Package | flash.security |
Class | public class XMLSignatureValidator |
Inheritance | XMLSignatureValidator EventDispatcher Object |
Language Version: | ActionScript 3.0 |
Runtime Versions: | AIR 1.0 |
XMLSignatureValidator implements a subset of the W3C Recommendation for XML-Signature Syntax and Processing and should not be considered a conforming implementation. The supported subset of the recommendation includes:
- All of the core signature syntax except KeyInfo element.
- The KeyInfo element only supports the X509Data element.
- The X509Data element only supports the X509Certificate element.
- The SHA256 digest method algorithm.
- The PKCS1 signing algorithm.
- The "Canonical XML without comments" Canonicalization Method and Transform algorithm.
- The Manifest element in additional signature syntax.
You must provide an IURIDereferencer implementation in order to verify an XML signature. This implementation class is responsible for resolving the URIs specified in the SignedInfo elements of the signature file and returning the referenced data in an object, such as a ByteArray, that implements the IDataInput interface.
In order to verify that the signing certificate chains to a trusted certificate, either
the XML signature must contain the certificates required to build the chain in X509Certificate
elements, or you must supply the certificates required to build the chain using the
addCertificate()
method.
To verify an XMLSignature:
- Create an instance of the XMLSignatureValidator class.
- Set the
uriDereferencer
property of the instance to an instance of your IURIDereferencer implementation class. - Supply DER-encoded certificates for building the certificate trust chain, if desired,
using the
addCertificate()
method. - Call the XMLSignatureValidator
verify
method, passing in the signature to be verified. - Check the
validityStatus
property after the XMLSignatureValidator object dispatches a complete event.
About signature status:
The validity of an XML signature can be valid, invalid, or unknown. The overall status depends on the verification status of the individual components of the signature file:
-
digestStatus
— The validity of the cryptographic of the signature computed over the SignedInfo element. Can bevalid
,invalid
, orunknown
. -
identityStatus
— The validity of the signing certificate. If the certificate has expired, has been revoked, or altered, the status isinvalid
. If the certificate cannot be chained to a trusted root certificate, the status isunknown
. The certificate is not checked if the digest is invalid. If not checked, the status will be reported asunknown
. -
referencesStatus
— The validity of the data addressed by the references in the SignedInfo element of the signature file. Can bevalid
,invalid
, orunknown
. The references are not checked if the digest or certificate is invalid. Reference checking can also be skipped based on the setting of thereferencesValidationSetting
property. If not checked, the status will be reported asunknown
.
The signature validity reported by the validityStatus
property can be:
-
valid
— IfreferencesStatus
,digestStatus
, andidentityStatus
are allvalid
. -
invalid
— If any individual status isinvalid
. -
unknown
— IfreferencesStatus
,digestStatus
, oridentityStatus
isunknown
.
Canonicalization limitations:
The XML engine in AIR does not always produce the expected XML string when canonicalizing an XML document. For this reason, it is recommended that you avoid putting inter-element whitespace in enveloped or detached signature documents and do not redefine namespaces inside a signature document. In both cases, AIR may not recreate the document with the same character sequence as the original and, therefore, validation will fail.
See also
Property | Defined By | ||
---|---|---|---|
constructor : Object
A reference to the class object or constructor function for a given object instance. | Object | ||
digestStatus : String [read-only]
The validity status of the cryptographic signature computed over the
SignedInfo element. | XMLSignatureValidator | ||
identityStatus : String [read-only]
The validity status of the signing certificate. | XMLSignatureValidator | ||
prototype : Object [static]
A reference to the prototype object of a class or function object. | Object | ||
referencesStatus : String [read-only]
The validity status of the data in the references in the SignedInfo
element. | XMLSignatureValidator | ||
referencesValidationSetting : String
Specifies the conditions under which references are checked. | XMLSignatureValidator | ||
revocationCheckSetting : String
Specifies how certificate revocation is checked. | XMLSignatureValidator | ||
signerCN : String [read-only]
The Common Name field of the signing certificate. | XMLSignatureValidator | ||
signerDN : String [read-only]
The Distinguished Name field of the signing certificate. | XMLSignatureValidator | ||
signerExtendedKeyUsages : Array [read-only]
An array containing the Extended Key Usages OIDs listed in the signing certificate. | XMLSignatureValidator | ||
signerTrustSettings : Array [read-only]
An array containing the trust settings of the signing certificate. | XMLSignatureValidator | ||
uriDereferencer : IURIDereferencer
The IURIDereferencer implementation. | XMLSignatureValidator | ||
useSystemTrustStore : Boolean
Specifies that certificates in the system trust store are used for chain building. | XMLSignatureValidator | ||
validityStatus : String [read-only]
The validity status of a verified XML signature. | XMLSignatureValidator |
Method | Defined By | ||
---|---|---|---|
Creates an XMLSignatureValidator object. | XMLSignatureValidator | ||
Adds an x509 certificate for chain building. | XMLSignatureValidator | ||
addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void
Registers an event listener object with an EventDispatcher object so that the listener
receives notification of an event. | EventDispatcher | ||
Dispatches an event into the event flow. | EventDispatcher | ||
Checks whether the EventDispatcher object has any listeners registered for a specific type
of event. | EventDispatcher | ||
Indicates whether an object has a specified property defined. | Object | ||
Indicates whether an instance of the Object class is in the prototype chain of the object specified
as the parameter. | Object | ||
Indicates whether the specified property exists and is enumerable. | Object | ||
Removes a listener from the EventDispatcher object. | EventDispatcher | ||
Sets the availability of a dynamic property for loop operations. | Object | ||
Returns the string representation of this object, formatted according to locale-specific conventions. | Object | ||
Returns the string representation of the specified object. | Object | ||
Returns the primitive value of the specified object. | Object | ||
Verifies the specified signature. | XMLSignatureValidator | ||
Checks whether an event listener is registered with this EventDispatcher object or any of
its ancestors for the specified event type. | EventDispatcher |
Event | Summary | Defined By | ||
---|---|---|---|---|
[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active. | EventDispatcher | |||
Dispatched when verification is complete. | XMLSignatureValidator | |||
[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive. | EventDispatcher | |||
Dispatched if verification cannot complete because of errors. | XMLSignatureValidator |
digestStatus | property |
digestStatus:String
[read-only] Runtime Versions: | AIR 1.0 |
The validity status of the cryptographic signature computed over the
SignedInfo
element.
The status is:
valid
— If signature is cryptographically valid.invalid
— If the digest has been altered after signing.unknown
— If theverify()
method has not been called.
Note: If the digestStatus
is invalid, the identityStatus
and referencesStatus
are not checked and will be reported as unknown
.
Implementation
public function get digestStatus():String
Throws
IllegalOperationError — If accessed while a signature is being validated.
|
identityStatus | property |
identityStatus:String
[read-only] Runtime Versions: | AIR 1.0 |
The validity status of the signing certificate.
The status can be:
valid
— The certificate has not expired, has not failed a revocation check and chains to a trusted root certificate.unknown
— The certificate has not expired and has not failed a revocation check, but does not chain to a trusted root certificate. A status ofunknown
will also be reported when the status has not been verified, either because theverify()
method has not been called or because the cryptographic signature of the SignedInfo element (digestStatus
) is invalid.invalid
— The certificate has expired or fails a revocation check.
The certificates added using the addCertificate()
method
and the settings of the revocationCheckSetting
and the useSystemTrustStore
properties can change whether a certificate is considered valid.
Note: If the identityStatus
is invalid, the referencesStatus
is not checked
and will be reported as unknown
. In addition, references are not checked when the identityStatus
is unknown unless the referencesValidationSetting
is validOrUnknownIdentity
Implementation
public function get identityStatus():String
Throws
IllegalOperationError — If accessed while a signature is being validated.
|
See also
Example ( How to use this example )
import flash.security.XMLSignatureValidator; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate a signature... var identityResult:String = verifier.identityStatus;
referencesStatus | property |
referencesStatus:String
[read-only] Runtime Versions: | AIR 1.0 |
The validity status of the data in the references in the SignedInfo
element.
The status can be:
valid
— If all references are valid.invalid
— If any reference is invalid.unknown
— If not verified. References can remain unverified in the following circumstances:- the
verify()
method has not been called - the cryptographic signature of the SignedInfo element (
digestStatus
) is invalid. - the signing certificate (
identityStatus
) is invalid referencesValidationSetting
isvalidIdentity
(which is the default setting) and theidentityStatus
of the signing certificate is unknown.- the
referencesValidationSetting
isnever
.
- the
Important: External resources are not validated unless they are referenced directly in a SignedInfo element within the signature document. External resources referred to by a secondary reference are not validated. For example, if an XML signature signs a manifest element, only the integrity of the manifest element itself is verified. The files listed in the manifest are not checked.
Implementation
public function get referencesStatus():String
Throws
IllegalOperationError — If accessed while a signature is being validated.
|
See also
Example ( How to use this example )
import flash.security.XMLSignatureValidator; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate a signature... var dataResult:String = verifier.referencesStatus;
referencesValidationSetting | property |
referencesValidationSetting:String
Runtime Versions: | AIR 1.5 |
Specifies the conditions under which references are checked.
Use constants defined in the ReferencesValidationSetting class to set this property. The settings include:
ReferencesValidationSetting.VALID_IDENTITY
— Check references only if the signing certificate is valid and chains to a trusted root. This is the default setting.ReferencesValidationSetting.VALID_OR_UNKNOWN_IDENTITY
— Check references if the signing certificate is valid, even if it does not chain to a trusted root.ReferencesValidationSetting.NEVER
— Never check references.
Use the default, validIdentity
, setting with signatures signed with a commercial certificate or when you
supply your own certificate as a trust anchor with the addCertificate()
method. This
setting avoids the overhead of checking reference validity when the signed document will be rejected anyway.
Use the validOrUnknownIdentity
setting with signatures signed with self-signed certificates. This setting allows you to
validate that the signed data has not been altered, but does not provide any assurances about the identity
of the signer.
Use the never
setting to avoid the overhead of validating references when such validation is not important in the
context of your application.
Implementation
public function get referencesValidationSetting():String
public function set referencesValidationSetting(value:String):void
Throws
IllegalOperationError — If set while a signature is being validated.
| |
ArgumentError — if the setting parameter contains a value not defined in the ReferencesValidationSetting class.
|
See also
Example ( How to use this example )
import flash.security.ReferencesValidationSetting; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); verifier.referencesValidationSetting = ReferencesValidationSetting.VALID_OR_UNKNOWN_IDENTITY;
revocationCheckSetting | property |
revocationCheckSetting:String
Runtime Versions: | AIR 1.0 |
Specifies how certificate revocation is checked.
Use constants defined in the RevocationSettings class to set this property. The settings include:
RevocationCheckSettings.NEVER
— Do not check certificate revocation.RevocationCheckSettings.BEST_EFFORT
— Check certificate revocation, if revocation information is available and the revocation status can be obtained. If revocation status cannot be positively determined, the certificate is not rejected.RevocationCheckSettings.REQUIRED_IF_AVAILABLE
— If the certificate includes revocation information, the revocation status must be positively determined to validate the certificate.RevocationCheckSettings.ALWAYS_REQUIRED
— Always check certificate revocation. Certificates without revocation information are rejected.
Implementation
public function get revocationCheckSetting():String
public function set revocationCheckSetting(value:String):void
Throws
IllegalOperationError — If set while a signature is being validated.
|
See also
signerCN | property |
signerCN:String
[read-only] Runtime Versions: | AIR 1.0 |
The Common Name field of the signing certificate.
Implementation
public function get signerCN():String
Example ( How to use this example )
var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate a signature... var commonName:String = verifier.signerCN;
signerDN | property |
signerDN:String
[read-only] Runtime Versions: | AIR 1.0 |
The Distinguished Name field of the signing certificate.
Implementation
public function get signerDN():String
Example ( How to use this example )
var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate a signature... var distinguishedName:String = verifier.signerDN;
signerExtendedKeyUsages | property |
signerExtendedKeyUsages:Array
[read-only] Runtime Versions: | AIR 1.0 |
An array containing the Extended Key Usages OIDs listed in the signing certificate.
Each extended key usage is reported in numeric OID form.
Implementation
public function get signerExtendedKeyUsages():Array
Throws
IllegalOperationError — If accessed while a signature is being validated.
|
Example ( How to use this example )
import flash.security.XMLSignatureValidator; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate a signature... var extendedKeyOIDs:Array = verifier.signerExtendedKeyUsages;
signerTrustSettings | property |
signerTrustSettings:Array
[read-only] Runtime Versions: | AIR 1.0 |
An array containing the trust settings of the signing certificate.
Trust settings are derived from the system and the key usage OIDs embedded in the certificate. Constants for the strings representing the recognized trust settings are defined in the SignerTrustSettings class.
The signerTrustSettings
array of an unknown
or
invalid
certificate is empty.
Modifying the array does not change the certificate trust settings.
Implementation
public function get signerTrustSettings():Array
Throws
IllegalOperationError — If accessed while a signature is being validated.
|
See also
Example ( How to use this example )
import flash.security.XMLSignatureValidator; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate a signature... var certificateTrustedFor:Array = verifier.signerTrustSettings;
uriDereferencer | property |
uriDereferencer:IURIDereferencer
Runtime Versions: | AIR 1.0 |
The IURIDereferencer implementation.
An IURIDereferencer implementation must be provided before attempting to verify a signature.
Implementation
public function get uriDereferencer():IURIDereferencer
public function set uriDereferencer(value:IURIDereferencer):void
Throws
IllegalOperationError — If set while a signature is being validated.
|
See also
Example ( How to use this example )
import com.example.SignedMessageDereferencer; //A custom class implementing IURIDereferencer var verifier:XMLSignatureValidator = new XMLSignatureValidator(); verifier.uriDereferencer = new SignedMessageDereferencer();
useSystemTrustStore | property |
useSystemTrustStore:Boolean
Runtime Versions: | AIR 1.0 |
Specifies that certificates in the system trust store are used for chain building.
If true
, then the trust anchors in the system trust store
are used as trusted roots. The system trust store is not used by default.
Implementation
public function get useSystemTrustStore():Boolean
public function set useSystemTrustStore(value:Boolean):void
Throws
IllegalOperationError — If set while a signature is being validated.
|
Example ( How to use this example )
var verifier:XMLSignatureValidator = new XMLSignatureValidator(); verifier.useSystemTrustStore = true;
validityStatus | property |
validityStatus:String
[read-only] Runtime Versions: | AIR 1.0 |
The validity status of a verified XML signature.
The XML signature is verified by validating the the cryptographic signature of the SignedInfo element,
the signing certificate, and the data addressed by the references in the SignedInfo element.
The validity of each of these elements is reported individually by the digestStatus
,
identityStatus()
, and referencesStatus
properties, respectively.
The validity of an XML signature can be valid, invalid, or unknown. The overall status depends on the verification status of the individual components of the signature file:
digestStatus
— The validity of the cryptographic signature computed over the SignedInfo element.identityStatus
— The validity of the signing certificate.referencesStatus
— The validity of the digest of the references in the signature SignedInfo element.
The signature validity reported by the validityStatus
property can be:
valid
— IfreferencesStatus
,digestStatus
, andidentityStatus
are allvalid
.invalid
— If any individual status isinvalid
.unknown
— If any individual status isunknown
.
Implementation
public function get validityStatus():String
Throws
IllegalOperationError — If accessed while a signature is being validated.
|
See also
Example ( How to use this example )
import flash.security.XMLSignatureValidator; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //validate the signature... var validationResult:String = verifier.validityStatus;
XMLSignatureValidator | () | Constructor |
public function XMLSignatureValidator()
Runtime Versions: | AIR 1.0 |
Creates an XMLSignatureValidator object.
You must set the uriDereferencer
property before calling the verify()
method of the new object.
See also
Example ( How to use this example )
import com.example.EnvelopedDereferencer; //Your custom IURIDereferencer implementation //Create the object var verifier:XMLSignatureValidator = new XMLSignatureValidator(); //Provide the IURIDerferencer verifier.uriDereferencer = new EnvelopedDereferencer(xmlDoc); //Set validation options verifier.referencesValidationSetting = ReferencesValidationSetting.VALID_OR_UNKNOWN_IDENTITY; verifier.revocationCheckSetting = RevocationCheckSettings.NEVER; verifier.useSystemTrustStore = true; //Add listeners to handle results verifier.addEventListener(Event.COMPLETE, verificationComplete); verifier.addEventListener(ErrorEvent.ERROR, verificationError);
addCertificate | () | method |
public function addCertificate(cert:ByteArray, trusted:Boolean):*
Runtime Versions: | AIR 1.0 |
Adds an x509 certificate for chain building.
The certificate added must be a DER-encoded x509 certificate.
If the trusted
parameter is true
, the
certificate is considered a trust anchor.
Note: An XML signature may include certificates for building the signer's certificate chain. The XMLSignatureValidator class uses these certificates for chain building, but not as trusted roots (by default).
Parameters
cert:ByteArray — A ByteArray object containing a DER-encoded x509 digital certificate.
| |
trusted:Boolean — Set to true to designate this certificate as a trust anchor.
|
* |
Throws
IllegalOperationError — If called while a signature is being validated.
|
Example ( How to use this example )
import flash.utils.ByteArray; var verifier:XMLSignatureValidator = new XMLSignatureValidator(); var certificate:ByteArray = new ByteArray(); var certFile:File = new File("certificate.cer"); var certFileStream:FileStream = new FileStream(); certFileStream.open(certFile, FileMode.READ); certFileStream.readBytes(certificate, 0, certFileStream.bytesAvailable); verifier.addCertificate(certificate, true);
verify | () | method |
public function verify(signature:XML):void
Language Version: | ActionScript 3.0 |
Runtime Versions: | AIR 1.0 |
Verifies the specified signature.
Verification is asynchronous. The XMLSignatureValidator object dispatches
a complete
event when verification completes successfully or
an error
event if verification cannot complete because of errors.
The verification process cannot be cancelled. While a verification process is under way,
subsequent calls to the verify()
method fail. After the current verification
check is complete, you can call the verify()
method again.
Note: Because the XMLSignatureValidator only implements a subset of the W3C recommendation for XML Signature Syntax and Processing, not all valid XML signatures can be verified.
Parameters
signature:XML — The XML signature to verify.
|
Events
complete: — Dispatched when verification completes successfully.
| |
error: — Dispatched if the verification of references encounters an error.
|
Throws
IllegalOperationError — If called while a signature is being validated.
| |
Error — If other errors are encountered, such as non-well-formed XML or
unsupported elements in the signature file.
|
Example ( How to use this example )
verify()
method.
(The example assumes that the IURIDereferencer implementation is appropriate for the signature.)
import flash.filesystem.File; import flash.filesystem.FileStream; import com.example.SignedMessageDereferencer; //Your IURIDereferencer implementation const xmlSignatureNS:Namespace = new Namespace( "http://www.w3.org/2000/09/xmldsig#" ); var verifier:XMLSignatureValidator = new XMLSignatureValidator(); verifier.uriDereferencer = new SignedMessageDereferencer(); var signatureFile:File = new File( "path/to/XMLSignatureDocument.xml" ); var sigFileStream:FileStream = new FileStream(); sigFileStream.open( signatureFile, FileMode.READ ); var xmlDoc:XML = XML( sigFileStream.readUTFBytes(sigFileStream.bytesAvailable) ); var xmlSig:XML = XML( xmlDoc..xmlSignatureNS::Signature ); verifier.verify( xmlSig );
complete | Event |
flash.events.Event
property Event.type =
flash.events.Event.COMPLETE
Language Version: | ActionScript 3.0 |
Runtime Versions: | AIR 1.0 |
Dispatched when verification is complete.
A complete
event does not imply that the
signature is valid. Check the validityStatus
property of
the XMLSignatureValidator object to
determine the outcome of the signature verification.
Event.COMPLETE
constant defines the value of the type
property of a complete
event object.
This event has the following properties:
Property | Value |
---|---|
bubbles | false |
cancelable | false ; there is no default behavior to cancel. |
currentTarget | The object that is actively processing the Event object with an event listener. |
target | The network object that has completed loading. |
Example ( How to use this example )
private function verificationComplete(event:Event):void{ var validator:XMLSignatureValidator = event.target as XMLSignatureValidator; trace("Digest status: " + validator.digestStatus); trace("Identity status: " + validator.identityStatus); trace("Reference status: " + validator.referencesStatus); trace("Signature status: " + validator.validityStatus); }
See also
error | Event |
flash.events.ErrorEvent
property ErrorEvent.type =
flash.events.ErrorEvent.ERROR
Language Version: | ActionScript 3.0 |
Runtime Versions: | AIR 1.0 |
Dispatched if verification cannot complete because of errors.
Defines the value of thetype
property of an error
event object.
This event has the following properties:
Property | Value |
---|---|
bubbles | false |
cancelable | false ; there is no default behavior to cancel. |
currentTarget | The object that is actively processing the Event object with an event listener. |
target | The object experiencing a network operation failure. |
text | Text to be displayed as an error message. |
Example ( How to use this example )
private function verificationError(event:ErrorEvent):void{ trace("Verification error: " + event.text); }
SignatureValidatorExample.validateSignature( signatureFile )
,
passing in the file referencing the XML signature document to validate.
import flash.events.Event; import flash.filesystem.File; import flash.filesystem.FileStream; import flash.security.ReferencesValidationSetting; import flash.security.XMLSignatureValidator; import com.example.SignedMessageDereferencer; //A custom class implementing IURIDereferencer public class SignatureValidatorExample{ private var xmlSig:XML; private const signatureNS:Namespace = new Namespace( "http://www.w3.org/2000/09/xmldsig#" ); public static function validateSignature( signatureFile:File ):void{ try{ //Set up the XMLSignatureValidator var verifier:XMLSignatureValidator = new XMLSignatureValidator(); verifier.addEventListener( Event.COMPLETE, verificationComplete ); verifier.uriDereferencer = new SignedMessageDereferencer(); verifier.referencesValidationSetting = ReferencesValidationSetting.VALID_OR_UNKNOWN_IDENTITY; //Load the signed document var sigFileStream:FileStream = new FileStream(); sigFileStream.open( signatureFile, FileMode.READ ); var xmlDoc:XML = XML( sigFileStream.readUTFBytes(sigFileStream.bytesAvailable) ); //Get the last Signature element in the document if( xmlDoc.name().localName != "Signature" ){ var signatureList:XMLList = xmlDoc..signatureNS::Signature; xmlSig = XML( signatureList[ signatureList.length()-1 ] ); } else{ xmlSig = xmlDoc; } //Validate the signature verifier.verify( xmlSig ); }catch (e:Error){ statusDisplay.text = "Verification error.\n" + e; } } private static function verificationComplete(event:Event):void{ trace( "Signature Validity: " + verifier.validityStatus ); trace( "Digest validity: " + verifier.digestStatus ); trace( "Certificate validity: " + verifier.identityStatus ); trace( "Data validity: " + verifier.referencesStatus ); } }
Fri Mar 19 2010, 02:45 AM -07:00