示例#1
0
        public override sealed string ToString()
        {
            StringBuilder bb = new StringBuilder();

            bb.Append("Version: ");
            bb.AppendLine(Version.ToString());
            bb.Append("SerialNumber: ");
            bb.AppendLine(SerialNumber.ToString());
            bb.Append("Signature: ");
            bb.Append(SignatureAlgorithm.ToString());
            bb.Append(", OID = ");
            bb.Append(HashAlgorithmConverter.GetString(SignatureAlgorithm));
            bb.Append("\n");
            bb.Append("Issuer: ");
            bb.Append(Issuer);
            bb.Append("\n");
            bb.Append("Validity: [From: ");
            bb.Append(ValidFrom.ToUniversalTime().ToString());
            bb.Append(" GMT To: ");
            bb.Append(ValidTo.ToUniversalTime().ToString());
            bb.Append(" GMT]\n");
            bb.Append("Subject: ");
            bb.Append(Subject);
            bb.Append("\n");
            bb.Append("Public Key Algorithm: ");
            bb.Append(PublicKeyAlgorithm.ToString());
            bb.Append("\n");
            bb.Append("Key: ");
            bb.Append(PublicKey.ToHex());
            bb.Append("\n");
            if (PublicKey.Scheme == Ecdsa.Enums.Ecc.P256)
            {
                bb.Append("ASN1 OID: prime256v1\n");
                bb.Append("NIST CURVE: P-256");
            }
            else if (PublicKey.Scheme == Ecdsa.Enums.Ecc.P384)
            {
                bb.Append("ASN1 OID: prime384v1\n");
                bb.Append("\n");
                bb.Append("NIST CURVE: P-384");
            }
            bb.Append("\n");
            bb.Append("Basic constraints: ");
            bb.Append(BasicConstraints);
            bb.Append("\n");
            bb.Append("SubjectKeyIdentifier: ");
            bb.Append(GXCommon.ToHex(SubjectKeyIdentifier, true));
            bb.Append("\n");
            bb.Append("KeyUsage: ");
            bb.Append(KeyUsage);
            bb.Append("\n");
            bb.Append("Signature Algorithm: ");
            bb.Append(SignatureAlgorithm.ToString());
            bb.Append("\n");
            bb.Append("Signature: ");
            bb.Append(GXCommon.ToHex(Signature, false));
            bb.Append("\n");
            return(bb.ToString());
        }
示例#2
0
        private void Init(byte[] data)
        {
            GXAsn1Sequence seq = (GXAsn1Sequence)GXAsn1Converter.FromByteArray(data);

            if (seq.Count < 3)
            {
                throw new System.ArgumentException("Wrong number of elements in sequence.");
            }
            /////////////////////////////
            // CertificationRequestInfo ::= SEQUENCE {
            // version INTEGER { v1(0) } (v1,...),
            // subject Name,
            // subjectPKInfo SubjectPublicKeyInfo{{ PKInfoAlgorithms }},
            // attributes [0] Attributes{{ CRIAttributes }}
            // }

            GXAsn1Sequence reqInfo = (GXAsn1Sequence)seq[0];

            Version = (CertificateVersion)(sbyte)reqInfo[0];
            Subject = GXAsn1Converter.GetSubject((GXAsn1Sequence)reqInfo[1]);
            // subject Public key info.
            GXAsn1Sequence subjectPKInfo = (GXAsn1Sequence)reqInfo[2];

            if (reqInfo.Count > 3)
            {
                Attributes = reqInfo[3];
            }
            GXAsn1Sequence tmp = (GXAsn1Sequence)subjectPKInfo[0];

            Algorithm = PkcsObjectIdentifierConverter.FromString(tmp[0].ToString());
            if ((PkcsObjectIdentifier)Algorithm == PkcsObjectIdentifier.None)
            {
                Algorithm = X9ObjectIdentifierConverter.FromString(tmp[0].ToString());
            }
            byte[] encodedKey = GXAsn1Converter.ToByteArray(subjectPKInfo);
            PublicKey = GXPublicKey.FromRawBytes(encodedKey);
            /////////////////////////////
            // signatureAlgorithm
            GXAsn1Sequence sign = (GXAsn1Sequence)seq[1];

            SignatureAlgorithm = HashAlgorithmConverter.FromString(sign[0].ToString());
            if (sign.Count != 1)
            {
                SignatureParameters = sign[1];
            }
            /////////////////////////////
            // signature
            Signature = ((GXAsn1BitString)seq[2]).Value;
            GXEcdsa e = new GXEcdsa(PublicKey);

            if (!e.Verify(GXAsn1Converter.ToByteArray(reqInfo), data))
            {
                throw new ArgumentException("Invalid Signature.");
            }
        }
        public override sealed string ToString()
        {
            StringBuilder bb = new StringBuilder();

            bb.Append("Version: ");
            bb.Append(Version.ToString());
            bb.Append("\n");
            bb.Append("Subject: ");
            bb.Append(Subject);
            bb.Append("\n");

            bb.Append("Signature: ");
            bb.Append(SignatureAlgorithm.ToString());
            bb.Append(", OID = ");
            bb.Append(HashAlgorithmConverter.GetString(SignatureAlgorithm));
            bb.Append("\n");
            bb.Append("Key: ");
            if (PublicKey != null)
            {
                bb.Append(PublicKey.ToString());
            }
            bb.Append("\n");
            bb.Append("Validity: [From: ");
            bb.Append(ValidFrom.ToString());
            bb.Append(", \n");
            bb.Append("To: ");
            bb.Append(ValidTo.ToString());
            bb.Append("]\n");
            bb.Append("Issuer: ");
            bb.Append(Issuer);
            bb.Append("\n");
            bb.Append("SerialNumber: ");
            bb.Append(SerialNumber);
            bb.Append("\n");
            bb.Append("Algorithm: ");
            bb.Append(PublicKeySignature.ToString());
            bb.Append("\n");
            bb.Append("Signature: ");
            bb.Append(GXCommon.ToHex(Signature, false));
            bb.Append("\n");
            return(bb.ToString());
        }
示例#4
0
        private void Init(byte[] data)
        {
            Attributes = new List <KeyValuePair <PkcsObjectIdentifier, object[]> >();
            GXAsn1Sequence seq = (GXAsn1Sequence)GXAsn1Converter.FromByteArray(data);

            if (seq.Count < 3)
            {
                throw new System.ArgumentException("Wrong number of elements in sequence.");
            }
            /////////////////////////////
            // CertificationRequestInfo ::= SEQUENCE {
            // version INTEGER { v1(0) } (v1,...),
            // subject Name,
            // subjectPKInfo SubjectPublicKeyInfo{{ PKInfoAlgorithms }},
            // attributes [0] Attributes{{ CRIAttributes }}
            // }

            GXAsn1Sequence reqInfo = (GXAsn1Sequence)seq[0];

            Version = (CertificateVersion)(sbyte)reqInfo[0];
            Subject = GXAsn1Converter.GetSubject((GXAsn1Sequence)reqInfo[1]);
            // subject Public key info.
            GXAsn1Sequence subjectPKInfo = (GXAsn1Sequence)reqInfo[2];

            if (reqInfo.Count > 3)
            {
                //PkcsObjectIdentifier
                foreach (GXAsn1Sequence it in (GXAsn1Context)reqInfo[3])
                {
                    List <object> values = new List <object>();
                    foreach (object v in (List <object>)((KeyValuePair <object, object>)it[1]).Key)
                    {
                        values.Add(v);
                    }
                    Attributes.Add(new KeyValuePair <PkcsObjectIdentifier, object[]>(PkcsObjectIdentifierConverter.FromString(it[0].ToString()), values.ToArray()));
                }
            }
            GXAsn1Sequence tmp = (GXAsn1Sequence)subjectPKInfo[0];

            Algorithm = X9ObjectIdentifierConverter.FromString(tmp[0].ToString());
            if (Algorithm != X9ObjectIdentifier.IdECPublicKey)
            {
                object algorithm = Algorithm;
                if (Algorithm == X9ObjectIdentifier.None)
                {
                    algorithm = PkcsObjectIdentifierConverter.FromString(tmp[0].ToString());
                    if ((PkcsObjectIdentifier)algorithm == PkcsObjectIdentifier.None)
                    {
                        algorithm = tmp[0].ToString();
                    }
                }
                throw new Exception("Invalid PKCS #10 certificate algorithm. " + algorithm);
            }
            PublicKey = GXPublicKey.FromRawBytes(((GXAsn1BitString)subjectPKInfo[1]).Value);
            GXEcdsa.Validate(PublicKey);
            /////////////////////////////
            // signatureAlgorithm
            GXAsn1Sequence sign = (GXAsn1Sequence)seq[1];

            SignatureAlgorithm = HashAlgorithmConverter.FromString(sign[0].ToString());
            if (SignatureAlgorithm != HashAlgorithm.Sha256WithEcdsa && SignatureAlgorithm != HashAlgorithm.Sha384WithEcdsa)
            {
                throw new GXDLMSCertificateException("Invalid signature algorithm. " + sign[0].ToString());
            }
            if (sign.Count != 1)
            {
                SignatureParameters = sign[1];
            }
            /////////////////////////////
            // signature
            Signature = ((GXAsn1BitString)seq[2]).Value;
            GXEcdsa        e    = new GXEcdsa(PublicKey);
            GXAsn1Sequence tmp2 = (GXAsn1Sequence)GXAsn1Converter.FromByteArray(Signature);
            GXByteBuffer   bb   = new GXByteBuffer();
            int            size = SignatureAlgorithm == HashAlgorithm.Sha256WithEcdsa ? 32 : 48;

            //Some implementations might add extra byte. It must removed.
            bb.Set(((GXAsn1Integer)tmp2[0]).Value, ((GXAsn1Integer)tmp2[0]).Value.Length == size ? 0 : 1, size);
            bb.Set(((GXAsn1Integer)tmp2[1]).Value, ((GXAsn1Integer)tmp2[1]).Value.Length == size ? 0 : 1, size);
            if (!e.Verify(bb.Array(), GXAsn1Converter.ToByteArray(reqInfo)))
            {
                throw new ArgumentException("Invalid Signature.");
            }
        }
示例#5
0
        private object[] GetDataList()
        {
            if (string.IsNullOrEmpty(Issuer))
            {
                throw new ArgumentNullException("Issuer is empty.");
            }
            if (string.IsNullOrEmpty(Subject))
            {
                throw new ArgumentNullException("Subject is empty.");
            }
            GXAsn1ObjectIdentifier a = new GXAsn1ObjectIdentifier(HashAlgorithmConverter.GetString(SignatureAlgorithm));
            GXAsn1Sequence         seq;
            GXAsn1Context          p = new GXAsn1Context();

            p.Add((sbyte)Version);
            GXAsn1Sequence s = new GXAsn1Sequence();
            GXAsn1Sequence s1;

            if (SubjectKeyIdentifier != null)
            {
                s1 = new GXAsn1Sequence();
                s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.SubjectKeyIdentifier)));
                GXByteBuffer bb = new GXByteBuffer();
                bb.SetUInt8(BerType.OctetString);
                GXCommon.SetObjectCount(SubjectKeyIdentifier.Length, bb);
                bb.Set(SubjectKeyIdentifier);
                s1.Add(bb.Array());
                s.Add(s1);
            }
            if (AuthorityKeyIdentifier != null || AuthorityCertIssuer != null || AuthorityCertificationSerialNumber != null)
            {
                s1 = new GXAsn1Sequence();
                s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.AuthorityKeyIdentifier)));
                s.Add(s1);
                GXAsn1Context s2 = new GXAsn1Context()
                {
                    Index = 3
                };
                GXAsn1Sequence c1 = new GXAsn1Sequence();
                if (AuthorityKeyIdentifier != null)
                {
                    GXAsn1Context c4 = new GXAsn1Context()
                    {
                        Constructed = false, Index = 0
                    };
                    c4.Add(AuthorityKeyIdentifier);
                    c1.Add(c4);
                    s1.Add(GXAsn1Converter.ToByteArray(c1));
                }
                if (AuthorityCertIssuer != null)
                {
                    GXAsn1Context c2 = new GXAsn1Context();
                    c2.Index = 1;
                    c1.Add(c2);
                    GXAsn1Context c3 = new GXAsn1Context()
                    {
                        Index = 4
                    };
                    c2.Add(c3);
                    c3.Add(GXAsn1Converter.EncodeSubject(AuthorityCertIssuer));
                    s2.Add(c1);
                }
                if (AuthorityCertificationSerialNumber != null)
                {
                    GXAsn1Context c4 = new GXAsn1Context()
                    {
                        Constructed = false, Index = 2
                    };
                    c4.Add(AuthorityCertificationSerialNumber);
                    c1.Add(c4);
                    s1.Add(GXAsn1Converter.ToByteArray(c1));
                }
            }
            // BasicConstraints
            s1 = new GXAsn1Sequence();
            s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.BasicConstraints)));
            seq = new GXAsn1Sequence();
            if (BasicConstraints)
            {
                //BasicConstraints is critical if it exists.
                s1.Add(BasicConstraints);
            }
            else if (KeyUsage == KeyUsage.None)
            {
                throw new Exception("Key usage not present.");
            }
            s1.Add(GXAsn1Converter.ToByteArray(seq));
            s.Add(s1);
            s1 = new GXAsn1Sequence();
            s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.KeyUsage)));
            byte value    = 0;
            int  min      = 255;
            byte keyUsage = GXCommon.SwapBits((byte)KeyUsage);

            foreach (KeyUsage it in Enum.GetValues(typeof(KeyUsage)))
            {
                if ((((byte)it) & keyUsage) != 0)
                {
                    byte val = (byte)it;
                    value |= val;
                    if (val < min)
                    {
                        min = val;
                    }
                }
            }
            int ignore = 0;

            while ((min >>= 1) != 0)
            {
                ++ignore;
            }
            byte[] tmp = GXAsn1Converter.ToByteArray(new GXAsn1BitString(new byte[] { (byte)(ignore % 8), value }));
            s1.Add(tmp);
            s.Add(s1);
            GXAsn1Sequence valid = new GXAsn1Sequence();

            valid.Add(ValidFrom);
            valid.Add(ValidTo);
            GXAsn1ObjectIdentifier alg;

            if (PublicKey.Scheme == Ecdsa.Enums.Ecc.P256)
            {
                alg = new GXAsn1ObjectIdentifier("1.2.840.10045.3.1.7");
            }
            else
            {
                alg = new GXAsn1ObjectIdentifier("1.3.132.0.34");
            }
            object[] list;
            object[] tmp3 = new object[] { new GXAsn1ObjectIdentifier("1.2.840.10045.2.1"),
                                           alg };
            GXAsn1Context tmp4 = new GXAsn1Context();

            tmp4.Index = 3;
            tmp4.Add(s);
            object[] tmp2 = new object[] { tmp3, new GXAsn1BitString(PublicKey.RawValue, 0) };
            object[] p2;
            if (SignatureParameters == null)
            {
                p2 = new object[] { a };
            }
            else
            {
                p2 = new object[] { a, SignatureParameters };
            }
            list = new object[] { p, new GXAsn1Integer(SerialNumber.ToByteArray()), p2, GXAsn1Converter.EncodeSubject(Issuer), valid, GXAsn1Converter.EncodeSubject(Subject), tmp2, tmp4 };
            return(list);
        }
示例#6
0
        //  https://tools.ietf.org/html/rfc5280#section-4.1
        private void Init(byte[] data)
        {
            rawData = data;
            GXAsn1Sequence seq = (GXAsn1Sequence)GXAsn1Converter.FromByteArray(data);

            if (seq.Count != 3)
            {
                throw new GXDLMSCertificateException("Invalid Certificate Version. Wrong number of elements in sequence.");
            }
            if (!(seq[0] is GXAsn1Sequence))
            {
                PkcsType type = GXAsn1Converter.GetCertificateType(data, seq);
                switch (type)
                {
                case PkcsType.Pkcs8:
                    throw new GXDLMSCertificateException("Invalid Certificate. This is PKCS 8 private key, not x509 certificate.");

                case PkcsType.Pkcs10:
                    throw new GXDLMSCertificateException("Invalid Certificate. This is PKCS 10 certification requests, not x509 certificate.");
                }
                throw new GXDLMSCertificateException("Invalid Certificate Version.");
            }
            GXAsn1Sequence reqInfo = (GXAsn1Sequence)seq[0];

            if ((reqInfo[0] is GXAsn1Integer))
            {
                throw new GXDLMSCertificateException("Invalid Certificate. DLMS certificate version number must be 3.");
            }
            Version = (CertificateVersion)((GXAsn1Context)reqInfo[0])[0];
            if (reqInfo[1] is sbyte)
            {
                SerialNumber = Convert.ToUInt64(reqInfo[1]);
            }
            else
            {
                SerialNumber = new BigInteger(((GXAsn1Integer)reqInfo[1]).Value);
            }
            string tmp = ((GXAsn1Sequence)reqInfo[2])[0].ToString();

            // Signature Algorithm
            SignatureAlgorithm = HashAlgorithmConverter.FromString(tmp);
            if (SignatureAlgorithm != HashAlgorithm.Sha256WithEcdsa)
            {
                throw new Exception("DLMS certificate must be signed with ecdsa-with-SHA256.");
            }
            // Optional.
            if (((GXAsn1Sequence)reqInfo[2]).Count > 1)
            {
                SignatureParameters = ((GXAsn1Sequence)reqInfo[2])[1];
            }
            // Issuer
            Issuer = GXAsn1Converter.GetSubject((GXAsn1Sequence)reqInfo[3]);
            bool basicConstraintsExists = false;

            // Validity
            ValidFrom = (DateTime)((GXAsn1Sequence)reqInfo[4])[0];
            ValidTo   = (DateTime)((GXAsn1Sequence)reqInfo[4])[1];
            Subject   = GXAsn1Converter.GetSubject((GXAsn1Sequence)reqInfo[5]);
            string CN = X509NameConverter.GetString(X509Name.CN);
            // Subject public key Info
            GXAsn1Sequence subjectPKInfo = (GXAsn1Sequence)reqInfo[6];

            PublicKey = GXPublicKey.FromRawBytes(((GXAsn1BitString)subjectPKInfo[1]).Value);
            GXEcdsa.Validate(PublicKey);
            // Get Standard Extensions.
            if (reqInfo.Count > 7)
            {
                foreach (GXAsn1Sequence s in (GXAsn1Sequence)((GXAsn1Context)reqInfo[7])[0])
                {
                    GXAsn1ObjectIdentifier id = (GXAsn1ObjectIdentifier)s[0];
                    object value          = s[1];
                    X509CertificateType t = X509CertificateTypeConverter.FromString(id.ToString());
                    switch (t)
                    {
                    case X509CertificateType.SubjectKeyIdentifier:
                        SubjectKeyIdentifier = (byte[])value;
                        break;

                    case X509CertificateType.AuthorityKeyIdentifier:
                        foreach (GXAsn1Context it in (GXAsn1Sequence)value)
                        {
                            switch (it.Index)
                            {
                            case 0:
                                //Authority Key Identifier.
                                AuthorityKeyIdentifier = (byte[])it[0];
                                break;

                            case 1:
                            {
                                StringBuilder sb = new StringBuilder();
                                //authorityCertIssuer
                                foreach (KeyValuePair <object, object> it2 in ((GXAsn1Sequence)((GXAsn1Context)it[0])[0]))
                                {
                                    if (sb.Length != 0)
                                    {
                                        sb.Append(", ");
                                    }
                                    sb.Append(X509NameConverter.FromString(Convert.ToString(it2.Key)));
                                    sb.Append("=");
                                    sb.Append(Convert.ToString(it2.Value));
                                }
                                AuthorityCertIssuer = sb.ToString();
                            }
                            break;

                            case 2:
                                //Authority cert serial number .
                                AuthorityCertificationSerialNumber = (byte[])it[0];
                                break;

                            default:
                                throw new ArgumentOutOfRangeException("Invalid context." + it.Index);
                            }
                        }
                        break;

                    case X509CertificateType.KeyUsage:
                        if (value is GXAsn1BitString)
                        {
                            // critical is optional. BOOLEAN DEFAULT FALSE,
                            KeyUsage = (KeyUsage)((GXAsn1BitString)value).ToInteger();
                        }
                        else if (value is bool?)
                        {
                            value    = s[2];
                            KeyUsage = (KeyUsage)((GXAsn1BitString)value).ToInteger();
                        }
                        else
                        {
                            throw new ArgumentException("Invalid key usage.");
                        }
                        break;

                    case X509CertificateType.BasicConstraints:
                        basicConstraintsExists = true;
                        if (value is GXAsn1Sequence)
                        {
                            if (((GXAsn1Sequence)value).Count != 0)
                            {
                                BasicConstraints = (bool)((GXAsn1Sequence)value)[0];
                            }
                        }
                        else if (value is bool?)
                        {
                            BasicConstraints = (bool)value;
                        }
                        else
                        {
                            throw new ArgumentException("Invalid key usage.");
                        }
                        break;

                    default:
                        System.Diagnostics.Debug.WriteLine("Unknown extensions: " + t.ToString());
                        break;
                    }
                }
            }
            if (!basicConstraintsExists)
            {
                // Verify that subject Common Name includes system title.
                bool commonNameFound = false;
                foreach (KeyValuePair <object, object> it in (GXAsn1Sequence)reqInfo[5])
                {
                    if (CN == it.Key.ToString())
                    {
                        if (Convert.ToString(it.Value).Length != 16)
                        {
                            throw new GXDLMSCertificateException("System title is not included in Common Name.");
                        }
                        commonNameFound = true;
                        break;
                    }
                }
                if (!commonNameFound)
                {
                    throw new GXDLMSCertificateException("Common name doesn't exist.");
                }
            }

            if (KeyUsage == KeyUsage.None)
            {
                throw new Exception("Key usage not present. It's mandotory.");
            }
            if ((KeyUsage & (KeyUsage.KeyCertSign | KeyUsage.CrlSign)) != 0 && !basicConstraintsExists)
            {
                throw new Exception("Basic Constraints value not present. It's mandotory.");
            }
            PublicKeyAlgorithm = HashAlgorithmConverter.FromString(((GXAsn1Sequence)seq[1])[0].ToString());
            if (PublicKeyAlgorithm != HashAlgorithm.Sha256WithEcdsa)
            {
                throw new Exception("DLMS certificate must be signed with ecdsa-with-SHA256.");
            }
            // Optional.
            if (((GXAsn1Sequence)seq[1]).Count > 1)
            {
                PublicKeyParameters = ((GXAsn1Sequence)seq[1])[1];
            }
            /////////////////////////////
            //Get signature.
            Signature = ((GXAsn1BitString)seq[2]).Value;
        }
        private object[] GetData()
        {
            GXAsn1ObjectIdentifier a = new GXAsn1ObjectIdentifier(HashAlgorithmConverter.GetString(SignatureAlgorithm));
            GXAsn1Context          p = new GXAsn1Context();

            p.Add((sbyte)Version);
            object         subjectPKInfo = GXAsn1Converter.FromByteArray(PublicKey.RawValue);
            GXAsn1Sequence s             = new GXAsn1Sequence();
            GXAsn1Sequence s1;

            if (SubjectKeyIdentifier != null)
            {
                s1 = new GXAsn1Sequence();
                s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.SubjectKeyIdentifier)));
                GXByteBuffer bb = new GXByteBuffer();
                bb.SetUInt8(BerType.OctetString);
                GXCommon.SetObjectCount(SubjectKeyIdentifier.Length, bb);
                bb.Set(SubjectKeyIdentifier);
                s1.Add(bb.Array());
                s.Add(s1);
            }
            if (AuthorityKeyIdentifier != null)
            {
                s1 = new GXAsn1Sequence();
                s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.AuthorityKeyIdentifier)));
                GXAsn1Sequence seq = new GXAsn1Sequence();
                seq.Add(AuthorityKeyIdentifier);
                s1.Add(GXAsn1Converter.ToByteArray(seq));
                s.Add(s1);
            }
            if (BasicConstraints)
            {
                s1 = new GXAsn1Sequence();
                s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.BasicConstraints)));
                GXAsn1Sequence seq = new GXAsn1Sequence();
                seq.Add(BasicConstraints);
                s1.Add(GXAsn1Converter.ToByteArray(seq));
                s.Add(s1);
            }
            if (KeyUsage == KeyUsage.None)
            {
                throw new Exception("Key usage not present.");
            }
            s1 = new GXAsn1Sequence();
            s1.Add(new GXAsn1ObjectIdentifier(X509CertificateTypeConverter.GetString(Enums.X509CertificateType.KeyUsage)));
            byte value = 0;
            int  min   = 255;

            foreach (KeyUsage it in Enum.GetValues(typeof(KeyUsage)))
            {
                if ((it & KeyUsage) != 0)
                {
                    byte val = (byte)it;
                    value |= val;
                    if (val < min)
                    {
                        min = val;
                    }
                }
            }
            int offset = 7;

            while ((min >>= 2) != 0)
            {
                ++offset;
            }
            byte[] tmp = GXAsn1Converter.ToByteArray(new GXAsn1BitString(new byte[] { 0, value }));
            s1.Add(tmp);
            s.Add(s1);
            GXAsn1Sequence valid = new GXAsn1Sequence();

            valid.Add(ValidFrom);
            valid.Add(ValidTo);
            object[] list;
            if (s.Count == 0)
            {
                list = new object[] { p, SerialNumber, new object[] { a, SignatureParameters }, GXAsn1Converter.EncodeSubject(Issuer), valid, GXAsn1Converter.EncodeSubject(Subject), subjectPKInfo };
            }
            else
            {
                GXAsn1Context tmp2 = new GXAsn1Context();
                tmp2.Index = 3;
                tmp2.Add(s);
                list = new object[] { p, SerialNumber, new object[] { a, SignatureParameters }, GXAsn1Converter.EncodeSubject(Issuer), valid, GXAsn1Converter.EncodeSubject(Subject), subjectPKInfo, tmp2 };
            }
            return(list);
        }
        //  https://tools.ietf.org/html/rfc5280#section-4.1
        private void Init(byte[] data)
        {
            GXAsn1Sequence seq = (GXAsn1Sequence)GXAsn1Converter.FromByteArray(data);

            if (seq.Count != 3)
            {
                throw new ArgumentException("Wrong number of elements in sequence.");
            }
            GXAsn1Sequence reqInfo = (GXAsn1Sequence)seq[0];

            Version = (CertificateVersion)((GXAsn1Context)reqInfo[0])[0];
            if (reqInfo[1] is sbyte)
            {
                SerialNumber = new GXAsn1Integer(Convert.ToUInt64(reqInfo[1]));
            }
            else
            {
                SerialNumber = (GXAsn1Integer)reqInfo[1];
            }
            string tmp = ((GXAsn1Sequence)reqInfo[2])[0].ToString();

            // Signature Algorithm
            SignatureAlgorithm = HashAlgorithmConverter.FromString(tmp);
            if (SignatureAlgorithm != HashAlgorithm.Sha256withecdsa)
            {
                throw new Exception("DLMS certificate must be signed with ecdsa-with-SHA256.");
            }
            // Optional.
            if (((GXAsn1Sequence)reqInfo[2]).Count > 1)
            {
                SignatureParameters = ((GXAsn1Sequence)reqInfo[2])[1];
            }
            // Issuer
            Issuer = GXAsn1Converter.GetSubject((GXAsn1Sequence)reqInfo[3]);
            // Validity
            ValidFrom = (DateTime)((GXAsn1Sequence)reqInfo[4])[0];
            ValidTo   = (DateTime)((GXAsn1Sequence)reqInfo[4])[1];
            Subject   = GXAsn1Converter.GetSubject((GXAsn1Sequence)reqInfo[5]);
            // Subject public key Info
            GXAsn1Sequence subjectPKInfo = (GXAsn1Sequence)reqInfo[6];

            PublicKey = GXPublicKey.FromRawBytes(((GXAsn1BitString)subjectPKInfo[1]).Value);
            // Get Standard Extensions.
            if (reqInfo.Count > 7)
            {
                foreach (GXAsn1Sequence s in (GXAsn1Sequence)((GXAsn1Context)reqInfo[7])[0])
                {
                    GXAsn1ObjectIdentifier id = (GXAsn1ObjectIdentifier)s[0];
                    object value = s[1];
                    Enums.X509CertificateType t = Enums.X509CertificateTypeConverter.FromString(id.ToString());
                    switch (t)
                    {
                    case Enums.X509CertificateType.SubjectKeyIdentifier:
                        SubjectKeyIdentifier = (byte[])value;
                        break;

                    case Enums.X509CertificateType.AuthorityKeyIdentifier:
                        AuthorityKeyIdentifier = (byte[])((GXAsn1Sequence)value)[0];
                        break;

                    case Enums.X509CertificateType.KeyUsage:
                        if (value is GXAsn1BitString)
                        {
                            // critical is optional. BOOLEAN DEFAULT FALSE,
                            KeyUsage = (KeyUsage)((GXAsn1BitString)value).Value[0];
                        }
                        else if (value is bool?)
                        {
                            value    = s[2];
                            KeyUsage = (KeyUsage)((GXAsn1BitString)value).Value[0];
                        }
                        else
                        {
                            throw new ArgumentException("Invalid key usage.");
                        }
                        break;

                    default:
                        System.Diagnostics.Debug.WriteLine("Unknown extensions: " + t.ToString());
                        break;
                    }
                }
            }
            if (KeyUsage == KeyUsage.None)
            {
                throw new Exception("Key usage not present.");
            }
            PublicKeySignature = HashAlgorithmConverter.FromString(((GXAsn1Sequence)seq[1])[0].ToString());
            // Optional.
            if (((GXAsn1Sequence)seq[1]).Count > 1)
            {
                SignatureParameters = ((GXAsn1Sequence)seq[1])[1];
            }
            // signature
            Signature = ((GXAsn1BitString)seq[2]).Value;
        }