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GroupDocs.Signature provides ability to secure Metadata signatures with standard or custom encryption. Standard encryption is implemented over class SymmetricEncryption class. Creation of this object expects 3 arguments like encryption algorithm enumeration SymmetricAlgorithmType with one of following values (DES, TripleDES, RC2, Rijndael), string value key and string value salt.
Here are the steps to secure Metadata string values with standard encryption with GroupDocs.Signature:
- Create new instance of Signature class and pass source document path or stream as a constructor parameter.
- Compose object of SymmetricEncryption class with required algorithm and secure pair key/salt
- Create objects of MetadataSignOptions class and setup property MetadataSignOptions.DataEncryption with object of SymmetricEncryption. In this case all added Metadata signatures to options collection will be encrypted.
- Alternative way to encrypt only selected Metadata signatures is to setup property MetadataSignature.DataEncryption to each signature that requires to be secured.
- Create required collection of MetadataSignature object with proper class for document type (like PdfMetadataSignature, ImageMetadataSignature, PresentationMetadataSignature, SpreadsheetMetadataSignature, WordProcessingMetadataSignature)
- Call Sign method of Signature class instance and pass MetadataSignOptions to it.
This example shows how to sign document with encrypted Metadata signatures over .
using (Signature signature = new Signature("sample.docx"))
{
// setup key and passphrase
string key = "1234567890";
string salt = "1234567890";
// create data encryption
IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
// setup options with text of signature
MetadataSignOptions options = new MetadataSignOptions()
{
};
// setup signature metadata - this text will not be encrypted
WordProcessingMetadataSignature mdAuthor = new WordProcessingMetadataSignature("Author", "Mr.Scherlock Holmes");
// setup data of document id
WordProcessingMetadataSignature mdDocId = new WordProcessingMetadataSignature("DocumentId", Guid.NewGuid().ToString());
// set encryption for separate metadata signatures for this options
mdDocId.DataEncryption = encryption
// add signatures to options
options.Signatures.Add(mdAuthor);
options.Signatures.Add(mdDocId);
// sign document to file
signature.Sign("MetadataEncryptedText.docx", options);
}
This example shows how to sign document with encrypted Metadata signatures over .
using (Signature signature = new Signature("sample.docx"))
{
// setup key and passphrase
string key = "1234567890";
string salt = "1234567890";
// create data encryption
IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
// setup options with text of signature
MetadataSignOptions options = new MetadataSignOptions()
{
// set encryption for all metadata signatures for this options
// if you need separate encryption use own MetadataSignature.DataEncryption property
DataEncryption = encryption
};
// setup signature metadata
WordProcessingMetadataSignature mdAuthor = new WordProcessingMetadataSignature("Author", "Mr.Scherlock Holmes");
// setup data of document id
WordProcessingMetadataSignature mdDocId = new WordProcessingMetadataSignature("DocumentId", Guid.NewGuid().ToString());
// add signatures to options
options.Signatures.Add(mdAuthor);
options.Signatures.Add(mdDocId);
// sign document to file
signature.Sign("MetadataEncryptedText.docx", options);
}
You may easily run the code above and see the feature in action in our GitHub examples:
- GroupDocs.Signature for .NET examples, plugins, and showcase
- GroupDocs.Signature for Java examples, plugins, and showcase
- Document Signature for .NET MVC UI Example
- Document Signature for .NET App WebForms UI Example
- Document Signature for Java App Dropwizard UI Example
- Document Signature for Java Spring UI Example
Along with the full-featured .NET library, we provide simple but powerful free online apps.
To sign PDF, Word, Excel, PowerPoint, and other documents you can use the online apps from the GroupDocs.Signature App Product Family.
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