XML цифрлық қолтаңбаларының синтаксисі мен өңделуі

XML syntax for digital signatures
XML Signature (also called XMLDSig, XML DSig, XML Sig) defines an XML syntax for digital signatures and is defined in the W3C recommendation XML Signature Syntax and Processing. Functionally, it has much in common with PKCS #7 but is more extensible and geared towards signing XML documents. It is used by various Web technologies such as SOAP, SAML, and others. XML signatures can be used to sign data–a resource–of any type, typically XML documents, but anything that is accessible via a URL can be signed. An XML signature used to sign a resource outside its containing XML document is called a detached signature; if it is used to sign some part of its containing document, it is called an enveloped signature; if it contains the signed data within itself it is called an enveloping signature.

When validating an XML Signature, a procedure called Core Validation is followed. Reference Validation: Each Reference's digest is verified by retrieving the corresponding resource and applying any transforms and then the specified digest method to it. The result is compared to the recorded DigestValue; if they do not match, validation fails. Signature Validation: The SignedInfo element is serialized using the canonicalization method specified in CanonicalizationMethod, the key data is retrieved using KeyInfo or by other means, and the signature is verified using the method specified in SignatureMethod. This procedure establishes whether the resources were really signed by the alleged party. However, because of the extensibility of the canonicalization and transform methods, the verifying party must also make sure that what was actually signed or digested is really what was present in the original data, in other words, that the algorithms used there can be trusted not to change the meaning of the signed data. Because the signed document's structure can be tampered with leading to "signature wrapping" attacks, the validation process should also cover XML document structure. Signed element and signature element should be selected using absolute XPath expression, not getElementByName methods. and at the suitability of XML canonicalization in particular as a front end to signing and encrypting XML data due to its complexity, inherent processing requirement, and poor performance characteristics. The argument is that performing XML canonicalization causes excessive latency that is simply too much to overcome for transactional, performance sensitive SOA applications. These issues are being addressed in the XML Security Working Group. Without proper policy and implementation the use of XML Dsig in SOAP and WS Security can lead to vulnerabilities, such as XML signature wrapping.