using System; 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; using Org.BouncyCastle.Utilities.IO; namespace Org.BouncyCastle.Cms { /** * General class for generating a CMS enveloped-data message stream. *

* A simple example of usage. *

	*      CmsEnvelopedDataStreamGenerator edGen = new CmsEnvelopedDataStreamGenerator();
	*
	*      edGen.AddKeyTransRecipient(cert);
	*
	*      MemoryStream  bOut = new MemoryStream();
	*
	*      Stream out = edGen.Open(
	*                              bOut, CMSEnvelopedGenerator.AES128_CBC);*
	*      out.Write(data);
	*
	*      out.Close();
	* 
*

*/ public class CmsEnvelopedDataStreamGenerator : CmsEnvelopedGenerator { private object _originatorInfo = null; private object _unprotectedAttributes = null; private int _bufferSize; private bool _berEncodeRecipientSet; public CmsEnvelopedDataStreamGenerator() { } /// Constructor allowing specific source of randomness /// Instance of SecureRandom to use. public CmsEnvelopedDataStreamGenerator(SecureRandom random) : base(random) { } /// Set the underlying string size for encapsulated data. /// Length of octet strings to buffer the data. public void SetBufferSize( int bufferSize) { _bufferSize = bufferSize; } /// Use a BER Set to store the recipient information. public void SetBerEncodeRecipients( bool berEncodeRecipientSet) { _berEncodeRecipientSet = berEncodeRecipientSet; } private DerInteger Version { get { int version = (_originatorInfo != null || _unprotectedAttributes != null) ? 2 : 0; return new DerInteger(version); } } /// /// Generate an enveloped object that contains an CMS Enveloped Data /// object using the passed in key generator. /// private Stream Open( Stream outStream, string encryptionOid, CipherKeyGenerator keyGen) { byte[] encKeyBytes = keyGen.GenerateKey(); KeyParameter encKey = ParameterUtilities.CreateKeyParameter(encryptionOid, encKeyBytes); Asn1Encodable asn1Params = GenerateAsn1Parameters(encryptionOid, encKeyBytes); ICipherParameters cipherParameters; AlgorithmIdentifier encAlgID = GetAlgorithmIdentifier( encryptionOid, encKey, asn1Params, out cipherParameters); 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); } } return Open(outStream, encAlgID, cipherParameters, recipientInfos); } private Stream Open( Stream outStream, AlgorithmIdentifier encAlgID, ICipherParameters cipherParameters, Asn1EncodableVector recipientInfos) { try { // // ContentInfo // BerSequenceGenerator cGen = new BerSequenceGenerator(outStream); cGen.AddObject(CmsObjectIdentifiers.EnvelopedData); // // Encrypted Data // BerSequenceGenerator envGen = new BerSequenceGenerator( cGen.GetRawOutputStream(), 0, true); envGen.AddObject(this.Version); Stream envRaw = envGen.GetRawOutputStream(); using (var recipGen = _berEncodeRecipientSet ? (Asn1Generator)new BerSetGenerator(envRaw) : new DerSetGenerator(envRaw)) { foreach (Asn1Encodable ae in recipientInfos) { recipGen.AddObject(ae); } } BerSequenceGenerator eiGen = new BerSequenceGenerator(envRaw); eiGen.AddObject(CmsObjectIdentifiers.Data); eiGen.AddObject(encAlgID); BerOctetStringGenerator octGen = new BerOctetStringGenerator(eiGen.GetRawOutputStream(), 0, false); Stream octetOutputStream = octGen.GetOctetOutputStream(_bufferSize); IBufferedCipher cipher = CipherUtilities.GetCipher(encAlgID.Algorithm); cipher.Init(true, new ParametersWithRandom(cipherParameters, m_random)); CipherStream cOut = new CipherStream(octetOutputStream, null, cipher); return new CmsEnvelopedDataOutputStream(this, cOut, cGen, envGen, eiGen, octGen); } 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); } } /** * generate an enveloped object that contains an CMS Enveloped Data object * @throws IOException */ public Stream Open( Stream outStream, string encryptionOid) { CipherKeyGenerator keyGen = GeneratorUtilities.GetKeyGenerator(encryptionOid); keyGen.Init(new KeyGenerationParameters(m_random, keyGen.DefaultStrength)); return Open(outStream, encryptionOid, keyGen); } /** * generate an enveloped object that contains an CMS Enveloped Data object * @throws IOException */ public Stream Open( Stream outStream, string encryptionOid, int keySize) { CipherKeyGenerator keyGen = GeneratorUtilities.GetKeyGenerator(encryptionOid); keyGen.Init(new KeyGenerationParameters(m_random, keySize)); return Open(outStream, encryptionOid, keyGen); } private class CmsEnvelopedDataOutputStream : BaseOutputStream { private readonly CmsEnvelopedGenerator _outer; private readonly CipherStream _out; private readonly BerSequenceGenerator _cGen; private readonly BerSequenceGenerator _envGen; private readonly BerSequenceGenerator _eiGen; private readonly BerOctetStringGenerator _octGen; public CmsEnvelopedDataOutputStream( CmsEnvelopedGenerator outer, CipherStream outStream, BerSequenceGenerator cGen, BerSequenceGenerator envGen, BerSequenceGenerator eiGen, BerOctetStringGenerator octGen) { _outer = outer; _out = outStream; _cGen = cGen; _envGen = envGen; _eiGen = eiGen; _octGen = octGen; } public override void Write(byte[] buffer, int offset, int count) { _out.Write(buffer, offset, count); } #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER public override void Write(ReadOnlySpan buffer) { _out.Write(buffer); } #endif public override void WriteByte(byte value) { _out.WriteByte(value); } protected override void Dispose(bool disposing) { if (disposing) { _out.Dispose(); // TODO Parent context(s) should really be closed explicitly _octGen.Dispose(); _eiGen.Dispose(); if (_outer.unprotectedAttributeGenerator != null) { Asn1.Cms.AttributeTable attrTable = _outer.unprotectedAttributeGenerator.GetAttributes( new Dictionary()); Asn1Set unprotectedAttrs = new BerSet(attrTable.ToAsn1EncodableVector()); _envGen.AddObject(new DerTaggedObject(false, 1, unprotectedAttrs)); } _envGen.Dispose(); _cGen.Dispose(); } base.Dispose(disposing); } } } }