What is XML Digital Signature?

[This feature was first implemented for MSXML 5.0.]

In a paper document, a signature ensures the integrity of the document and the authenticity of the author or signer. This is because a signature is unique to the signer. In essence, signature serves to ensure data integrity, authenticity, and non-repudiation in the process of data exchange.

Similarly, digital signature ensures authenticity, integrity, and non-repudiation for an electronic document. Digital signature relies on the public key infrastructure (PKI), in which an electronic document is uniquely bound to the signer by means of the encryption and decryption of a thumbprint (digest or hash) of the document. This encryption and decryption is accomplished using a pair of public and private keys.

XML Digital Signature is an XML representation of digital signature applied over arbitrary documents. The syntax and semantics of XML digital signature follows the W3C standard as specified in "XML-Signature Syntax and Processing, W3C Recommendation 12 February 2002".

This section contains the following topics.

• Public and Private Key Pairs
• Certificates and Certificate Authority
• Encryption and Decryption
• Digest or Hash
• Digital Signature
• XML Digital Signature
• CAPICOM and CryptoAPI