XAdESSigner Component

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The XAdESSigner component creates XAdES-compliant signature files.

Syntax

nsoftware.SecureBlackbox.Xadessigner

Remarks

XAdESSigner can sign XML documents in accordance with XAdES standard. Originally developed and adopted in the European Union, XAdES has quickly become a recognized international standard for signing XML documents. XAdES provides a convenient framework for creating short-lived and long-term signatures over any kind of XML documents, and is now used by governments, healthcare providers, banks, and independent service providers all across the globe.

Standards and technologies supported

XAdESSigner offers the following signing capabilities:

• Create and upgrade XAdES signatures in accordance with the most recent XAdES specification (ETSI EN 319 132). Earlier versions are also supported.
• All profiles are supported (BES, EPES, T, C, X, XL, A, including the Extended variants).
• Timestamping using external TSAs.
• All industry-standard cryptographic algorithms (RSA, ECDSA, SHA256-512, and many others).

Configuring the signature parameters

Configuring XAdESSigner to make it produce a signature of the right type is the main task you would need to perform in your code. Normally the service or software you will be communicating your XML documents to will provide you with the list of requirements that your signatures should match.

Typically, those will dictate the following key aspects of the signatures:

• The signature Form, sometimes referred to as Level (such BES, T, XL, A, or Extended-XLong). This can be adjusted with the XAdESForm property.
• Whether the signature should be detached, enveloped, or enveloping: adjust via SignatureType property.
• When creating a timestamped signature (such as T or A), provide the address of your online TSA service via TimestampServer property.
• When creating long-term signatures that include the signing chain and validation material, tune up validation parameters via RevocationCheck, OfflineMode, and IgnoreChainValidationErrors properties.

In some circumstances you will also need to adjust the following lower-level settings:

• Choose a specific XAdES version between 1.4.1, 1.3.2, 1.2.2, and 1.1.1, and assign it to XAdESVersion property.
• Specify the needed canonicalization method using the CanonicalizationMethod property.
• Provide the hash algorithm via the HashAlgorithm property.

Signing certificates

XAdESSigner can use certificates residing on different media. Besides generic certificates stored in PFX or PEM files (A1), it can operate with non-exportable certificates residing on hardware media (A3) or in the cloud.

Non-exportable certificates can be accessed transparently via a Windows CSP or a PKCS#11 driver, if supplied by the certificate issuer. Proprietary interfaces can be plugged in with the external signing feature (see below).

You can use CertificateManager and CertificateStorage components to access the signing certificate. Assign the certificate to SigningCertificate property, and optionally provide the remainder of its chain via SigningChain property.

Note: If signing with a non-exportable key (such as residing on a hardware device or in the cloud), please make sure you keep the original CertificateStorage object open until the signing is completed. This is because the storage component provides a 'bridge' to the private key. If the storage is closed prematurely, this bridge is destroyed, and the private key can't be used.

You don't need to provide a signing certificate or chain when timestamping and upgrading signatures, since this type of operation does not involve the signing private key.

Signing the document

Now that you have set up all signature properties and attached the signing certificate, it is time to proceed to signing. You can provide the input document in one of the following forms: as a file (assign the path to InputFile property), as a stream (assign to InputStream property), or as a byte array (assign to InputBytes). Similarly, the output can be collected in one of the same forms, either by passing the destination path or stream via OutputFile and OutputStream respectively, or by reading the resulting document bytes from the OutputBytes property after the signing completes.

Having set up the input and output (unless using OutputBytes, which should be read later), call the component's Sign method. This will initiate the signing process. Depending on the settings, the signing may be as straightforward as calculating the document hash and signing it with the private key (e.g. in XAdES-BES variant), or it may involve advanced chain validation routines (XAdES-XL or -A). During the latter the component may contact a number of external revocation information sources (CRL and OCSP servers) to establish the validity of the signing certificate.

If a TSA server was provided via the TimestampServer property, the component will contact it too to timestamp the new signature.

During the signing XAdESSigner may fire events to let your code know of certain conditions. It may fire TLSCertValidate if one of the HTTP endpoints involved in the operation (which may be a CRL, OCSP, or TSA service) works over TLS and needs its certificate to be validated. It may also fire FormatElement and FormatText to let your code apply custom formatting to XML document elements. If XAdESSigner fails to resolve one of the references in the signature, it will fire ResolveReference to let your code help with resolving it.

When the signing operation completes, the output file, stream, or byte array will contain the signature of the requested kind. Note that while nveloped and enveloping signatures contain the signed content within them, detached signatures assume that you supply the original content separately.

Apart from signing, XAdESSigner can perform operations on signatures of other kinds. Use Upgrade method to upgrade an existing XAdES signature to a higher level (e.g. BES to XL). Use Timestamp to add a generic or validation timestamp to an existing signature.

External signing and DCAuth

XAdESSigner, like many other components offered by the product, supports two methods of signing with external keys. These methods are fully independent of each other: you can choose the one that suits your usage scenario best.

Synchronous method: ExternalSign

This is a simpler method that basically lets you infiltrate into the heart of the signing routine by taking care of the hash signing operation. The component does the rest of the job (hash calculation, preparation of signature objects, CRL/OCSP retrieval).

To initiate this method, call SignExternal instead of Sign. When the hash is ready, it will be passed back to your code with ExternalSign event. Your event handler needs to sign the hash with the private key and return the created signature back to the component - which will embed it into the document.

You don't need your signing certificate to contain an associated private key when using this method. The certificate itself (its public copy) may be needed though, as it is often included in the hash calculation.

This method is synchronous, meaning SignExternal provides you the results immediately upon its completion.

Asynchronous method: DCAuth

DCAuth is a SecureBlackbox-own know-how technology. This protocol was designed to allow sharing of private keys across environments, allowing the signer and the private key to reside on different systems. It works in the following way:

• The signing party - such as XAdESSigner - initiates the operation using SignAsyncBegin call. This produces two outcomes: a pre-signed document (a document with a blank signature placeholder), and a request state (an object containing a hash that needs to be signed). At this point the XAdESSigner instance can be released, and the process itself terminated (which may be useful when run as part of a web page).
• The request state is passed to the private key holder party. The private key holder passes the request state to a DCAuth object, which parses the request state, extracts the hash, and signs it. The output of DCAuth processing is another object, response state, which contains the signature. The private key holder then sends the response state back to the signing party.
• The signing party re-creates the controls, and passes the response state, together with the pre-signed version of the document, to the signer's SignAsyncEnd method. SignAsyncEnd extracts the signature from the response state and incorporates it into the pre-signed document.

This method is asynchronous in that sense that, from the signing party's viewpoint, it splits the signing operation into the pre-signing and completion stages which can be performed independently from each other and in different execution contexts. This makes this method particularly helpful for use in web pages and other scenarios where the signing key is not available in real time.

Fine-grained chain validation setup

Chain validation is a sophisticated, multi-faceted procedure that involves a lot of variables. Depending on the configuration of your operating environment, the specifics of the PKI framework being used, and the validation policy you need to follow, you may want to tune up your chain validation parameters so they fit them best. Below is given a summary of such parameters.

• RevocationCheck property lets you choose between and/or prioritize revocation origins. OCSP sources are often preferred to CRL because of their real-time capability and the smaller size of validation tokens they produce.
• OfflineMode is a master switch that stops component from looking for any validation tokens online. If this property is switched on, the component will only use KnownCertificates, TrustedCertificates, KnownCRLs, and KnownOCSPs collections to look for the missing validation material.
• IgnoreChainValidationErrors makes the component ignore any major validation issues it encounters (such us an untrusted chain or missing CRL). This option is handy for debugging and for creating signatures in the environments where the signing certificate is not trusted.
• KnownCertificates, KnownCRLs, and KnownOCSPs let you provide your own validation material. This may be useful when working in OfflineMode, where the signer has no access to the validation sources, or where the validation material has already been collected.
• TrustedCertificates lets you provide a list of trust anchors, either as a complement to the system's or as an alternative for it.
• BlockedCertificates lets you provide a list of blocked/distrusted certificates. Any CA certificate contained in it will be deemed untrusted/invalid.

The following parameters are not directly related to chain validation, but may have an implicit effect on it.

• Proxy, SocketSettings, and TLSSettings let you tune up the connectivity and TLS options in accordance with local preferences.
• TLSClientChain lets you provide the client certificate and its chain for TLS client authentication.
• Subscribe to TLSCertValidate to validate any TLS certificates of the services involved in chain validation.

The results of the chain validation procedure, upon its completion, are published in the following properties:

• ChainValidationResult contains the primary result of the chain validation routine: valid, valid but untrusted, invalid, or undefined.
• ChainValidationDetails provides the details of the factors that contributed to the chain validation result, such as an outdated certificate, a missing CRL, or a missing CA certificate.
• ValidationLog contains the detailed chain validation log. The log can often be very helpful in nailing down various validation issues.

Property List

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The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

BlockedCertificates	The certificates that must be rejected as trust anchors.
CanonicalizationMethod	Specifies XML canonicalization method to use.
ChainValidationDetails	The details of a certificate chain validation outcome.
ChainValidationResult	The general outcome of a certificate chain validation routine. Use ChainValidationDetails to get information about the reasons that contributed to the validation result.
ClaimedSigningTime	The signing time from the signer's computer.
EnableXAdES	Specifies if an advanced signature (XAdES) will be produced.
Encoding	Specifies XML encoding.
ExternalCrypto	Provides access to external signing and DC parameters.
HashAlgorithm	Specifies the hash algorithm to be used.
IgnoreChainValidationErrors	Makes the component tolerant to chain validation errors.
InputBytes	Use this property to pass the input to component in the byte array form.
InputFile	The XML document to sign.
InputStream	A stream containing the document to sign.
KnownCertificates	Additional certificates for chain validation.
KnownCRLs	Additional CRLs for chain validation.
KnownOCSPs	Additional OCSP responses for chain validation.
OfflineMode	Switches the component to the offline mode.
OutputBytes	Use this property to read the output the component object has produced.
OutputFile	Specifies the file where the signed document will be saved.
OutputStream	The stream where the signed document is saved.
Profile	Specifies a pre-defined profile to apply when creating the signature.
Proxy	The proxy server settings.
References	A list of references to the data to be signed.
RevocationCheck	Specifies the kind(s) of revocation check to perform.
SignatureType	The signature type to employ when signing the document.
SigningCertificate	The certificate to be used for signing.
SigningChain	The signing certificate chain.
SocketSettings	Manages network connection settings.
TimestampServer	The address of the timestamping server.
TLSClientChain	The TLS client certificate chain.
TLSServerChain	The TLS server's certificate chain.
TLSSettings	Manages TLS layer settings.
TrustedCertificates	A list of trusted certificates for chain validation.
ValidationLog	Contains the complete log of the certificate validation routine.
XAdESForm	Specifies which form of XAdES should be produced.
XAdESVersion	Specifies XAdES version.
XMLElement	Specifies the XML element where to save the signature data.
XPathNamespaces	Specifies namespaces for the XPath expression.

Method List

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The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

AddDataReference	Creates a new XML reference to the specified data.
AddReference	Creates a new XML reference to the specified XML element.
Config	Sets or retrieves a configuration setting.
ExtractAsyncData	Extracts user data from the DC signing service response.
Sign	Signs an XML document.
SignAsyncBegin	Initiates the asynchronous signing operation.
SignAsyncEnd	Completes the asynchronous signing operation.
SignExternal	Signs the document using an external signing facility.
Timestamp	Use this method to add timestamp.
Upgrade	Upgrades existing XAdES signature to a new form.

Event List

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The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Error	Information about errors during signing.
ExternalSign	Handles remote or external signing initiated by the SignExternal method or other source.
FormatElement	Reports the XML element that is currently being processed.
FormatText	Reports XML text that is currently being processed.
Notification	This event notifies the application about an underlying control flow event.
ResolveReference	Asks the application to resolve a reference.
StoreCertificate	This event is fired when a certificate should be stored along with a signature.
StoreCRL	This event is fired when a CRL should be stored along with a signature.
StoreOCSPResponse	This event is fired when a OCSP Response should be stored along with a signature.
TLSCertValidate	This event is fired upon receipt of the TLS server's certificate, allowing the user to control its acceptance.

Configuration Settings

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The following is a list of configuration settings for the component with short descriptions. Click on the links for further details.

ClaimedRoleText	The text of the claimed role.
ClaimedRoleXML	The XML content of the claimed roles.
CommitmentTypeIndicationAllSignedDataObjects[Index]	Specifies the CommitmentTypeIndication's AllSignedDataObjects.
CommitmentTypeIndicationCount	The number of the CommitmentTypeIndication elements.
CommitmentTypeIndicationIdentifier[Index]	Specifies the CommitmentTypeIndication's CommitmentTypeId's Identifier.
CommitmentTypeIndicationIdentifierDescription[Index]	Specifies the CommitmentTypeIndication's CommitmentTypeId's Description.
CommitmentTypeIndicationIdentifierDocumentationReferences[Index]	Specifies the CommitmentTypeIndication's CommitmentTypeId's DocumentationReferences.
CommitmentTypeIndicationIdentifierQualifier[Index]	Specifies the CommitmentTypeIndication's CommitmentTypeId's IdentifierQualifier.
CommitmentTypeIndicationObjectReference[Index]	Specifies the CommitmentTypeIndication's ObjectReference.
CommitmentTypeIndicationQualifiersXML[Index]	The XML content of the CommitmentTypeIndication's Qualifiers.
DataObjectFormatCount	The number of the DataObjectFormat elements.
DataObjectFormatDescription[Index]	Specifies the DataObjectFormat's Description.
DataObjectFormatEncoding[Index]	Specifies the DataObjectFormat's Encoding.
DataObjectFormatMimeType[Index]	Specifies the DataObjectFormat's MimeType.
DataObjectFormatObjectIdentifier[Index]	Specifies the DataObjectFormat's ObjectIdentifier's Identifier.
DataObjectFormatObjectIdentifierDescription[Index]	Specifies the DataObjectFormat's ObjectIdentifier's Description.
DataObjectFormatObjectIdentifierDocumentationReferences[Index]	Specifies the DataObjectFormat's ObjectIdentifier's DocumentationReferences.
DataObjectFormatObjectIdentifierQualifier[Index]	Specifies the DataObjectFormat's ObjectIdentifier's IdentifierQualifier.
DataObjectFormatObjectReference[Index]	Specifies the DataObjectFormat's ObjectReference.
DetachedResourceURI	Specifies a detached resource URI.
EnvelopingObjectEncoding	Specifies the enveloping object encoding.
EnvelopingObjectID	Specifies the enveloping object identifier.
EnvelopingObjectMimeType	Specifies the enveloping object MIME type.
ExclusiveCanonicalizationPrefix	Specifies the exclusive canonicalization prefix.
ForceCompleteChainValidation	Whether to check the CA certificates when the signing certificate is invalid.
ForceCompleteChainValidationForTrusted	Whether to continue with the full validation up to the root CA certificate for mid-level trust anchors.
GracePeriod	Specifies a grace period to apply during revocation information checks.
HMACKey	The key value for HMAC.
HMACOutputLength	TBD.
IDAttributeName	Specifies the custom name of ID attribute.
IDAttributeNamespaceURI	Specifies the custom namespace URI of ID attribute.
IgnoreOCSPNoCheckExtension	Whether OCSP NoCheck extension should be ignored.
IgnoreSystemTrust	Whether trusted Windows Certificate Stores should be treated as trusted.
IgnoreTimestampFailure	Whether to ignore time-stamping failure during signing.
ImplicitlyTrustSelfSignedCertificates	Whether to trust self-signed certificates.
IncludeKey	Specifies whether to include the signing key to the signature.
IncludeKeyValue	Specifies whether the key value must be included to the signature.
IncludeKnownRevocationInfoToSignature	Whether to include custom revocation info to the signature.
InclusiveNamespacesPrefixList	Specifies the InclusiveNamespaces PrefixList.
InputType	Specifies the Input type.
KeyInfoCustomXML	The custom XML content for KeyInfo element.
KeyInfoDetails	Specifies the signing key info details to include to the signature.
KeyInfoID	Specifies the ID for KeyInfo element.
KeyName	Contains information about the key used for signing.
ManifestCount	The number of the manifest elements.
ManifestID[Index]	The ID of the manifest element.
ManifestObjectIndex[Index]	The object element index to which the manifest element belongs.
ManifestXML[Index]	The XML content of the manifest element.
ObjectCount	The number of the object elements.
ObjectEncoding[Index]	The Encoding of the object element.
ObjectID[Index]	The ID of the object element.
ObjectMimeType[Index]	The MIME type of the object element.
ObjectXML[Index]	The XML content of the object element.
ProductionPlace	Identifies the place of the signature production.
PromoteLongOCSPResponses	Whether long OCSP responses are requested.
QualifyingPropertiesID	Specifies the ID for QualifyingProperties element.
RefsTimestampType	Specifies references timestamp type to include to the signature.
SignatureCompliance	Specifies the signature compliance mode.
SignatureID	Specifies the ID for Signature element.
SignaturePrefix	Specifies the signature prefix.
SignaturePropertiesCount	The number of the signature properties elements.
SignaturePropertiesID[Index]	The ID of the signature properties element.
SignaturePropertiesObjectIndex[Index]	The object element index to which the signature properties element belongs.
SignaturePropertiesXML[Index]	The XML content of the signature properties element.
SignaturePropertyCount	The number of the signature property elements.
SignaturePropertyID[Index]	The ID of the signature properties element.
SignaturePropertyPropertiesIndex[Index]	The signature properties element index to which the signature property element belongs.
SignaturePropertyTarget[Index]	The Target of the signature properties element.
SignaturePropertyXML[Index]	The XML content of the signature property element.
SignatureValue	Contains the SignatureValue.
SignatureValueID	Specifies the ID for SignatureValue element.
SignedInfoID	Specifies the ID for SignedInfo element.
SignedPropertiesID	Specifies the ID for SignedProperties element.
SignedPropertiesReferenceCanonicalizationMethod	Specifies the canonicalization method used in SignedProperties reference.
SignedPropertiesReferenceHashAlgorithm	Specifies the hash algorithm used in SignedProperties reference.
SignedPropertiesReferenceID	Specifies the ID for Reference element that points to SignedProperties element.
SignedPropertiesReferenceInclusiveNamespacesPrefixList	Specifies the InclusiveNamespaces PrefixList used in SignedProperties reference.
SignedPropertiesReferenceIndex	Specifies the index of SignedProperties reference.
SignedSignaturePropertiesID	Specifies the ID for SignedSignatureProperties element.
SigningCertificatesHashAlgorithm	Specifies the hash algorithm used for SigningCertificates.
SigPolicyDescription	signature policy description.
SigPolicyExplicitText	The explicit text of the user notice.
SigPolicyHash	The hash value of the signature policy.
SigPolicyHashAlgorithm	Specifies the hash algorithm used to compute the signature policy hash.
SigPolicyID	Identifies the signature policy.
SigPolicyNoticeNumbers	Contains user notice numbers.
SigPolicyNoticeOrganization	The organization part of the NoticeReference qualifier.
SigPolicyURI	Signature policy URI.
TempPath	Location where the temporary files are stored.
TimestampCanonicalizationMethod	Specifies canonicalization method used in timestamp.
TimestampValidationDataDetails	Specifies timestamp validation data details to include to the signature.
TLSChainValidationDetails	Contains the advanced details of the TLS server certificate validation.
TLSChainValidationResult	Contains the result of the TLS server certificate validation.
TLSClientAuthRequested	Indicates whether the TLS server requests client authentication.
TLSValidationLog	Contains the log of the TLS server certificate validation.
TolerateMinorChainIssues	Whether to tolerate minor chain issues.
TspHashAlgorithm	Sets a specific hash algorithm for use with the timestamping service.
UseHMACSigning	Whether to use HMAC signing.
UseMicrosoftCTL	Enables or disables automatic use of Microsoft online certificate trust list.
UsePSS	Whether to use RSASSA-PSS algorithm.
UseSystemCertificates	Enables or disables the use of the system certificates.
UseValidationCache	Enables or disable the use of the product-wide certificate chain validation cache.
ValidationDataRefsDetails	Specifies validation data references details to include to the signature.
ValidationDataRefsHashAlgorithm	Specifies the hash algorithm used in validation data references.
ValidationDataValuesDetails	Specifies validation data values details to include to the signature.
WriteBOM	Specifies whether byte-order mark should be written when saving the document.
XAdESPrefix	Specifies the XAdES prefix.
XAdESv141Prefix	Specifies the XAdES v1.4.1 prefix.
XMLFormatting	Specifies the signature XML formatting.
CheckKeyIntegrityBeforeUse	Enables or disable private key integrity check before use.
CookieCaching	Specifies whether a cookie cache should be used for HTTP(S) transports.
Cookies	Gets or sets local cookies for the component (supported for HTTPClient, RESTClient and SOAPClient only).
DefDeriveKeyIterations	Specifies the default key derivation algorithm iteration count.
EnableClientSideSSLFFDHE	Enables or disables finite field DHE key exchange support in TLS clients.
GlobalCookies	Gets or sets global cookies for all the HTTP transports.
HttpUserAgent	Specifies the user agent name to be used by all HTTP clients.
LogDestination	Specifies the debug log destination.
LogDetails	Specifies the debug log details to dump.
LogFile	Specifies the debug log filename.
LogFilters	Specifies the debug log filters.
LogFlushMode	Specifies the log flush mode.
LogLevel	Specifies the debug log level.
LogMaxEventCount	Specifies the maximum number of events to cache before further action is taken.
LogRotationMode	Specifies the log rotation mode.
MaxASN1BufferLength	Specifies the maximal allowed length for ASN.1 primitive tag data.
MaxASN1TreeDepth	Specifies the maximal depth for processed ASN.1 trees.
OCSPHashAlgorithm	Specifies the hash algorithm to be used to identify certificates in OCSP requests.
UseOwnDNSResolver	Specifies whether the client components should use own DNS resolver.
UseSharedSystemStorages	Specifies whether the validation engine should use a global per-process copy of the system certificate stores.
UseSystemOAEPAndPSS	Enforces or disables the use of system-driven RSA OAEP and PSS computations.
UseSystemRandom	Enables or disables the use of the OS PRNG.