Otherwise, the signature would include itself in the data to be signed, which is not correct. The enveloped transform is required for enveloped signatures so that the Signature element itself is removed before calculating the signature value. This example contains one Transform element for the enveloped transform algorithm. The optional Transforms element contains a list of one or more Transform elements, each of which describes a transformation algorithm used to transform the data before it is digested and signed, or validated. The Reference URIs could also point to external data, such as " or to references within the same document, such as "#purchaseOrder".
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The example in XML Sample 3 contains a single Reference element, and the URI is the empty String, "", which indicates the root of the document - in other words, the whole document. Each Reference element identifies the data by way of a URI. One or more Reference elements identify the data that is signed. The SignatureMethod element defines as a URI the digital signature algorithm used to generate the signature, in this case the PKCS#1 RSA-SHA1 algorithm as described in RFC 2437.
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Canonicalization eliminates these permissible syntactic variances by converting the XML to a canonical form before generating or validating the signature. Canonicalization is necessary due to the nature of XML and the way it is parsed by different processors and intermediaries, which can change the data in such a way that the signature is no longer valid but the signed data is still logically equivalent. Canonicalization is the process of converting XML content to a physical representation, called the canonical form, in order to eliminate subtle changes that can invalidate a signature over that data. The CanonicalizationMethod element defines as a URI the algorithm used to canonicalize the SignedInfo element before it is signed or validated. XML Sample 3 shows the SignedInfo element that contains the information that is actually signed XML Sample 3 Note that the Signature element has been inserted inside the content that it is signing, thereby making it an enveloped signature. MA4GA1UEAxMHTXkgTmFtZTAeFw0wNzAxMDMyMTE4MTFaFw0zMTA4MjUy VQQGEwJVUzEfMB0GA1UEChMWVGVzdCBDZXJ0aWZpY2F0ZXMgSW5jLjEQ MIIB9zCCAWCgAwIBAgIERZwdkzANBgkqhkiG9w0BAQUFADBAMQswCQYD XML Sample 1ĭJDHiGQMaKN8iPuWApAL57eVnxz2BQtyujwfPSgE7HyKoxYtoRB97ocxZĨZU440wHtE39ZwRGIjvwor3WfURxnIgnI1CChMXXwoGpHH//Zc0z4ejazĭuCNEq4Mm4OUVTiEVuwcWAOMkfDHaM82awYQiOGcwMbZe38UX0oPJ2DOE= XML Sample 1 shows the contents of the purchase order before it is signed. The article will also use this sample in the subsequent sections on using the API. The example that this article will use is an enveloped XML signature generated over the contents of an XML document, a sample purchase order. Perhaps the best way to describe an XML signature is to step through the contents of an example in detail.
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#JAVA FOR DIGITAL SIGNATURE FREE HOW TO#
This article will give you an overview of XML signatures and show you how to use the API in your applications. XML signatures are a standard for digital signatures in the XML data format, and they allow you to authenticate and protect the integrity of data in XML and web service transactions. This API allows you to generate and validate XML signatures. One of the significant new features of the Java Platform, Standard Edition 6 (Java SE 6) is the Java XML Digital Signature API.