WriteProtection.AlgorithmIdExtensibility Property

Cryptographic Algorithm Extensibility.Represents the attribte in schema: w:algIdExt

Namespace:  DocumentFormat.OpenXml.Wordprocessing
Assembly:  DocumentFormat.OpenXml (in DocumentFormat.OpenXml.dll)


<SchemaAttrAttribute(, "algIdExt")> _
Public Property AlgorithmIdExtensibility As HexBinaryValue
Dim instance As WriteProtection
Dim value As HexBinaryValue

value = instance.AlgorithmIdExtensibility

instance.AlgorithmIdExtensibility = value
[SchemaAttrAttribute(, "algIdExt")]
public HexBinaryValue AlgorithmIdExtensibility { get; set; }

Property Value

Type: DocumentFormat.OpenXml.HexBinaryValue
Returns StringValue.


The following information from the ECMA International Standard ECMA-376 can be useful when working with this class.

Specifies that a cryptographic algorithm which was not defined by the Office Open XML Standard has been used to generate the hash value stored with this document.

This value, when present, shall be interpreted based on the value of the algIdExtSource attribute in order to determine the algorithm used, which shall be application defined. This extensibility affords the fact that with exponentially increasing computing power, documents created in the future will likely need to use as yet undefined hashing algorithms in order to remain secure.

If this value is present, the cryptAlgorithmClass, cryptAlgorithmType, and cryptAlgorithmSid attribute values shall be ignored in favor of the algorithm defined by this attribute.

Consider a WordprocessingML document with the following information stored in one of its protection elements:

<w:… w:algIdExt="0000000A" 
  w:hash="9oN7nWkCAyEZib1RomSJTjmPpCY=" />

The algIdExt attribute value of 0000000A specifies that the algorithm with hex code A shall be used as defined by the Contoso application.

The possible values for this attribute are defined by the ST_LongHexNumber simple type.

See Also


WriteProtection Class

WriteProtection Members

DocumentFormat.OpenXml.Wordprocessing Namespace