X509AsymmetricSecurityKey.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WCF / IdentityModel / System / IdentityModel / Tokens / X509AsymmetricSecurityKey.cs / 1305376 / X509AsymmetricSecurityKey.cs

                             
//------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------
 
namespace System.IdentityModel.Tokens
{ 
    using System.Security.Cryptography; 
    using System.Security.Cryptography.X509Certificates;
    using System.Security.Cryptography.Xml; 

    public class X509AsymmetricSecurityKey : AsymmetricSecurityKey
    {
        X509Certificate2 certificate; 
        AsymmetricAlgorithm privateKey;
        bool privateKeyAvailabilityDetermined; 
        PublicKey publicKey; 

        object thisLock = new Object(); 

        public X509AsymmetricSecurityKey( X509Certificate2 certificate )
        {
            if ( certificate == null ) 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull( "certificate" );
 
            this.certificate = certificate; 
        }
 
        public override int KeySize
        {
            get { return this.PublicKey.Key.KeySize; }
        } 

        AsymmetricAlgorithm PrivateKey 
        { 
            get
            { 
                if ( !this.privateKeyAvailabilityDetermined )
                {
                    lock ( ThisLock )
                    { 
                        if ( !this.privateKeyAvailabilityDetermined )
                        { 
                            this.privateKey = this.certificate.PrivateKey; 
                            this.privateKeyAvailabilityDetermined = true;
                        } 
                    }
                }
                return this.privateKey;
            } 
        }
 
        PublicKey PublicKey 
        {
            get 
            {
                if ( this.publicKey == null )
                {
                    lock ( ThisLock ) 
                    {
                        if ( this.publicKey == null ) 
                        { 
                            this.publicKey = this.certificate.PublicKey;
                        } 
                    }
                }
                return this.publicKey;
            } 
        }
 
        Object ThisLock 
        {
            get 
            {
                return thisLock;
            }
        } 

        public override byte[] DecryptKey( string algorithm, byte[] keyData ) 
        { 
            // We can decrypt key only if we have the private key in the certificate.
            if ( this.PrivateKey == null ) 
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.MissingPrivateKey ) ) );
            }
 
            RSA rsa = this.PrivateKey as RSA;
            if ( rsa == null ) 
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotRSA ) ) );
            } 

            // Support exchange keySpec, AT_EXCHANGE ?
            if ( rsa.KeyExchangeAlgorithm == null )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyExchangeNotSupported ) ) );
            } 
 
            switch ( algorithm )
            { 
            case EncryptedXml.XmlEncRSA15Url:
                return EncryptedXml.DecryptKey( keyData, rsa, false );

            case EncryptedXml.XmlEncRSAOAEPUrl: 
                return EncryptedXml.DecryptKey( keyData, rsa, true );
 
            default: 
                if ( IsSupportedAlgorithm( algorithm ) )
                    return EncryptedXml.DecryptKey( keyData, rsa, true ); 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
            }
        } 

        public override byte[] EncryptKey( string algorithm, byte[] keyData ) 
        { 
            // Ensure that we have an RSA algorithm object
            RSA rsa = this.PublicKey.Key as RSA; 
            if ( rsa == null )
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PublicKeyNotRSA ) ) );
            } 

            switch ( algorithm ) 
            { 
            case EncryptedXml.XmlEncRSA15Url:
                return EncryptedXml.EncryptKey( keyData, rsa, false ); 

            case EncryptedXml.XmlEncRSAOAEPUrl:
                return EncryptedXml.EncryptKey( keyData, rsa, true );
 
            default:
                if ( IsSupportedAlgorithm( algorithm ) ) 
                    return EncryptedXml.EncryptKey( keyData, rsa, true ); 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) ); 
            }
        }

        public override AsymmetricAlgorithm GetAsymmetricAlgorithm( string algorithm, bool privateKey ) 
        {
            if ( privateKey ) 
            { 
                if ( this.PrivateKey == null )
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.MissingPrivateKey ) ) );
                }

                if ( String.IsNullOrEmpty( algorithm ) ) 
                {
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) ); 
                } 

                switch ( algorithm ) 
                {
                case SignedXml.XmlDsigDSAUrl:
                    if ( ( this.PrivateKey as DSA ) != null )
                    { 
                        return ( this.PrivateKey as DSA );
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPrivateKeyMisMatch ) ) ); 

                case SignedXml.XmlDsigRSASHA1Url: 
                case SecurityAlgorithms.RsaSha256Signature:
                case EncryptedXml.XmlEncRSA15Url:
                case EncryptedXml.XmlEncRSAOAEPUrl:
                    if ( ( this.PrivateKey as RSA ) != null ) 
                    {
                        return ( this.PrivateKey as RSA ); 
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPrivateKeyMisMatch ) ) );
                default: 
                    if ( IsSupportedAlgorithm( algorithm ) )
                        return this.PrivateKey;
                    else
                        throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) ); 
                }
            } 
            else 
            {
                switch ( algorithm ) 
                {
                case SignedXml.XmlDsigDSAUrl:
                    if ( ( this.PublicKey.Key as DSA ) != null )
                    { 
                        return ( this.PublicKey.Key as DSA );
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPublicKeyMisMatch ) ) ); 
                case SignedXml.XmlDsigRSASHA1Url:
                case SecurityAlgorithms.RsaSha256Signature: 
                case EncryptedXml.XmlEncRSA15Url:
                case EncryptedXml.XmlEncRSAOAEPUrl:
                    if ( ( this.PublicKey.Key as RSA ) != null )
                    { 
                        return ( this.PublicKey.Key as RSA );
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPublicKeyMisMatch ) ) ); 
                default:
 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
                }
            }
        } 

        public override HashAlgorithm GetHashAlgorithmForSignature( string algorithm ) 
        { 
            if ( String.IsNullOrEmpty( algorithm ) )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) );
            }

            object algorithmObject = CryptoHelper.GetAlgorithmFromConfig( algorithm ); 

            if ( algorithmObject != null ) 
            { 
                SignatureDescription description = algorithmObject as SignatureDescription;
                if ( description != null ) 
                    return description.CreateDigest();

                HashAlgorithm hashAlgorithm = algorithmObject as HashAlgorithm;
                if ( hashAlgorithm != null ) 
                    return hashAlgorithm;
 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new CryptographicException( SR.GetString( SR.UnsupportedAlgorithmForCryptoOperation, 
                        algorithm, "CreateDigest" ) ) );
            } 

            switch ( algorithm )
            {
            case SignedXml.XmlDsigDSAUrl: 
            case SignedXml.XmlDsigRSASHA1Url:
                return CryptoHelper.NewSha1HashAlgorithm(); 
            case SecurityAlgorithms.RsaSha256Signature: 
                return CryptoHelper.NewSha256HashAlgorithm();
            default: 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
            }
        }
 
        public override AsymmetricSignatureDeformatter GetSignatureDeformatter( string algorithm )
        { 
 
            // We support one of the two algoritms, but not both.
            //     XmlDsigDSAUrl = "http://www.w3.org/2000/09/xmldsig#dsa-sha1"; 
            //     XmlDsigRSASHA1Url = "http://www.w3.org/2000/09/xmldsig#rsa-sha1";

            if ( String.IsNullOrEmpty( algorithm ) )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) );
            } 
 
            object algorithmObject = CryptoHelper.GetAlgorithmFromConfig( algorithm );
            if ( algorithmObject != null ) 
            {
                SignatureDescription description = algorithmObject as SignatureDescription;
                if ( description != null )
                    return description.CreateDeformatter( this.PublicKey.Key ); 

                try 
                { 
                    AsymmetricSignatureDeformatter asymmetricSignatureDeformatter = algorithmObject as AsymmetricSignatureDeformatter;
                    if ( asymmetricSignatureDeformatter != null ) 
                    {
                        asymmetricSignatureDeformatter.SetKey( this.PublicKey.Key );
                        return asymmetricSignatureDeformatter;
                    } 
                }
                catch ( InvalidCastException e ) 
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPublicKeyMisMatch ), e ) );
                } 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new CryptographicException( SR.GetString( SR.UnsupportedAlgorithmForCryptoOperation,
                       algorithm, "GetSignatureDeformatter" ) ) );
            } 

            switch ( algorithm ) 
            { 
            case SignedXml.XmlDsigDSAUrl:
 
                // Ensure that we have a DSA algorithm object.
                DSA dsa = ( this.PublicKey.Key as DSA );
                if ( dsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PublicKeyNotDSA ) ) ); 
                return new DSASignatureDeformatter( dsa );
 
            case SignedXml.XmlDsigRSASHA1Url: 
            case SecurityAlgorithms.RsaSha256Signature:
                // Ensure that we have an RSA algorithm object. 
                RSA rsa = ( this.PublicKey.Key as RSA );
                if ( rsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PublicKeyNotRSA ) ) );
                return new RSAPKCS1SignatureDeformatter( rsa ); 

            default: 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) ); 
            }
        } 

        public override AsymmetricSignatureFormatter GetSignatureFormatter( string algorithm )
        {
            // One can sign only if the private key is present. 
            if ( this.PrivateKey == null )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.MissingPrivateKey ) ) ); 
            }
 
            if ( String.IsNullOrEmpty( algorithm ) )
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) );
            } 
            // We support one of the two algoritms, but not both.
            //     XmlDsigDSAUrl = "http://www.w3.org/2000/09/xmldsig#dsa-sha1"; 
            //     XmlDsigRSASHA1Url = "http://www.w3.org/2000/09/xmldsig#rsa-sha1"; 
            object algorithmObject = CryptoHelper.GetAlgorithmFromConfig( algorithm );
            if ( algorithmObject != null ) 
            {
                SignatureDescription description = algorithmObject as SignatureDescription;
                if ( description != null )
                    return description.CreateFormatter( this.PrivateKey ); 

                try 
                { 
                    AsymmetricSignatureFormatter asymmetricSignatureFormatter = algorithmObject as AsymmetricSignatureFormatter;
                    if ( asymmetricSignatureFormatter != null ) 
                    {
                        asymmetricSignatureFormatter.SetKey( this.PrivateKey );
                        return asymmetricSignatureFormatter;
                    } 
                }
                catch ( InvalidCastException e ) 
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPrivateKeyMisMatch ), e ) );
                } 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new CryptographicException( SR.GetString( SR.UnsupportedAlgorithmForCryptoOperation,
                       algorithm, "GetSignatureFormatter" ) ) );
            } 

            switch ( algorithm ) 
            { 
            case SignedXml.XmlDsigDSAUrl:
 
                // Ensure that we have a DSA algorithm object.
                DSA dsa = ( this.PrivateKey as DSA );
                if ( dsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotDSA ) ) ); 
                return new DSASignatureFormatter( dsa );
 
            case SignedXml.XmlDsigRSASHA1Url: 
                // Ensure that we have an RSA algorithm object.
                RSA rsa = ( this.PrivateKey as RSA ); 
                if ( rsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotRSA ) ) );
                return new RSAPKCS1SignatureFormatter( rsa );
 
            case SecurityAlgorithms.RsaSha256Signature:
                // Ensure that we have an RSA algorithm object. 
                RSACryptoServiceProvider rsa_prov_full = ( this.PrivateKey as RSACryptoServiceProvider ); 
                if ( rsa_prov_full == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotRSA ) ) ); 
                CspParameters csp = new CspParameters();
                csp.ProviderType = 24;
                csp.KeyContainerName = rsa_prov_full.CspKeyContainerInfo.KeyContainerName;
                csp.KeyNumber = (int)rsa_prov_full.CspKeyContainerInfo.KeyNumber; 
                if ( rsa_prov_full.CspKeyContainerInfo.MachineKeyStore )
                    csp.Flags = CspProviderFlags.UseMachineKeyStore; 
                return new RSAPKCS1SignatureFormatter( new RSACryptoServiceProvider( csp ) ); 

            default: 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
            }

        } 

        public override bool HasPrivateKey() 
        { 
            return ( this.PrivateKey != null );
        } 

        public override bool IsAsymmetricAlgorithm( string algorithm )
        {
            if ( String.IsNullOrEmpty( algorithm ) ) 
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) ); 
            } 

            return ( CryptoHelper.IsAsymmetricAlgorithm( algorithm ) ); 
        }

        public override bool IsSupportedAlgorithm( string algorithm )
        { 
            if ( String.IsNullOrEmpty( algorithm ) )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) ); 
            }
 
            object algorithmObject = null;
            try
            {
                algorithmObject =  CryptoHelper.GetAlgorithmFromConfig( algorithm ); 
            }
            catch (InvalidOperationException) 
            { 
                algorithm = null;
            } 

            if ( algorithmObject != null )
            {
                SignatureDescription signatureDescription = algorithmObject as SignatureDescription; 
                if ( signatureDescription != null )
                    return true; 
                AsymmetricAlgorithm asymmetricAlgorithm = algorithmObject as AsymmetricAlgorithm; 
                if ( asymmetricAlgorithm != null )
                    return true; 
                return false;
            }

            switch ( algorithm ) 
            {
            case SignedXml.XmlDsigDSAUrl: 
                return ( this.PublicKey.Key is DSA ); 

            case SignedXml.XmlDsigRSASHA1Url: 
            case SecurityAlgorithms.RsaSha256Signature:
            case EncryptedXml.XmlEncRSA15Url:
            case EncryptedXml.XmlEncRSAOAEPUrl:
                return ( this.PublicKey.Key is RSA ); 
            default:
                return false; 
            } 
        }
 
        public override bool IsSymmetricAlgorithm( string algorithm )
        {
            return CryptoHelper.IsSymmetricAlgorithm( algorithm );
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
 
//------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------
 
namespace System.IdentityModel.Tokens
{ 
    using System.Security.Cryptography; 
    using System.Security.Cryptography.X509Certificates;
    using System.Security.Cryptography.Xml; 

    public class X509AsymmetricSecurityKey : AsymmetricSecurityKey
    {
        X509Certificate2 certificate; 
        AsymmetricAlgorithm privateKey;
        bool privateKeyAvailabilityDetermined; 
        PublicKey publicKey; 

        object thisLock = new Object(); 

        public X509AsymmetricSecurityKey( X509Certificate2 certificate )
        {
            if ( certificate == null ) 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull( "certificate" );
 
            this.certificate = certificate; 
        }
 
        public override int KeySize
        {
            get { return this.PublicKey.Key.KeySize; }
        } 

        AsymmetricAlgorithm PrivateKey 
        { 
            get
            { 
                if ( !this.privateKeyAvailabilityDetermined )
                {
                    lock ( ThisLock )
                    { 
                        if ( !this.privateKeyAvailabilityDetermined )
                        { 
                            this.privateKey = this.certificate.PrivateKey; 
                            this.privateKeyAvailabilityDetermined = true;
                        } 
                    }
                }
                return this.privateKey;
            } 
        }
 
        PublicKey PublicKey 
        {
            get 
            {
                if ( this.publicKey == null )
                {
                    lock ( ThisLock ) 
                    {
                        if ( this.publicKey == null ) 
                        { 
                            this.publicKey = this.certificate.PublicKey;
                        } 
                    }
                }
                return this.publicKey;
            } 
        }
 
        Object ThisLock 
        {
            get 
            {
                return thisLock;
            }
        } 

        public override byte[] DecryptKey( string algorithm, byte[] keyData ) 
        { 
            // We can decrypt key only if we have the private key in the certificate.
            if ( this.PrivateKey == null ) 
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.MissingPrivateKey ) ) );
            }
 
            RSA rsa = this.PrivateKey as RSA;
            if ( rsa == null ) 
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotRSA ) ) );
            } 

            // Support exchange keySpec, AT_EXCHANGE ?
            if ( rsa.KeyExchangeAlgorithm == null )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyExchangeNotSupported ) ) );
            } 
 
            switch ( algorithm )
            { 
            case EncryptedXml.XmlEncRSA15Url:
                return EncryptedXml.DecryptKey( keyData, rsa, false );

            case EncryptedXml.XmlEncRSAOAEPUrl: 
                return EncryptedXml.DecryptKey( keyData, rsa, true );
 
            default: 
                if ( IsSupportedAlgorithm( algorithm ) )
                    return EncryptedXml.DecryptKey( keyData, rsa, true ); 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
            }
        } 

        public override byte[] EncryptKey( string algorithm, byte[] keyData ) 
        { 
            // Ensure that we have an RSA algorithm object
            RSA rsa = this.PublicKey.Key as RSA; 
            if ( rsa == null )
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PublicKeyNotRSA ) ) );
            } 

            switch ( algorithm ) 
            { 
            case EncryptedXml.XmlEncRSA15Url:
                return EncryptedXml.EncryptKey( keyData, rsa, false ); 

            case EncryptedXml.XmlEncRSAOAEPUrl:
                return EncryptedXml.EncryptKey( keyData, rsa, true );
 
            default:
                if ( IsSupportedAlgorithm( algorithm ) ) 
                    return EncryptedXml.EncryptKey( keyData, rsa, true ); 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) ); 
            }
        }

        public override AsymmetricAlgorithm GetAsymmetricAlgorithm( string algorithm, bool privateKey ) 
        {
            if ( privateKey ) 
            { 
                if ( this.PrivateKey == null )
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.MissingPrivateKey ) ) );
                }

                if ( String.IsNullOrEmpty( algorithm ) ) 
                {
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) ); 
                } 

                switch ( algorithm ) 
                {
                case SignedXml.XmlDsigDSAUrl:
                    if ( ( this.PrivateKey as DSA ) != null )
                    { 
                        return ( this.PrivateKey as DSA );
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPrivateKeyMisMatch ) ) ); 

                case SignedXml.XmlDsigRSASHA1Url: 
                case SecurityAlgorithms.RsaSha256Signature:
                case EncryptedXml.XmlEncRSA15Url:
                case EncryptedXml.XmlEncRSAOAEPUrl:
                    if ( ( this.PrivateKey as RSA ) != null ) 
                    {
                        return ( this.PrivateKey as RSA ); 
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPrivateKeyMisMatch ) ) );
                default: 
                    if ( IsSupportedAlgorithm( algorithm ) )
                        return this.PrivateKey;
                    else
                        throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) ); 
                }
            } 
            else 
            {
                switch ( algorithm ) 
                {
                case SignedXml.XmlDsigDSAUrl:
                    if ( ( this.PublicKey.Key as DSA ) != null )
                    { 
                        return ( this.PublicKey.Key as DSA );
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPublicKeyMisMatch ) ) ); 
                case SignedXml.XmlDsigRSASHA1Url:
                case SecurityAlgorithms.RsaSha256Signature: 
                case EncryptedXml.XmlEncRSA15Url:
                case EncryptedXml.XmlEncRSAOAEPUrl:
                    if ( ( this.PublicKey.Key as RSA ) != null )
                    { 
                        return ( this.PublicKey.Key as RSA );
                    } 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPublicKeyMisMatch ) ) ); 
                default:
 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
                }
            }
        } 

        public override HashAlgorithm GetHashAlgorithmForSignature( string algorithm ) 
        { 
            if ( String.IsNullOrEmpty( algorithm ) )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) );
            }

            object algorithmObject = CryptoHelper.GetAlgorithmFromConfig( algorithm ); 

            if ( algorithmObject != null ) 
            { 
                SignatureDescription description = algorithmObject as SignatureDescription;
                if ( description != null ) 
                    return description.CreateDigest();

                HashAlgorithm hashAlgorithm = algorithmObject as HashAlgorithm;
                if ( hashAlgorithm != null ) 
                    return hashAlgorithm;
 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new CryptographicException( SR.GetString( SR.UnsupportedAlgorithmForCryptoOperation, 
                        algorithm, "CreateDigest" ) ) );
            } 

            switch ( algorithm )
            {
            case SignedXml.XmlDsigDSAUrl: 
            case SignedXml.XmlDsigRSASHA1Url:
                return CryptoHelper.NewSha1HashAlgorithm(); 
            case SecurityAlgorithms.RsaSha256Signature: 
                return CryptoHelper.NewSha256HashAlgorithm();
            default: 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
            }
        }
 
        public override AsymmetricSignatureDeformatter GetSignatureDeformatter( string algorithm )
        { 
 
            // We support one of the two algoritms, but not both.
            //     XmlDsigDSAUrl = "http://www.w3.org/2000/09/xmldsig#dsa-sha1"; 
            //     XmlDsigRSASHA1Url = "http://www.w3.org/2000/09/xmldsig#rsa-sha1";

            if ( String.IsNullOrEmpty( algorithm ) )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) );
            } 
 
            object algorithmObject = CryptoHelper.GetAlgorithmFromConfig( algorithm );
            if ( algorithmObject != null ) 
            {
                SignatureDescription description = algorithmObject as SignatureDescription;
                if ( description != null )
                    return description.CreateDeformatter( this.PublicKey.Key ); 

                try 
                { 
                    AsymmetricSignatureDeformatter asymmetricSignatureDeformatter = algorithmObject as AsymmetricSignatureDeformatter;
                    if ( asymmetricSignatureDeformatter != null ) 
                    {
                        asymmetricSignatureDeformatter.SetKey( this.PublicKey.Key );
                        return asymmetricSignatureDeformatter;
                    } 
                }
                catch ( InvalidCastException e ) 
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPublicKeyMisMatch ), e ) );
                } 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new CryptographicException( SR.GetString( SR.UnsupportedAlgorithmForCryptoOperation,
                       algorithm, "GetSignatureDeformatter" ) ) );
            } 

            switch ( algorithm ) 
            { 
            case SignedXml.XmlDsigDSAUrl:
 
                // Ensure that we have a DSA algorithm object.
                DSA dsa = ( this.PublicKey.Key as DSA );
                if ( dsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PublicKeyNotDSA ) ) ); 
                return new DSASignatureDeformatter( dsa );
 
            case SignedXml.XmlDsigRSASHA1Url: 
            case SecurityAlgorithms.RsaSha256Signature:
                // Ensure that we have an RSA algorithm object. 
                RSA rsa = ( this.PublicKey.Key as RSA );
                if ( rsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PublicKeyNotRSA ) ) );
                return new RSAPKCS1SignatureDeformatter( rsa ); 

            default: 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) ); 
            }
        } 

        public override AsymmetricSignatureFormatter GetSignatureFormatter( string algorithm )
        {
            // One can sign only if the private key is present. 
            if ( this.PrivateKey == null )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.MissingPrivateKey ) ) ); 
            }
 
            if ( String.IsNullOrEmpty( algorithm ) )
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) );
            } 
            // We support one of the two algoritms, but not both.
            //     XmlDsigDSAUrl = "http://www.w3.org/2000/09/xmldsig#dsa-sha1"; 
            //     XmlDsigRSASHA1Url = "http://www.w3.org/2000/09/xmldsig#rsa-sha1"; 
            object algorithmObject = CryptoHelper.GetAlgorithmFromConfig( algorithm );
            if ( algorithmObject != null ) 
            {
                SignatureDescription description = algorithmObject as SignatureDescription;
                if ( description != null )
                    return description.CreateFormatter( this.PrivateKey ); 

                try 
                { 
                    AsymmetricSignatureFormatter asymmetricSignatureFormatter = algorithmObject as AsymmetricSignatureFormatter;
                    if ( asymmetricSignatureFormatter != null ) 
                    {
                        asymmetricSignatureFormatter.SetKey( this.PrivateKey );
                        return asymmetricSignatureFormatter;
                    } 
                }
                catch ( InvalidCastException e ) 
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.AlgorithmAndPrivateKeyMisMatch ), e ) );
                } 

                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new CryptographicException( SR.GetString( SR.UnsupportedAlgorithmForCryptoOperation,
                       algorithm, "GetSignatureFormatter" ) ) );
            } 

            switch ( algorithm ) 
            { 
            case SignedXml.XmlDsigDSAUrl:
 
                // Ensure that we have a DSA algorithm object.
                DSA dsa = ( this.PrivateKey as DSA );
                if ( dsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotDSA ) ) ); 
                return new DSASignatureFormatter( dsa );
 
            case SignedXml.XmlDsigRSASHA1Url: 
                // Ensure that we have an RSA algorithm object.
                RSA rsa = ( this.PrivateKey as RSA ); 
                if ( rsa == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotRSA ) ) );
                return new RSAPKCS1SignatureFormatter( rsa );
 
            case SecurityAlgorithms.RsaSha256Signature:
                // Ensure that we have an RSA algorithm object. 
                RSACryptoServiceProvider rsa_prov_full = ( this.PrivateKey as RSACryptoServiceProvider ); 
                if ( rsa_prov_full == null )
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.PrivateKeyNotRSA ) ) ); 
                CspParameters csp = new CspParameters();
                csp.ProviderType = 24;
                csp.KeyContainerName = rsa_prov_full.CspKeyContainerInfo.KeyContainerName;
                csp.KeyNumber = (int)rsa_prov_full.CspKeyContainerInfo.KeyNumber; 
                if ( rsa_prov_full.CspKeyContainerInfo.MachineKeyStore )
                    csp.Flags = CspProviderFlags.UseMachineKeyStore; 
                return new RSAPKCS1SignatureFormatter( new RSACryptoServiceProvider( csp ) ); 

            default: 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError( new NotSupportedException( SR.GetString( SR.UnsupportedCryptoAlgorithm, algorithm ) ) );
            }

        } 

        public override bool HasPrivateKey() 
        { 
            return ( this.PrivateKey != null );
        } 

        public override bool IsAsymmetricAlgorithm( string algorithm )
        {
            if ( String.IsNullOrEmpty( algorithm ) ) 
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) ); 
            } 

            return ( CryptoHelper.IsAsymmetricAlgorithm( algorithm ) ); 
        }

        public override bool IsSupportedAlgorithm( string algorithm )
        { 
            if ( String.IsNullOrEmpty( algorithm ) )
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgument( algorithm, SR.GetString( SR.EmptyOrNullArgumentString, "algorithm" ) ); 
            }
 
            object algorithmObject = null;
            try
            {
                algorithmObject =  CryptoHelper.GetAlgorithmFromConfig( algorithm ); 
            }
            catch (InvalidOperationException) 
            { 
                algorithm = null;
            } 

            if ( algorithmObject != null )
            {
                SignatureDescription signatureDescription = algorithmObject as SignatureDescription; 
                if ( signatureDescription != null )
                    return true; 
                AsymmetricAlgorithm asymmetricAlgorithm = algorithmObject as AsymmetricAlgorithm; 
                if ( asymmetricAlgorithm != null )
                    return true; 
                return false;
            }

            switch ( algorithm ) 
            {
            case SignedXml.XmlDsigDSAUrl: 
                return ( this.PublicKey.Key is DSA ); 

            case SignedXml.XmlDsigRSASHA1Url: 
            case SecurityAlgorithms.RsaSha256Signature:
            case EncryptedXml.XmlEncRSA15Url:
            case EncryptedXml.XmlEncRSAOAEPUrl:
                return ( this.PublicKey.Key is RSA ); 
            default:
                return false; 
            } 
        }
 
        public override bool IsSymmetricAlgorithm( string algorithm )
        {
            return CryptoHelper.IsSymmetricAlgorithm( algorithm );
        } 
    }
} 

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

                        

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