## DigitalSignatureUtil class

Provides methods for signing document.
To learn more, visit the [Work with Digital Signatures](https://docs.aspose.com/words/python-net/working-with-digital-signatures/) documentation article.




### Remarks

Since digital signature works with file content rather than Document Object Model these methods are put into a separate class.

Supported formats are:
[LoadFormat.DOC](../../aspose.words/loadformat/#DOC),
[LoadFormat.DOT](../../aspose.words/loadformat/#DOT),
[LoadFormat.DOCX](../../aspose.words/loadformat/#DOCX),
[LoadFormat.DOTX](../../aspose.words/loadformat/#DOTX),
[LoadFormat.DOCM](../../aspose.words/loadformat/#DOCM),
[LoadFormat.DOTM](../../aspose.words/loadformat/#DOTM),
[LoadFormat.ODT](../../aspose.words/loadformat/#ODT),
[LoadFormat.OTT](../../aspose.words/loadformat/#OTT).




### Methods

| Name | Description |
| --- | --- |
|[ load_signatures(file_name)](./load_signatures/#str) | Loads digital signatures from document. |
|[ load_signatures(stream)](./load_signatures/#bytesio) | Loads digital signatures from document using stream. |
|[ remove_all_signatures(src_file_name, dst_file_name)](./remove_all_signatures/#str_str) | Removes all digital signatures from source file and writes unsigned file to destination file. The following formats are compatible for digital signature removal: [LoadFormat.DOC](../../aspose.words/loadformat/#DOC), [LoadFormat.DOT](../../aspose.words/loadformat/#DOT), [LoadFormat.DOCX](../../aspose.words/loadformat/#DOCX), [LoadFormat.DOTX](../../aspose.words/loadformat/#DOTX), [LoadFormat.DOCM](../../aspose.words/loadformat/#DOCM), [LoadFormat.DOTM](../../aspose.words/loadformat/#DOTM), [LoadFormat.ODT](../../aspose.words/loadformat/#ODT), [LoadFormat.OTT](../../aspose.words/loadformat/#OTT). |
|[ remove_all_signatures(src_stream, dst_stream)](./remove_all_signatures/#bytesio_bytesio) | Removes all digital signatures from document in source stream and writes unsigned document to destination stream. **Output will be written to the start of stream and stream size will be updated with content length.** |
|[ sign(src_stream, dst_stream, cert_holder, sign_options)](./sign/#bytesio_bytesio_certificateholder_signoptions) | Signs source document using given [CertificateHolder](../certificateholder/) and [SignOptions](../signoptions/) with digital signature and writes signed document to destination stream. Supported formats are: [LoadFormat.DOC](../../aspose.words/loadformat/#DOC), [LoadFormat.DOT](../../aspose.words/loadformat/#DOT), [LoadFormat.DOCX](../../aspose.words/loadformat/#DOCX), [LoadFormat.DOTX](../../aspose.words/loadformat/#DOTX), [LoadFormat.DOCM](../../aspose.words/loadformat/#DOCM), [LoadFormat.DOTM](../../aspose.words/loadformat/#DOTM), [LoadFormat.ODT](../../aspose.words/loadformat/#ODT), [LoadFormat.OTT](../../aspose.words/loadformat/#OTT). |
|[ sign(src_file_name, dst_file_name, cert_holder, sign_options)](./sign/#str_str_certificateholder_signoptions) | Signs source document using given [CertificateHolder](../certificateholder/) and [SignOptions](../signoptions/) with digital signature and writes signed document to destination file. Supported formats are: [LoadFormat.DOC](../../aspose.words/loadformat/#DOC), [LoadFormat.DOT](../../aspose.words/loadformat/#DOT), [LoadFormat.DOCX](../../aspose.words/loadformat/#DOCX), [LoadFormat.DOTX](../../aspose.words/loadformat/#DOTX), [LoadFormat.DOCM](../../aspose.words/loadformat/#DOCM), [LoadFormat.DOTM](../../aspose.words/loadformat/#DOTM), [LoadFormat.ODT](../../aspose.words/loadformat/#ODT), [LoadFormat.OTT](../../aspose.words/loadformat/#OTT). |
|[ sign(src_stream, dst_stream, cert_holder)](./sign/#bytesio_bytesio_certificateholder) | Signs source document using given [CertificateHolder](../certificateholder/) with digital signature and writes signed document to destination stream. Supported formats are: [LoadFormat.DOC](../../aspose.words/loadformat/#DOC), [LoadFormat.DOT](../../aspose.words/loadformat/#DOT), [LoadFormat.DOCX](../../aspose.words/loadformat/#DOCX), [LoadFormat.DOTX](../../aspose.words/loadformat/#DOTX), [LoadFormat.DOCM](../../aspose.words/loadformat/#DOCM), [LoadFormat.DOTM](../../aspose.words/loadformat/#DOTM), [LoadFormat.ODT](../../aspose.words/loadformat/#ODT), [LoadFormat.OTT](../../aspose.words/loadformat/#OTT). |
|[ sign(src_file_name, dst_file_name, cert_holder)](./sign/#str_str_certificateholder) | Signs source document using given [CertificateHolder](../certificateholder/) with digital signature and writes signed document to destination file. Supported formats are: [LoadFormat.DOC](../../aspose.words/loadformat/#DOC), [LoadFormat.DOT](../../aspose.words/loadformat/#DOT), [LoadFormat.DOCX](../../aspose.words/loadformat/#DOCX), [LoadFormat.DOTX](../../aspose.words/loadformat/#DOTX), [LoadFormat.DOCM](../../aspose.words/loadformat/#DOCM), [LoadFormat.DOTM](../../aspose.words/loadformat/#DOTM), [LoadFormat.ODT](../../aspose.words/loadformat/#ODT), [LoadFormat.OTT](../../aspose.words/loadformat/#OTT). |

### Examples

Shows how to load signatures from a digitally signed document.

```python
# There are two ways of loading a signed document's collection of digital signatures using the DigitalSignatureUtil class.
# 1 -  Load from a document from a local file system filename:
digital_signatures = aw.digitalsignatures.DigitalSignatureUtil.load_signatures(file_name=MY_DIR + 'Digitally signed.docx')
# If this collection is nonempty, then we can verify that the document is digitally signed.
self.assertEqual(1, digital_signatures.count)
# 2 -  Load from a document from a FileStream:
with system_helper.io.FileStream(MY_DIR + 'Digitally signed.docx', system_helper.io.FileMode.OPEN) as stream:
    digital_signatures = aw.digitalsignatures.DigitalSignatureUtil.load_signatures(stream=stream)
    self.assertEqual(1, digital_signatures.count)
```

Shows how to remove digital signatures from a digitally signed document.

```python
# There are two ways of using the DigitalSignatureUtil class to remove digital signatures
# from a signed document by saving an unsigned copy of it somewhere else in the local file system.
# 1 - Determine the locations of both the signed document and the unsigned copy by filename strings:
aw.digitalsignatures.DigitalSignatureUtil.remove_all_signatures(src_file_name=MY_DIR + 'Digitally signed.docx', dst_file_name=ARTIFACTS_DIR + 'DigitalSignatureUtil.LoadAndRemove.FromString.docx')
# 2 - Determine the locations of both the signed document and the unsigned copy by file streams:
with system_helper.io.FileStream(MY_DIR + 'Digitally signed.docx', system_helper.io.FileMode.OPEN) as stream_in:
    with system_helper.io.FileStream(ARTIFACTS_DIR + 'DigitalSignatureUtil.LoadAndRemove.FromStream.docx', system_helper.io.FileMode.CREATE) as stream_out:
        aw.digitalsignatures.DigitalSignatureUtil.remove_all_signatures(src_stream=stream_in, dst_stream=stream_out)
# Verify that both our output documents have no digital signatures.
self.assertEqual(0, aw.digitalsignatures.DigitalSignatureUtil.load_signatures(file_name=ARTIFACTS_DIR + 'DigitalSignatureUtil.LoadAndRemove.FromString.docx').count)
self.assertEqual(0, aw.digitalsignatures.DigitalSignatureUtil.load_signatures(file_name=ARTIFACTS_DIR + 'DigitalSignatureUtil.LoadAndRemove.FromStream.docx').count)
```

### See Also

* module [aspose.words.digitalsignatures](../)