DefaultSignedAttributeTableGenerator.cs
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using System;
using System.Collections;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Utilities;
namespace Org.BouncyCastle.Cms
{
/**
* Default signed attributes generator.
*/
public class DefaultSignedAttributeTableGenerator
: CmsAttributeTableGenerator
{
private readonly IDictionary table;
/**
* Initialise to use all defaults
*/
public DefaultSignedAttributeTableGenerator()
{
table = Platform.CreateHashtable();
}
/**
* Initialise with some extra attributes or overrides.
*
* @param attributeTable initial attribute table to use.
*/
public DefaultSignedAttributeTableGenerator(
AttributeTable attributeTable)
{
if (attributeTable != null)
{
table = attributeTable.ToDictionary();
}
else
{
table = Platform.CreateHashtable();
}
}
#if SILVERLIGHT || PORTABLE
/**
* Create a standard attribute table from the passed in parameters - this will
* normally include contentType, signingTime, and messageDigest. If the constructor
* using an AttributeTable was used, entries in it for contentType, signingTime, and
* messageDigest will override the generated ones.
*
* @param parameters source parameters for table generation.
*
* @return a filled in Hashtable of attributes.
*/
protected virtual IDictionary createStandardAttributeTable(
IDictionary parameters)
{
IDictionary std = Platform.CreateHashtable(table);
DoCreateStandardAttributeTable(parameters, std);
return std;
}
#else
/**
* Create a standard attribute table from the passed in parameters - this will
* normally include contentType, signingTime, and messageDigest. If the constructor
* using an AttributeTable was used, entries in it for contentType, signingTime, and
* messageDigest will override the generated ones.
*
* @param parameters source parameters for table generation.
*
* @return a filled in Hashtable of attributes.
*/
protected virtual Hashtable createStandardAttributeTable(
IDictionary parameters)
{
Hashtable std = new Hashtable(table);
DoCreateStandardAttributeTable(parameters, std);
return std;
}
#endif
private void DoCreateStandardAttributeTable(IDictionary parameters, IDictionary std)
{
// contentType will be absent if we're trying to generate a counter signature.
if (parameters.Contains(CmsAttributeTableParameter.ContentType))
{
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.SigningTime))
{
Asn1.Cms.Attribute attr = new Asn1.Cms.Attribute(CmsAttributes.SigningTime,
new DerSet(new Time(DateTime.UtcNow)));
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;
}
}
/**
* @param parameters source parameters
* @return the populated attribute table
*/
public virtual AttributeTable GetAttributes(
IDictionary parameters)
{
IDictionary table = createStandardAttributeTable(parameters);
return new AttributeTable(table);
}
}
}