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path: root/Crypto/src/cms/DefaultAuthenticatedAttributeTableGenerator.cs
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-rw-r--r--Crypto/src/cms/DefaultAuthenticatedAttributeTableGenerator.cs90
1 files changed, 90 insertions, 0 deletions
diff --git a/Crypto/src/cms/DefaultAuthenticatedAttributeTableGenerator.cs b/Crypto/src/cms/DefaultAuthenticatedAttributeTableGenerator.cs
new file mode 100644

index 000000000..d49b1d9d2 --- /dev/null +++ b/Crypto/src/cms/DefaultAuthenticatedAttributeTableGenerator.cs
@@ -0,0 +1,90 @@ +using System; +using System.Collections; + +using Org.BouncyCastle.Asn1; +using Org.BouncyCastle.Asn1.Cms; +using Org.BouncyCastle.Utilities; + +namespace Org.BouncyCastle.Cms +{ + /** + * Default authenticated attributes generator. + */ + public class DefaultAuthenticatedAttributeTableGenerator + : CmsAttributeTableGenerator + { + private readonly IDictionary table; + + /** + * Initialise to use all defaults + */ + public DefaultAuthenticatedAttributeTableGenerator() + { + table = Platform.CreateHashtable(); + } + + /** + * Initialise with some extra attributes or overrides. + * + * @param attributeTable initial attribute table to use. + */ + public DefaultAuthenticatedAttributeTableGenerator( + AttributeTable attributeTable) + { + if (attributeTable != null) + { + table = attributeTable.ToDictionary(); + } + else + { + table = Platform.CreateHashtable(); + } + } + + /** + * Create a standard attribute table from the passed in parameters - this will + * normally include contentType and messageDigest. If the constructor + * using an AttributeTable was used, entries in it for contentType and + * messageDigest will override the generated ones. + * + * @param parameters source parameters for table generation. + * + * @return a filled in IDictionary of attributes. + */ + protected virtual IDictionary CreateStandardAttributeTable( + IDictionary parameters) + { + IDictionary std = Platform.CreateHashtable(table); + + if (!std.Contains(CmsAttributes.ContentType)) + { + DerObjectIdentifier contentType = (DerObjectIdentifier) + parameters[CmsAttributeTableParameter.ContentType]; + Asn1.Cms.Attribute attr = new Asn1.Cms.Attribute(CmsAttributes.ContentType, + new DerSet(contentType)); + std[attr.AttrType] = attr; + } + + if (!std.Contains(CmsAttributes.MessageDigest)) + { + byte[] messageDigest = (byte[])parameters[CmsAttributeTableParameter.Digest]; + Asn1.Cms.Attribute attr = new Asn1.Cms.Attribute(CmsAttributes.MessageDigest, + new DerSet(new DerOctetString(messageDigest))); + std[attr.AttrType] = attr; + } + + return std; + } + + /** + * @param parameters source parameters + * @return the populated attribute table + */ + public virtual AttributeTable GetAttributes( + IDictionary parameters) + { + IDictionary table = CreateStandardAttributeTable(parameters); + return new AttributeTable(table); + } + } +}