name="generator" content="GTK-Doc V1.25 (XML mode)"> <link rel="stylesheet" href="style.css" type="text/css"> <style type="text/css"> table.CALSTABLE > tbody > tr:nth-child(1) > td:nth-child(1) { width: 20em; } .synopsis, .classsynopsis { background: #eeeeee; border: solid 1px #aaaaaa; } .programlisting { background: #eeeeee; border: solid 1px #000000; } .navigation { background: #eeeeee; 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"> <li class="listitem"><p> Load keys, X509 certificates, etc. in the <a class="link" href="xmlsec-keysmngr.html#xmlSecKeysMngr" title="struct xmlSecKeysMngr">keys manager</a> . </p></li> <li class="listitem"><p> Create signature context <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtx" title="struct xmlSecDSigCtx">xmlSecDSigCtx</a> using <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtxCreate" title="xmlSecDSigCtxCreate ()">xmlSecDSigCtxCreate</a> or <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtxInitialize" title="xmlSecDSigCtxInitialize ()">xmlSecDSigCtxInitialize</a> functions. </p></li> <li class="listitem"><p> Select start verification <a class="ulink" href="" target="_top"><dsig:Signature/></a> node in the signed XML document. </p></li> <li class="listitem"><p> Verify signature by calling <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtxVerify" title="xmlSecDSigCtxVerify ()">xmlSecDSigCtxVerify</a> function. </p></li> <li class="listitem"><p> Check returned value and verification status (<em class="structfield"><code>status</code></em> member of <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtx" title="struct xmlSecDSigCtx">xmlSecDSigCtx</a> structure). If necessary, consume returned data from the <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtx" title="struct xmlSecDSigCtx">context</a>. </p></li> <li class="listitem"><p> Destroy signature context <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtx" title="struct xmlSecDSigCtx">xmlSecDSigCtx</a> using <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtxDestroy" title="xmlSecDSigCtxDestroy ()">xmlSecDSigCtxDestroy</a> or <a class="link" href="xmlsec-xmldsig.html#xmlSecDSigCtxFinalize" title="xmlSecDSigCtxFinalize ()">xmlSecDSigCtxFinalize</a> functions. </p></li> </ul></div> <p> </p> <p> </p> <div class="example"> <a name="id-1.2.8.3.3.1"></a><p class="title"><b>Example 14. Verifying a document.</b></p> <div class="example-contents"> <pre class="programlisting"> /** * verify_file: * @xml_file: the signed XML file name. * @key_file: the PEM public key file name. * * Verifies XML signature in #xml_file using public key from #key_file. * * Returns 0 on success or a negative value if an error occurs. */ int verify_file(const char* xml_file, const char* key_file) { xmlDocPtr doc = NULL; xmlNodePtr node = NULL; xmlSecDSigCtxPtr dsigCtx = NULL; int res = -1; assert(xml_file); assert(key_file); /* load file */ doc = xmlParseFile(xml_file); if ((doc == NULL) || (xmlDocGetRootElement(doc) == NULL)){ fprintf(stderr, "Error: unable to parse file \"%s\"\n", xml_file); goto done; } /* find start node */ node = xmlSecFindNode(xmlDocGetRootElement(doc), xmlSecNodeSignature, xmlSecDSigNs); if(node == NULL) { fprintf(stderr, "Error: start node not found in \"%s\"\n", xml_file); goto done; } /* create signature context, we don't need keys manager in this example */ dsigCtx = xmlSecDSigCtxCreate(NULL); if(dsigCtx == NULL) { fprintf(stderr,"Error: failed to create signature context\n"); goto done; } /* load public key */ dsigCtx->signKey = xmlSecCryptoAppKeyLoad(key_file,xmlSecKeyDataFormatPem, NULL, NULL, NULL); if(dsigCtx->signKey == NULL) { fprintf(stderr,"Error: failed to load public pem key from \"%s\"\n", key_file); goto done; } /* set key name to the file name, this is just an example! */ if(xmlSecKeySetName(dsigCtx->signKey, key_file) < 0) { fprintf(stderr,"Error: failed to set key name for key from \"%s\"\n", key_file); goto done; } /* Verify signature */ if(xmlSecDSigCtxVerify(dsigCtx, node) < 0) { fprintf(stderr,"Error: signature verify\n"); goto done; } /* print verification result to stdout */ if(dsigCtx->status == xmlSecDSigStatusSucceeded) { fprintf(stdout, "Signature is OK\n"); } else { fprintf(stdout, "Signature is INVALID\n"); } /* success */ res = 0; done: /* cleanup */ if(dsigCtx != NULL) { xmlSecDSigCtxDestroy(dsigCtx); } if(doc != NULL) { xmlFreeDoc(doc); } return(res); } </pre> <p><a class="link" href="xmlsec-verify-with-key.html#xmlsec-example-verify1" title="verify1.c">Full Program Listing</a></p> </div> </div> <p><br class="example-break"> </p> </div> <div class="footer"> <hr>Generated by GTK-Doc V1.25</div> </td></tr></table></td> </tr></table></body> </html>