# Sign Method (Signature Object)

Writes the XML digital signature block and computes the cryptographic hash for the signed data. This method can only be called from the OnSign event handler. Calling this method displays the Digital Signatures dialog box.

expression.Sign()

expression Required. An expression that returns a reference to a Signature object.

## Security Level

3: Can be accessed only by fully trusted forms.

## Remarks

Use the Create method of the Signatures collection to create a digital signature. Then, use the Sign method to write the digital signature.

Note This object model member is not supported when the Disable Service Pack features option on the Advanced tab of the Options dialog box in InfoPath is selected or when Microsoft Office 2003 Service Pack 1 or later is not installed. Any form that implements this object model member in its code will generate an error message if it is opened in InfoPath when service pack features are disabled or unavailable.

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