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using System.Collections.Generic;
using System.IO;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.IO;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities;
namespace Org.BouncyCastle.Cms
{
/// <remarks>
/// General class for generating a CMS enveloped-data message.
///
/// A simple example of usage.
///
/// <pre>
/// CmsEnvelopedDataGenerator fact = new CmsEnvelopedDataGenerator();
///
/// fact.AddKeyTransRecipient(cert);
///
/// CmsEnvelopedData data = fact.Generate(content, algorithm);
/// </pre>
/// </remarks>
public class CmsEnvelopedDataGenerator
: CmsEnvelopedGenerator
{
public CmsEnvelopedDataGenerator()
{
}
/// <summary>Constructor allowing specific source of randomness</summary>
/// <param name="random">Instance of <c>SecureRandom</c> to use.</param>
public CmsEnvelopedDataGenerator(SecureRandom random)
: base(random)
{
}
/// <summary>
/// Generate an enveloped object that contains a CMS Enveloped Data
/// object using the passed in key generator.
/// </summary>
private CmsEnvelopedData Generate(
CmsProcessable content,
string encryptionOid,
CipherKeyGenerator keyGen)
{
AlgorithmIdentifier encAlgId = null;
KeyParameter encKey;
Asn1OctetString encContent;
try
{
byte[] encKeyBytes = keyGen.GenerateKey();
encKey = ParameterUtilities.CreateKeyParameter(encryptionOid, encKeyBytes);
Asn1Encodable asn1Params = GenerateAsn1Parameters(encryptionOid, encKeyBytes);
ICipherParameters cipherParameters;
encAlgId = GetAlgorithmIdentifier(
encryptionOid, encKey, asn1Params, out cipherParameters);
IBufferedCipher cipher = CipherUtilities.GetCipher(encryptionOid);
cipher.Init(true, new ParametersWithRandom(cipherParameters, m_random));
MemoryStream bOut = new MemoryStream();
using (var cOut = new CipherStream(bOut, null, cipher))
{
content.Write(cOut);
}
encContent = new BerOctetString(bOut.ToArray());
}
catch (SecurityUtilityException e)
{
throw new CmsException("couldn't create cipher.", e);
}
catch (InvalidKeyException e)
{
throw new CmsException("key invalid in message.", e);
}
catch (IOException e)
{
throw new CmsException("exception decoding algorithm parameters.", e);
}
Asn1EncodableVector recipientInfos = new Asn1EncodableVector();
foreach (RecipientInfoGenerator rig in recipientInfoGenerators)
{
try
{
recipientInfos.Add(rig.Generate(encKey, m_random));
}
catch (InvalidKeyException e)
{
throw new CmsException("key inappropriate for algorithm.", e);
}
catch (GeneralSecurityException e)
{
throw new CmsException("error making encrypted content.", e);
}
}
EncryptedContentInfo eci = new EncryptedContentInfo(
CmsObjectIdentifiers.Data,
encAlgId,
encContent);
Asn1Set unprotectedAttrSet = null;
if (unprotectedAttributeGenerator != null)
{
Asn1.Cms.AttributeTable attrTable = unprotectedAttributeGenerator.GetAttributes(
new Dictionary<CmsAttributeTableParameter, object>());
unprotectedAttrSet = new BerSet(attrTable.ToAsn1EncodableVector());
}
ContentInfo contentInfo = new ContentInfo(
CmsObjectIdentifiers.EnvelopedData,
new EnvelopedData(null, new DerSet(recipientInfos), eci, unprotectedAttrSet));
return new CmsEnvelopedData(contentInfo);
}
/// <summary>Generate an enveloped object that contains an CMS Enveloped Data object.</summary>
public CmsEnvelopedData Generate(
CmsProcessable content,
string encryptionOid)
{
try
{
CipherKeyGenerator keyGen = GeneratorUtilities.GetKeyGenerator(encryptionOid);
keyGen.Init(new KeyGenerationParameters(m_random, keyGen.DefaultStrength));
return Generate(content, encryptionOid, keyGen);
}
catch (SecurityUtilityException e)
{
throw new CmsException("can't find key generation algorithm.", e);
}
}
public CmsEnvelopedData Generate(CmsProcessable content, ICipherBuilderWithKey cipherBuilder)
{
//AlgorithmIdentifier encAlgId = null;
KeyParameter encKey;
Asn1OctetString encContent;
try
{
encKey = (KeyParameter) cipherBuilder.Key;
MemoryStream collector = new MemoryStream();
var cipher = cipherBuilder.BuildCipher(collector);
using (var bOut = cipher.Stream)
{
content.Write(bOut);
}
encContent = new BerOctetString(collector.ToArray());
}
catch (SecurityUtilityException e)
{
throw new CmsException("couldn't create cipher.", e);
}
catch (InvalidKeyException e)
{
throw new CmsException("key invalid in message.", e);
}
catch (IOException e)
{
throw new CmsException("exception decoding algorithm parameters.", e);
}
Asn1EncodableVector recipientInfos = new Asn1EncodableVector();
foreach (RecipientInfoGenerator rig in recipientInfoGenerators)
{
try
{
recipientInfos.Add(rig.Generate(encKey, m_random));
}
catch (InvalidKeyException e)
{
throw new CmsException("key inappropriate for algorithm.", e);
}
catch (GeneralSecurityException e)
{
throw new CmsException("error making encrypted content.", e);
}
}
EncryptedContentInfo eci = new EncryptedContentInfo(
CmsObjectIdentifiers.Data,
(AlgorithmIdentifier) cipherBuilder.AlgorithmDetails,
encContent);
Asn1Set unprotectedAttrSet = null;
if (unprotectedAttributeGenerator != null)
{
Asn1.Cms.AttributeTable attrTable = unprotectedAttributeGenerator.GetAttributes(
new Dictionary<CmsAttributeTableParameter, object>());
unprotectedAttrSet = new BerSet(attrTable.ToAsn1EncodableVector());
}
ContentInfo contentInfo = new ContentInfo(
CmsObjectIdentifiers.EnvelopedData,
new EnvelopedData(null, new DerSet(recipientInfos), eci, unprotectedAttrSet));
return new CmsEnvelopedData(contentInfo);
}
/// <summary>Generate an enveloped object that contains an CMS Enveloped Data object.</summary>
public CmsEnvelopedData Generate(
CmsProcessable content,
string encryptionOid,
int keySize)
{
try
{
CipherKeyGenerator keyGen = GeneratorUtilities.GetKeyGenerator(encryptionOid);
keyGen.Init(new KeyGenerationParameters(m_random, keySize));
return Generate(content, encryptionOid, keyGen);
}
catch (SecurityUtilityException e)
{
throw new CmsException("can't find key generation algorithm.", e);
}
}
}
}
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