RecipientInfo.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / whidbey / NetFXspW7 / ndp / clr / src / ManagedLibraries / Security / System / Security / Cryptography / Pkcs / RecipientInfo.cs / 1 / RecipientInfo.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

// 
// RecipientInfo.cs 
//
 
namespace System.Security.Cryptography.Pkcs
{
    using System.Collections;
    using System.Runtime.InteropServices; 
    using System.Security.Cryptography;
    using System.Security.Cryptography.X509Certificates; 
    using System.Security.Cryptography.Xml; 
    using System.Globalization;
 
    public enum RecipientInfoType {
        Unknown      = 0,
        KeyTransport = 1,   // Must be the same as CAPI.CMSG_KEY_TRANS_RECIPIENT (1)
        KeyAgreement = 2,   // Must be the same as CAPI.CMSG_KEY_AGREE_RECIPIENT (2) 
    }
 
    internal enum RecipientSubType { 
        Unknown            = 0,
        Pkcs7KeyTransport  = 1, 
        CmsKeyTransport    = 2,
        CertIdKeyAgreement = 3,
        PublicKeyAgreement = 4,
    } 

    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public abstract class RecipientInfo { 
        private RecipientInfoType    m_recipentInfoType;
        private RecipientSubType     m_recipientSubType; 
        private SafeLocalAllocHandle m_pCmsgRecipientInfo;
        private Object               m_cmsgRecipientInfo;
        private uint                 m_index;
 
        internal RecipientInfo () {}
 
        internal RecipientInfo (RecipientInfoType recipientInfoType, RecipientSubType recipientSubType, SafeLocalAllocHandle pCmsgRecipientInfo, Object cmsgRecipientInfo, uint index) { 
            if (recipientInfoType < RecipientInfoType.Unknown || recipientInfoType > RecipientInfoType.KeyAgreement)
                recipientInfoType = RecipientInfoType.Unknown; 

            if (recipientSubType < RecipientSubType.Unknown || recipientSubType > RecipientSubType.PublicKeyAgreement)
                recipientSubType = RecipientSubType.Unknown;
 
            m_recipentInfoType = recipientInfoType;
            m_recipientSubType = recipientSubType; 
            m_pCmsgRecipientInfo = pCmsgRecipientInfo; 
            m_cmsgRecipientInfo = cmsgRecipientInfo;
            m_index = index; 
        }

        public RecipientInfoType Type {
            get { 
                return m_recipentInfoType;
            } 
        } 

        public abstract int Version { get; } 

        public abstract SubjectIdentifier RecipientIdentifier { get; }

        public abstract AlgorithmIdentifier KeyEncryptionAlgorithm { get; } 

        public abstract byte[] EncryptedKey { get; } 
 
        //
        // Internal methods. 
        //

        internal RecipientSubType SubType {
            get { 
                return m_recipientSubType;
            } 
        } 

        internal SafeLocalAllocHandle pCmsgRecipientInfo { 
            get {
                return m_pCmsgRecipientInfo;
            }
        } 

        internal Object CmsgRecipientInfo { 
            get { 
                return m_cmsgRecipientInfo;
            } 
        }

        internal uint Index {
            get { 
                return m_index;
            } 
        } 
    }
 
    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)]
    public sealed class KeyTransRecipientInfo : RecipientInfo {
        private int                     m_version;
        private SubjectIdentifier       m_recipientIdentifier; 
        private AlgorithmIdentifier     m_encryptionAlgorithm;
        private byte[]                  m_encryptedKey; 
 
        private KeyTransRecipientInfo () {}
 
        internal unsafe KeyTransRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CERT_INFO certInfo, uint index) : base(RecipientInfoType.KeyTransport, RecipientSubType.Pkcs7KeyTransport, pRecipientInfo, certInfo, index) {
            // If serial number is 0, then it is the special SKI encoding.
            int version = 2;
            byte * pb = (byte *) certInfo.SerialNumber.pbData; 
            for (int i = 0; i < certInfo.SerialNumber.cbData; i++) {
                if (*pb++ != (byte) 0) { 
                    version = 0; 
                    break;
                } 
            }

            Reset(version);
        } 

        internal unsafe KeyTransRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans, uint index) : base(RecipientInfoType.KeyTransport, RecipientSubType.CmsKeyTransport, pRecipientInfo, keyTrans, index) { 
            Reset((int) keyTrans.dwVersion); 
        }
 
        public override int Version {
            get {
                return m_version;
            } 
        }
 
        public override SubjectIdentifier RecipientIdentifier { 
            get {
                if (m_recipientIdentifier == null) { 
                    if (this.SubType == RecipientSubType.CmsKeyTransport) {
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) CmsgRecipientInfo;
                        m_recipientIdentifier = new SubjectIdentifier(keyTrans.RecipientId);
                    } 
                    else {
                        CAPI.CERT_INFO certInfo = (CAPI.CERT_INFO) CmsgRecipientInfo; 
                        m_recipientIdentifier = new SubjectIdentifier(certInfo); 
                    }
                } 

                return m_recipientIdentifier;
            }
        } 

        public override AlgorithmIdentifier KeyEncryptionAlgorithm { 
            get { 
                if (m_encryptionAlgorithm == null) {
                    if (this.SubType == RecipientSubType.CmsKeyTransport) { 
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) CmsgRecipientInfo;
                        m_encryptionAlgorithm = new AlgorithmIdentifier(keyTrans.KeyEncryptionAlgorithm);
                    }
                    else { 
                        CAPI.CERT_INFO certInfo = (CAPI.CERT_INFO) CmsgRecipientInfo;
                        m_encryptionAlgorithm = new AlgorithmIdentifier(certInfo.SignatureAlgorithm); 
                    } 
                }
 
                return m_encryptionAlgorithm;
            }
        }
 
        public override byte[] EncryptedKey {
            get { 
                if (m_encryptedKey.Length == 0) { 
                    // CAPI does not provide a way to retrieve encrypted key for PKCS 7 message.
                    if (this.SubType == RecipientSubType.CmsKeyTransport) { 
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) CmsgRecipientInfo;
                        if (keyTrans.EncryptedKey.cbData > 0) {
                            m_encryptedKey = new byte[keyTrans.EncryptedKey.cbData];
                            Marshal.Copy(keyTrans.EncryptedKey.pbData, m_encryptedKey, 0, m_encryptedKey.Length); 
                        }
                    } 
                } 

                return m_encryptedKey; 
            }
        }

        // 
        // Private methods.
        // 
 
        private void Reset (int version) {
            m_version = version; 
            m_recipientIdentifier = null;
            m_encryptionAlgorithm = null;
            m_encryptedKey = new byte[0];
        } 
    }
 
    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public sealed class KeyAgreeRecipientInfo : RecipientInfo {
        private CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO  m_encryptedKeyInfo; 
        private uint                                    m_originatorChoice;
        private int                                     m_version;
        private SubjectIdentifierOrKey                  m_originatorIdentifier;
        private byte[]                                  m_userKeyMaterial; 
        private AlgorithmIdentifier                     m_encryptionAlgorithm;
        private SubjectIdentifier                       m_recipientIdentifier; 
        private byte[]                                  m_encryptedKey; 
        private DateTime                                m_date;
        private CryptographicAttributeObject                  m_otherKeyAttribute; 
        private uint                                    m_subIndex;

        private KeyAgreeRecipientInfo () {}
 
        internal unsafe KeyAgreeRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO certIdRecipient, uint index, uint subIndex) : base(RecipientInfoType.KeyAgreement, RecipientSubType.CertIdKeyAgreement, pRecipientInfo, certIdRecipient, index) {
            IntPtr pEncryptedKeyInfo = Marshal.ReadIntPtr(new IntPtr((long) certIdRecipient.rgpRecipientEncryptedKeys + (long) (subIndex * Marshal.SizeOf(typeof(IntPtr))))); 
            CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO encryptedKeyInfo = (CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO) Marshal.PtrToStructure(pEncryptedKeyInfo, typeof(CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO)); 
            Reset(CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT, certIdRecipient.dwVersion, encryptedKeyInfo, subIndex);
        } 

        internal unsafe KeyAgreeRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO publicKeyRecipient, uint index, uint subIndex) : base(RecipientInfoType.KeyAgreement, RecipientSubType.PublicKeyAgreement, pRecipientInfo, publicKeyRecipient, index) {
            IntPtr pEncryptedKeyInfo = Marshal.ReadIntPtr(new IntPtr((long) publicKeyRecipient.rgpRecipientEncryptedKeys + (long) (subIndex * Marshal.SizeOf(typeof(IntPtr)))));
            CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO encryptedKeyInfo = (CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO) Marshal.PtrToStructure(pEncryptedKeyInfo, typeof(CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO)); 
            Reset(CAPI.CMSG_KEY_AGREE_ORIGINATOR_PUBLIC_KEY, publicKeyRecipient.dwVersion, encryptedKeyInfo, subIndex);
        } 
 
        public override int Version {
            get { 
                return m_version;
            }
        }
 
        public SubjectIdentifierOrKey OriginatorIdentifierOrKey {
            get { 
                if (m_originatorIdentifier == null) { 
                    if (m_originatorChoice == CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT) {
                        CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO) CmsgRecipientInfo; 
                        m_originatorIdentifier = new SubjectIdentifierOrKey(recipientInfo.OriginatorCertId);
                    }
                    else {
                        CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO) CmsgRecipientInfo; 
                        m_originatorIdentifier = new SubjectIdentifierOrKey(recipientInfo.OriginatorPublicKeyInfo);
                    } 
                } 

                return m_originatorIdentifier; 
            }
        }

        public override SubjectIdentifier RecipientIdentifier { 
            get {
                if (m_recipientIdentifier == null) 
                    m_recipientIdentifier = new SubjectIdentifier(m_encryptedKeyInfo.RecipientId); 

                return m_recipientIdentifier; 
            }
        }

        public DateTime Date { 
            get {
                if (m_date == DateTime.MinValue) { 
                    if (this.RecipientIdentifier.Type != SubjectIdentifierType.SubjectKeyIdentifier) 
                        throw new InvalidOperationException(SecurityResources.GetResourceString("Cryptography_Cms_Key_Agree_Date_Not_Available"));
 
                    long date = (((long)(uint) m_encryptedKeyInfo.Date.dwHighDateTime) << 32) | ((long)(uint) m_encryptedKeyInfo.Date.dwLowDateTime);
                    m_date = DateTime.FromFileTimeUtc(date);
                }
 
                return m_date;
            } 
        } 

        public CryptographicAttributeObject OtherKeyAttribute { 
            get {
                if (m_otherKeyAttribute == null) {
                    if (this.RecipientIdentifier.Type != SubjectIdentifierType.SubjectKeyIdentifier)
                        throw new InvalidOperationException(SecurityResources.GetResourceString("Cryptography_Cms_Key_Agree_Other_Key_Attribute_Not_Available")); 

                    if (m_encryptedKeyInfo.pOtherAttr != IntPtr.Zero) { 
                        CAPI.CRYPT_ATTRIBUTE_TYPE_VALUE otherKeyAttribute = (CAPI.CRYPT_ATTRIBUTE_TYPE_VALUE) Marshal.PtrToStructure(m_encryptedKeyInfo.pOtherAttr, typeof(CAPI.CRYPT_ATTRIBUTE_TYPE_VALUE)); 
                        m_otherKeyAttribute = new CryptographicAttributeObject(otherKeyAttribute);
                    } 
                }

                return m_otherKeyAttribute;
            } 
        }
 
        public override AlgorithmIdentifier KeyEncryptionAlgorithm { 
            get {
                if (m_encryptionAlgorithm == null) { 
                    if (m_originatorChoice == CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT) {
                        CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO) CmsgRecipientInfo;
                        m_encryptionAlgorithm = new AlgorithmIdentifier(recipientInfo.KeyEncryptionAlgorithm);
                    } 
                    else {
                        CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO) CmsgRecipientInfo; 
                        m_encryptionAlgorithm = new AlgorithmIdentifier(recipientInfo.KeyEncryptionAlgorithm); 
                    }
                } 

                return m_encryptionAlgorithm;
            }
        } 

        public override byte[] EncryptedKey { 
            get { 
                if (m_encryptedKey.Length == 0) {
                    if (m_encryptedKeyInfo.EncryptedKey.cbData > 0) { 
                        m_encryptedKey = new byte[m_encryptedKeyInfo.EncryptedKey.cbData];
                        Marshal.Copy(m_encryptedKeyInfo.EncryptedKey.pbData, m_encryptedKey, 0, m_encryptedKey.Length);
                    }
                } 

                return m_encryptedKey; 
            } 
        }
 
        //
        // Internal methods.
        //
 
        internal CAPI.CERT_ID RecipientId {
            get { 
                return m_encryptedKeyInfo.RecipientId; 
            }
        } 

        internal uint SubIndex {
            get {
                return m_subIndex; 
            }
        } 
 
        //
        // Private methods. 
        //

        private void Reset (uint originatorChoice, uint version, CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO encryptedKeyInfo, uint subIndex) {
            m_encryptedKeyInfo = encryptedKeyInfo; 
            m_originatorChoice = originatorChoice;
            m_version = (int) version; 
            m_originatorIdentifier = null; 
            m_userKeyMaterial = new byte[0];
            m_encryptionAlgorithm = null; 
            m_recipientIdentifier = null;
            m_encryptedKey = new byte[0];
            m_date = DateTime.MinValue;
            m_otherKeyAttribute = null; 
            m_subIndex = subIndex;
        } 
    } 

    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public sealed class RecipientInfoCollection : ICollection {
        private SafeCryptMsgHandle  m_safeCryptMsgHandle;
        private ArrayList           m_recipientInfos;
 
        internal RecipientInfoCollection () {
            m_safeCryptMsgHandle = SafeCryptMsgHandle.InvalidHandle; 
            m_recipientInfos = new ArrayList(); 
        }
 
        internal RecipientInfoCollection (RecipientInfo recipientInfo) {
            m_safeCryptMsgHandle = SafeCryptMsgHandle.InvalidHandle;
            m_recipientInfos = new ArrayList(1);
            m_recipientInfos.Add(recipientInfo); 
        }
 
        internal unsafe RecipientInfoCollection (SafeCryptMsgHandle safeCryptMsgHandle) { 
            bool cmsSupported = PkcsUtils.CmsSupported();
            uint dwRecipients = 0; 
            uint cbCount = (uint) Marshal.SizeOf(typeof(uint));

            // Use CMS if supported.
            if (cmsSupported) { 
                // CMS.
                if (!CAPI.CryptMsgGetParam(safeCryptMsgHandle, 
                                           CAPI.CMSG_CMS_RECIPIENT_COUNT_PARAM, 
                                           0,
                                           new IntPtr(&dwRecipients), 
                                           new IntPtr(&cbCount)))
                    throw new CryptographicException(Marshal.GetLastWin32Error());
            }
            else { 
                // PKCS7.
                if (!CAPI.CryptMsgGetParam(safeCryptMsgHandle, 
                                           CAPI.CMSG_RECIPIENT_COUNT_PARAM, 
                                           0,
                                           new IntPtr(&dwRecipients), 
                                           new IntPtr(&cbCount)))
                    throw new CryptographicException(Marshal.GetLastWin32Error());
            }
 
            m_recipientInfos = new ArrayList();
 
            for (uint index = 0; index < dwRecipients; index++) { 
                if (cmsSupported) {
                    uint cbCmsRecipientInfo; 
                    SafeLocalAllocHandle pbCmsRecipientInfo;

                    PkcsUtils.GetParam(safeCryptMsgHandle, CAPI.CMSG_CMS_RECIPIENT_INFO_PARAM, index, out pbCmsRecipientInfo, out cbCmsRecipientInfo);
                    CAPI.CMSG_CMS_RECIPIENT_INFO cmsRecipientInfo = (CAPI.CMSG_CMS_RECIPIENT_INFO) Marshal.PtrToStructure(pbCmsRecipientInfo.DangerousGetHandle(), typeof(CAPI.CMSG_CMS_RECIPIENT_INFO)); 

                    switch (cmsRecipientInfo.dwRecipientChoice) { 
                    case CAPI.CMSG_KEY_TRANS_RECIPIENT: 
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO));
                        m_recipientInfos.Add(new KeyTransRecipientInfo(pbCmsRecipientInfo, keyTrans, index)); 
                        break;
                    case CAPI.CMSG_KEY_AGREE_RECIPIENT:
                        CAPI.CMSG_KEY_AGREE_RECIPIENT_INFO keyAgree = (CAPI.CMSG_KEY_AGREE_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_AGREE_RECIPIENT_INFO));
                        switch (keyAgree.dwOriginatorChoice) { 
                        case CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT:
                            CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO certIdRecipient = (CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO)); 
                            for (uint cRecipient = 0; cRecipient < certIdRecipient.cRecipientEncryptedKeys; cRecipient++) { 
                                m_recipientInfos.Add(new KeyAgreeRecipientInfo(pbCmsRecipientInfo, certIdRecipient, index, cRecipient));
                            } 
                            break;
                        case CAPI.CMSG_KEY_AGREE_ORIGINATOR_PUBLIC_KEY:
                            CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO publicKeyRecipient = (CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO));
                            for (uint cRecipient = 0; cRecipient < publicKeyRecipient.cRecipientEncryptedKeys; cRecipient++) { 
                                m_recipientInfos.Add(new KeyAgreeRecipientInfo(pbCmsRecipientInfo, publicKeyRecipient, index, cRecipient));
                            } 
                            break; 
                        default:
                            throw new CryptographicException(SecurityResources.GetResourceString("Cryptography_Cms_Invalid_Originator_Identifier_Choice"), keyAgree.dwOriginatorChoice.ToString(CultureInfo.CurrentCulture)); 
                        }
                        break;
                    default:
                        throw new CryptographicException(CAPI.E_NOTIMPL); 
                    }
                } 
                else { 
                    uint cbCertInfo;
                    SafeLocalAllocHandle pbCertInfo; 

                    PkcsUtils.GetParam(safeCryptMsgHandle, CAPI.CMSG_RECIPIENT_INFO_PARAM, index, out pbCertInfo, out cbCertInfo);
                    CAPI.CERT_INFO certInfo = (CAPI.CERT_INFO) Marshal.PtrToStructure(pbCertInfo.DangerousGetHandle(), typeof(CAPI.CERT_INFO));
 
                    m_recipientInfos.Add(new KeyTransRecipientInfo(pbCertInfo, certInfo, index));
                } 
            } 

            m_safeCryptMsgHandle = safeCryptMsgHandle; 
        }

        public RecipientInfo this[int index] {
            get { 
                if (index < 0 || index >= m_recipientInfos.Count)
                    throw new ArgumentOutOfRangeException("index", SecurityResources.GetResourceString("ArgumentOutOfRange_Index")); 
                return (RecipientInfo) m_recipientInfos[index]; 
            }
        } 

        public int Count {
            get {
                return m_recipientInfos.Count; 
            }
        } 
 
        public RecipientInfoEnumerator GetEnumerator() {
            return new RecipientInfoEnumerator(this); 
        }

        /// 
        IEnumerator IEnumerable.GetEnumerator() { 
            return new RecipientInfoEnumerator(this);
        } 
 
        public void CopyTo(Array array, int index) {
            if (array == null) 
                throw new ArgumentNullException("array");
            if (array.Rank != 1)
                throw new ArgumentException(SecurityResources.GetResourceString("Arg_RankMultiDimNotSupported"));
            if (index < 0 || index >= array.Length) 
                throw new ArgumentOutOfRangeException("index", SecurityResources.GetResourceString("ArgumentOutOfRange_Index"));
            if (index + this.Count > array.Length) 
                throw new ArgumentException(SecurityResources.GetResourceString("Argument_InvalidOffLen")); 
            for (int i=0; i < this.Count; i++) {
                array.SetValue(this[i], index); 
                index++;
            }
        }
 
        public void CopyTo(RecipientInfo[] array, int index) {
            ((ICollection)this).CopyTo(array, index); 
        } 

        public bool IsSynchronized { 
            get {
                return false;
            }
        } 

        public Object SyncRoot { 
            get { 
                return this;
            } 
        }
    }

    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public sealed class RecipientInfoEnumerator : IEnumerator {
        private RecipientInfoCollection m_recipientInfos; 
        private int m_current; 

        private RecipientInfoEnumerator() {} 

        internal RecipientInfoEnumerator(RecipientInfoCollection RecipientInfos) {
            m_recipientInfos = RecipientInfos;
            m_current = -1; 
        }
 
        public RecipientInfo Current { 
            get {
                return m_recipientInfos[m_current]; 
            }
        }

        ///  
        Object IEnumerator.Current {
            get { 
                return (Object) m_recipientInfos[m_current]; 
            }
        } 

        public bool MoveNext() {
            if (m_current == ((int) m_recipientInfos.Count - 1)) {
                return false; 
            }
            m_current++; 
            return true; 
        }
 
        public void Reset() {
            m_current = -1;
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

// 
// RecipientInfo.cs 
//
 
namespace System.Security.Cryptography.Pkcs
{
    using System.Collections;
    using System.Runtime.InteropServices; 
    using System.Security.Cryptography;
    using System.Security.Cryptography.X509Certificates; 
    using System.Security.Cryptography.Xml; 
    using System.Globalization;
 
    public enum RecipientInfoType {
        Unknown      = 0,
        KeyTransport = 1,   // Must be the same as CAPI.CMSG_KEY_TRANS_RECIPIENT (1)
        KeyAgreement = 2,   // Must be the same as CAPI.CMSG_KEY_AGREE_RECIPIENT (2) 
    }
 
    internal enum RecipientSubType { 
        Unknown            = 0,
        Pkcs7KeyTransport  = 1, 
        CmsKeyTransport    = 2,
        CertIdKeyAgreement = 3,
        PublicKeyAgreement = 4,
    } 

    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public abstract class RecipientInfo { 
        private RecipientInfoType    m_recipentInfoType;
        private RecipientSubType     m_recipientSubType; 
        private SafeLocalAllocHandle m_pCmsgRecipientInfo;
        private Object               m_cmsgRecipientInfo;
        private uint                 m_index;
 
        internal RecipientInfo () {}
 
        internal RecipientInfo (RecipientInfoType recipientInfoType, RecipientSubType recipientSubType, SafeLocalAllocHandle pCmsgRecipientInfo, Object cmsgRecipientInfo, uint index) { 
            if (recipientInfoType < RecipientInfoType.Unknown || recipientInfoType > RecipientInfoType.KeyAgreement)
                recipientInfoType = RecipientInfoType.Unknown; 

            if (recipientSubType < RecipientSubType.Unknown || recipientSubType > RecipientSubType.PublicKeyAgreement)
                recipientSubType = RecipientSubType.Unknown;
 
            m_recipentInfoType = recipientInfoType;
            m_recipientSubType = recipientSubType; 
            m_pCmsgRecipientInfo = pCmsgRecipientInfo; 
            m_cmsgRecipientInfo = cmsgRecipientInfo;
            m_index = index; 
        }

        public RecipientInfoType Type {
            get { 
                return m_recipentInfoType;
            } 
        } 

        public abstract int Version { get; } 

        public abstract SubjectIdentifier RecipientIdentifier { get; }

        public abstract AlgorithmIdentifier KeyEncryptionAlgorithm { get; } 

        public abstract byte[] EncryptedKey { get; } 
 
        //
        // Internal methods. 
        //

        internal RecipientSubType SubType {
            get { 
                return m_recipientSubType;
            } 
        } 

        internal SafeLocalAllocHandle pCmsgRecipientInfo { 
            get {
                return m_pCmsgRecipientInfo;
            }
        } 

        internal Object CmsgRecipientInfo { 
            get { 
                return m_cmsgRecipientInfo;
            } 
        }

        internal uint Index {
            get { 
                return m_index;
            } 
        } 
    }
 
    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)]
    public sealed class KeyTransRecipientInfo : RecipientInfo {
        private int                     m_version;
        private SubjectIdentifier       m_recipientIdentifier; 
        private AlgorithmIdentifier     m_encryptionAlgorithm;
        private byte[]                  m_encryptedKey; 
 
        private KeyTransRecipientInfo () {}
 
        internal unsafe KeyTransRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CERT_INFO certInfo, uint index) : base(RecipientInfoType.KeyTransport, RecipientSubType.Pkcs7KeyTransport, pRecipientInfo, certInfo, index) {
            // If serial number is 0, then it is the special SKI encoding.
            int version = 2;
            byte * pb = (byte *) certInfo.SerialNumber.pbData; 
            for (int i = 0; i < certInfo.SerialNumber.cbData; i++) {
                if (*pb++ != (byte) 0) { 
                    version = 0; 
                    break;
                } 
            }

            Reset(version);
        } 

        internal unsafe KeyTransRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans, uint index) : base(RecipientInfoType.KeyTransport, RecipientSubType.CmsKeyTransport, pRecipientInfo, keyTrans, index) { 
            Reset((int) keyTrans.dwVersion); 
        }
 
        public override int Version {
            get {
                return m_version;
            } 
        }
 
        public override SubjectIdentifier RecipientIdentifier { 
            get {
                if (m_recipientIdentifier == null) { 
                    if (this.SubType == RecipientSubType.CmsKeyTransport) {
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) CmsgRecipientInfo;
                        m_recipientIdentifier = new SubjectIdentifier(keyTrans.RecipientId);
                    } 
                    else {
                        CAPI.CERT_INFO certInfo = (CAPI.CERT_INFO) CmsgRecipientInfo; 
                        m_recipientIdentifier = new SubjectIdentifier(certInfo); 
                    }
                } 

                return m_recipientIdentifier;
            }
        } 

        public override AlgorithmIdentifier KeyEncryptionAlgorithm { 
            get { 
                if (m_encryptionAlgorithm == null) {
                    if (this.SubType == RecipientSubType.CmsKeyTransport) { 
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) CmsgRecipientInfo;
                        m_encryptionAlgorithm = new AlgorithmIdentifier(keyTrans.KeyEncryptionAlgorithm);
                    }
                    else { 
                        CAPI.CERT_INFO certInfo = (CAPI.CERT_INFO) CmsgRecipientInfo;
                        m_encryptionAlgorithm = new AlgorithmIdentifier(certInfo.SignatureAlgorithm); 
                    } 
                }
 
                return m_encryptionAlgorithm;
            }
        }
 
        public override byte[] EncryptedKey {
            get { 
                if (m_encryptedKey.Length == 0) { 
                    // CAPI does not provide a way to retrieve encrypted key for PKCS 7 message.
                    if (this.SubType == RecipientSubType.CmsKeyTransport) { 
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) CmsgRecipientInfo;
                        if (keyTrans.EncryptedKey.cbData > 0) {
                            m_encryptedKey = new byte[keyTrans.EncryptedKey.cbData];
                            Marshal.Copy(keyTrans.EncryptedKey.pbData, m_encryptedKey, 0, m_encryptedKey.Length); 
                        }
                    } 
                } 

                return m_encryptedKey; 
            }
        }

        // 
        // Private methods.
        // 
 
        private void Reset (int version) {
            m_version = version; 
            m_recipientIdentifier = null;
            m_encryptionAlgorithm = null;
            m_encryptedKey = new byte[0];
        } 
    }
 
    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public sealed class KeyAgreeRecipientInfo : RecipientInfo {
        private CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO  m_encryptedKeyInfo; 
        private uint                                    m_originatorChoice;
        private int                                     m_version;
        private SubjectIdentifierOrKey                  m_originatorIdentifier;
        private byte[]                                  m_userKeyMaterial; 
        private AlgorithmIdentifier                     m_encryptionAlgorithm;
        private SubjectIdentifier                       m_recipientIdentifier; 
        private byte[]                                  m_encryptedKey; 
        private DateTime                                m_date;
        private CryptographicAttributeObject                  m_otherKeyAttribute; 
        private uint                                    m_subIndex;

        private KeyAgreeRecipientInfo () {}
 
        internal unsafe KeyAgreeRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO certIdRecipient, uint index, uint subIndex) : base(RecipientInfoType.KeyAgreement, RecipientSubType.CertIdKeyAgreement, pRecipientInfo, certIdRecipient, index) {
            IntPtr pEncryptedKeyInfo = Marshal.ReadIntPtr(new IntPtr((long) certIdRecipient.rgpRecipientEncryptedKeys + (long) (subIndex * Marshal.SizeOf(typeof(IntPtr))))); 
            CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO encryptedKeyInfo = (CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO) Marshal.PtrToStructure(pEncryptedKeyInfo, typeof(CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO)); 
            Reset(CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT, certIdRecipient.dwVersion, encryptedKeyInfo, subIndex);
        } 

        internal unsafe KeyAgreeRecipientInfo (SafeLocalAllocHandle pRecipientInfo, CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO publicKeyRecipient, uint index, uint subIndex) : base(RecipientInfoType.KeyAgreement, RecipientSubType.PublicKeyAgreement, pRecipientInfo, publicKeyRecipient, index) {
            IntPtr pEncryptedKeyInfo = Marshal.ReadIntPtr(new IntPtr((long) publicKeyRecipient.rgpRecipientEncryptedKeys + (long) (subIndex * Marshal.SizeOf(typeof(IntPtr)))));
            CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO encryptedKeyInfo = (CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO) Marshal.PtrToStructure(pEncryptedKeyInfo, typeof(CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO)); 
            Reset(CAPI.CMSG_KEY_AGREE_ORIGINATOR_PUBLIC_KEY, publicKeyRecipient.dwVersion, encryptedKeyInfo, subIndex);
        } 
 
        public override int Version {
            get { 
                return m_version;
            }
        }
 
        public SubjectIdentifierOrKey OriginatorIdentifierOrKey {
            get { 
                if (m_originatorIdentifier == null) { 
                    if (m_originatorChoice == CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT) {
                        CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO) CmsgRecipientInfo; 
                        m_originatorIdentifier = new SubjectIdentifierOrKey(recipientInfo.OriginatorCertId);
                    }
                    else {
                        CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO) CmsgRecipientInfo; 
                        m_originatorIdentifier = new SubjectIdentifierOrKey(recipientInfo.OriginatorPublicKeyInfo);
                    } 
                } 

                return m_originatorIdentifier; 
            }
        }

        public override SubjectIdentifier RecipientIdentifier { 
            get {
                if (m_recipientIdentifier == null) 
                    m_recipientIdentifier = new SubjectIdentifier(m_encryptedKeyInfo.RecipientId); 

                return m_recipientIdentifier; 
            }
        }

        public DateTime Date { 
            get {
                if (m_date == DateTime.MinValue) { 
                    if (this.RecipientIdentifier.Type != SubjectIdentifierType.SubjectKeyIdentifier) 
                        throw new InvalidOperationException(SecurityResources.GetResourceString("Cryptography_Cms_Key_Agree_Date_Not_Available"));
 
                    long date = (((long)(uint) m_encryptedKeyInfo.Date.dwHighDateTime) << 32) | ((long)(uint) m_encryptedKeyInfo.Date.dwLowDateTime);
                    m_date = DateTime.FromFileTimeUtc(date);
                }
 
                return m_date;
            } 
        } 

        public CryptographicAttributeObject OtherKeyAttribute { 
            get {
                if (m_otherKeyAttribute == null) {
                    if (this.RecipientIdentifier.Type != SubjectIdentifierType.SubjectKeyIdentifier)
                        throw new InvalidOperationException(SecurityResources.GetResourceString("Cryptography_Cms_Key_Agree_Other_Key_Attribute_Not_Available")); 

                    if (m_encryptedKeyInfo.pOtherAttr != IntPtr.Zero) { 
                        CAPI.CRYPT_ATTRIBUTE_TYPE_VALUE otherKeyAttribute = (CAPI.CRYPT_ATTRIBUTE_TYPE_VALUE) Marshal.PtrToStructure(m_encryptedKeyInfo.pOtherAttr, typeof(CAPI.CRYPT_ATTRIBUTE_TYPE_VALUE)); 
                        m_otherKeyAttribute = new CryptographicAttributeObject(otherKeyAttribute);
                    } 
                }

                return m_otherKeyAttribute;
            } 
        }
 
        public override AlgorithmIdentifier KeyEncryptionAlgorithm { 
            get {
                if (m_encryptionAlgorithm == null) { 
                    if (m_originatorChoice == CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT) {
                        CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO) CmsgRecipientInfo;
                        m_encryptionAlgorithm = new AlgorithmIdentifier(recipientInfo.KeyEncryptionAlgorithm);
                    } 
                    else {
                        CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO recipientInfo = (CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO) CmsgRecipientInfo; 
                        m_encryptionAlgorithm = new AlgorithmIdentifier(recipientInfo.KeyEncryptionAlgorithm); 
                    }
                } 

                return m_encryptionAlgorithm;
            }
        } 

        public override byte[] EncryptedKey { 
            get { 
                if (m_encryptedKey.Length == 0) {
                    if (m_encryptedKeyInfo.EncryptedKey.cbData > 0) { 
                        m_encryptedKey = new byte[m_encryptedKeyInfo.EncryptedKey.cbData];
                        Marshal.Copy(m_encryptedKeyInfo.EncryptedKey.pbData, m_encryptedKey, 0, m_encryptedKey.Length);
                    }
                } 

                return m_encryptedKey; 
            } 
        }
 
        //
        // Internal methods.
        //
 
        internal CAPI.CERT_ID RecipientId {
            get { 
                return m_encryptedKeyInfo.RecipientId; 
            }
        } 

        internal uint SubIndex {
            get {
                return m_subIndex; 
            }
        } 
 
        //
        // Private methods. 
        //

        private void Reset (uint originatorChoice, uint version, CAPI.CMSG_RECIPIENT_ENCRYPTED_KEY_INFO encryptedKeyInfo, uint subIndex) {
            m_encryptedKeyInfo = encryptedKeyInfo; 
            m_originatorChoice = originatorChoice;
            m_version = (int) version; 
            m_originatorIdentifier = null; 
            m_userKeyMaterial = new byte[0];
            m_encryptionAlgorithm = null; 
            m_recipientIdentifier = null;
            m_encryptedKey = new byte[0];
            m_date = DateTime.MinValue;
            m_otherKeyAttribute = null; 
            m_subIndex = subIndex;
        } 
    } 

    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public sealed class RecipientInfoCollection : ICollection {
        private SafeCryptMsgHandle  m_safeCryptMsgHandle;
        private ArrayList           m_recipientInfos;
 
        internal RecipientInfoCollection () {
            m_safeCryptMsgHandle = SafeCryptMsgHandle.InvalidHandle; 
            m_recipientInfos = new ArrayList(); 
        }
 
        internal RecipientInfoCollection (RecipientInfo recipientInfo) {
            m_safeCryptMsgHandle = SafeCryptMsgHandle.InvalidHandle;
            m_recipientInfos = new ArrayList(1);
            m_recipientInfos.Add(recipientInfo); 
        }
 
        internal unsafe RecipientInfoCollection (SafeCryptMsgHandle safeCryptMsgHandle) { 
            bool cmsSupported = PkcsUtils.CmsSupported();
            uint dwRecipients = 0; 
            uint cbCount = (uint) Marshal.SizeOf(typeof(uint));

            // Use CMS if supported.
            if (cmsSupported) { 
                // CMS.
                if (!CAPI.CryptMsgGetParam(safeCryptMsgHandle, 
                                           CAPI.CMSG_CMS_RECIPIENT_COUNT_PARAM, 
                                           0,
                                           new IntPtr(&dwRecipients), 
                                           new IntPtr(&cbCount)))
                    throw new CryptographicException(Marshal.GetLastWin32Error());
            }
            else { 
                // PKCS7.
                if (!CAPI.CryptMsgGetParam(safeCryptMsgHandle, 
                                           CAPI.CMSG_RECIPIENT_COUNT_PARAM, 
                                           0,
                                           new IntPtr(&dwRecipients), 
                                           new IntPtr(&cbCount)))
                    throw new CryptographicException(Marshal.GetLastWin32Error());
            }
 
            m_recipientInfos = new ArrayList();
 
            for (uint index = 0; index < dwRecipients; index++) { 
                if (cmsSupported) {
                    uint cbCmsRecipientInfo; 
                    SafeLocalAllocHandle pbCmsRecipientInfo;

                    PkcsUtils.GetParam(safeCryptMsgHandle, CAPI.CMSG_CMS_RECIPIENT_INFO_PARAM, index, out pbCmsRecipientInfo, out cbCmsRecipientInfo);
                    CAPI.CMSG_CMS_RECIPIENT_INFO cmsRecipientInfo = (CAPI.CMSG_CMS_RECIPIENT_INFO) Marshal.PtrToStructure(pbCmsRecipientInfo.DangerousGetHandle(), typeof(CAPI.CMSG_CMS_RECIPIENT_INFO)); 

                    switch (cmsRecipientInfo.dwRecipientChoice) { 
                    case CAPI.CMSG_KEY_TRANS_RECIPIENT: 
                        CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO keyTrans = (CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_TRANS_RECIPIENT_INFO));
                        m_recipientInfos.Add(new KeyTransRecipientInfo(pbCmsRecipientInfo, keyTrans, index)); 
                        break;
                    case CAPI.CMSG_KEY_AGREE_RECIPIENT:
                        CAPI.CMSG_KEY_AGREE_RECIPIENT_INFO keyAgree = (CAPI.CMSG_KEY_AGREE_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_AGREE_RECIPIENT_INFO));
                        switch (keyAgree.dwOriginatorChoice) { 
                        case CAPI.CMSG_KEY_AGREE_ORIGINATOR_CERT:
                            CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO certIdRecipient = (CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_AGREE_CERT_ID_RECIPIENT_INFO)); 
                            for (uint cRecipient = 0; cRecipient < certIdRecipient.cRecipientEncryptedKeys; cRecipient++) { 
                                m_recipientInfos.Add(new KeyAgreeRecipientInfo(pbCmsRecipientInfo, certIdRecipient, index, cRecipient));
                            } 
                            break;
                        case CAPI.CMSG_KEY_AGREE_ORIGINATOR_PUBLIC_KEY:
                            CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO publicKeyRecipient = (CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO) Marshal.PtrToStructure(cmsRecipientInfo.pRecipientInfo, typeof(CAPI.CMSG_KEY_AGREE_PUBLIC_KEY_RECIPIENT_INFO));
                            for (uint cRecipient = 0; cRecipient < publicKeyRecipient.cRecipientEncryptedKeys; cRecipient++) { 
                                m_recipientInfos.Add(new KeyAgreeRecipientInfo(pbCmsRecipientInfo, publicKeyRecipient, index, cRecipient));
                            } 
                            break; 
                        default:
                            throw new CryptographicException(SecurityResources.GetResourceString("Cryptography_Cms_Invalid_Originator_Identifier_Choice"), keyAgree.dwOriginatorChoice.ToString(CultureInfo.CurrentCulture)); 
                        }
                        break;
                    default:
                        throw new CryptographicException(CAPI.E_NOTIMPL); 
                    }
                } 
                else { 
                    uint cbCertInfo;
                    SafeLocalAllocHandle pbCertInfo; 

                    PkcsUtils.GetParam(safeCryptMsgHandle, CAPI.CMSG_RECIPIENT_INFO_PARAM, index, out pbCertInfo, out cbCertInfo);
                    CAPI.CERT_INFO certInfo = (CAPI.CERT_INFO) Marshal.PtrToStructure(pbCertInfo.DangerousGetHandle(), typeof(CAPI.CERT_INFO));
 
                    m_recipientInfos.Add(new KeyTransRecipientInfo(pbCertInfo, certInfo, index));
                } 
            } 

            m_safeCryptMsgHandle = safeCryptMsgHandle; 
        }

        public RecipientInfo this[int index] {
            get { 
                if (index < 0 || index >= m_recipientInfos.Count)
                    throw new ArgumentOutOfRangeException("index", SecurityResources.GetResourceString("ArgumentOutOfRange_Index")); 
                return (RecipientInfo) m_recipientInfos[index]; 
            }
        } 

        public int Count {
            get {
                return m_recipientInfos.Count; 
            }
        } 
 
        public RecipientInfoEnumerator GetEnumerator() {
            return new RecipientInfoEnumerator(this); 
        }

        /// 
        IEnumerator IEnumerable.GetEnumerator() { 
            return new RecipientInfoEnumerator(this);
        } 
 
        public void CopyTo(Array array, int index) {
            if (array == null) 
                throw new ArgumentNullException("array");
            if (array.Rank != 1)
                throw new ArgumentException(SecurityResources.GetResourceString("Arg_RankMultiDimNotSupported"));
            if (index < 0 || index >= array.Length) 
                throw new ArgumentOutOfRangeException("index", SecurityResources.GetResourceString("ArgumentOutOfRange_Index"));
            if (index + this.Count > array.Length) 
                throw new ArgumentException(SecurityResources.GetResourceString("Argument_InvalidOffLen")); 
            for (int i=0; i < this.Count; i++) {
                array.SetValue(this[i], index); 
                index++;
            }
        }
 
        public void CopyTo(RecipientInfo[] array, int index) {
            ((ICollection)this).CopyTo(array, index); 
        } 

        public bool IsSynchronized { 
            get {
                return false;
            }
        } 

        public Object SyncRoot { 
            get { 
                return this;
            } 
        }
    }

    [System.Security.Permissions.HostProtection(MayLeakOnAbort = true)] 
    public sealed class RecipientInfoEnumerator : IEnumerator {
        private RecipientInfoCollection m_recipientInfos; 
        private int m_current; 

        private RecipientInfoEnumerator() {} 

        internal RecipientInfoEnumerator(RecipientInfoCollection RecipientInfos) {
            m_recipientInfos = RecipientInfos;
            m_current = -1; 
        }
 
        public RecipientInfo Current { 
            get {
                return m_recipientInfos[m_current]; 
            }
        }

        ///  
        Object IEnumerator.Current {
            get { 
                return (Object) m_recipientInfos[m_current]; 
            }
        } 

        public bool MoveNext() {
            if (m_current == ((int) m_recipientInfos.Count - 1)) {
                return false; 
            }
            m_current++; 
            return true; 
        }
 
        public void Reset() {
            m_current = -1;
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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