XMLsignaturer

XMLsignaturer is a term that generally refers to tools, libraries, or implementations that create, verify, and manage XML Digital Signatures (XML‑DSig), a standard defined by the World Wide Web Consortium (W3C) for signing XML data. The XML Signature framework enables the authentication of the origin of an XML document, ensures data integrity, and, when combined with encryption, can provide non‑repudiation.

The core of an XML digital signature consists of a <Signature> element that contains one or more signed <Reference> elements, each identifying a portion of the XML to be signed, a digest value computed with a hash algorithm (e.g., SHA‑256), and a signature value generated with a private key using a public‑key algorithm such as RSA or ECDSA. A <KeyInfo> sub‑element may embed or reference the signer's public key or certificate, allowing recipients to verify the signature without prior key exchange.

Implementations referred to as XMLsignaturer typically provide an API for developers to:

1. Canonicalize XML fragments to a deterministic byte representation (C14N), mitigating variations in whitespace or attribute ordering.

2. Compute digests and generate signature values in compliance with the XML‑DSig schema.

3. Attach or detach the <Signature> element within the original document or as an enveloped, enveloping, or detached signature.

4. Validate existing signatures, checking references, digest consistency, and certificate trust chains.

Common programming languages offer such capabilities through libraries like Apache Santuario (Java), .NET System.Security.Cryptography.Xml, and XMLSec (C). These libraries handle the complex steps of canonicalization, namespace management, and policy enforcement, allowing applications ranging from web services and SOAP messaging to electronic invoicing and e‑government data exchange to secure XML payloads. Proper use of XMLsignaturer components contributes to interoperable, standards‑based security across heterogeneous systems.