Initial import of old CVS repository

1 files changed, 1937 insertions, 0 deletions

diff --git a/crypto/src/pkix/PkixNameConstraintValidator.cs b/crypto/src/pkix/PkixNameConstraintValidator.cs
new file mode 100644
index 000000000..535f95174
--- /dev/null
+++ b/crypto/src/pkix/PkixNameConstraintValidator.cs
@@ -0,0 +1,1937 @@
+using System;
+using System.Collections;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.Collections;
+
+namespace Org.BouncyCastle.Pkix
+{
+    public class PkixNameConstraintValidator
+    {
+        private ISet excludedSubtreesDN = new HashSet();
+
+        private ISet excludedSubtreesDNS = new HashSet();
+
+        private ISet excludedSubtreesEmail = new HashSet();
+
+        private ISet excludedSubtreesURI = new HashSet();
+
+        private ISet excludedSubtreesIP = new HashSet();
+
+        private ISet permittedSubtreesDN;
+
+        private ISet permittedSubtreesDNS;
+
+        private ISet permittedSubtreesEmail;
+
+        private ISet permittedSubtreesURI;
+
+        private ISet permittedSubtreesIP;
+
+        public PkixNameConstraintValidator()
+        {
+        }
+
+        private static bool WithinDNSubtree(
+            Asn1Sequence dns,
+            Asn1Sequence subtree)
+        {
+            if (subtree.Count < 1)
+            {
+                return false;
+            }
+
+            if (subtree.Count > dns.Count)
+            {
+                return false;
+            }
+
+            for (int j = subtree.Count - 1; j >= 0; j--)
+            {
+                if (!(subtree[j].Equals(dns[j])))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        public void CheckPermittedDN(Asn1Sequence dns)
+        //throws PkixNameConstraintValidatorException
+        {
+            CheckPermittedDN(permittedSubtreesDN, dns);
+        }
+
+        public void CheckExcludedDN(Asn1Sequence dns)
+        //throws PkixNameConstraintValidatorException
+        {
+            CheckExcludedDN(excludedSubtreesDN, dns);
+        }
+
+        private void CheckPermittedDN(ISet permitted, Asn1Sequence dns)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (permitted == null)
+            {
+                return;
+            }
+
+            if ((permitted.Count == 0) && dns.Count == 0)
+            {
+                return;
+            }
+
+            IEnumerator it = permitted.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                Asn1Sequence subtree = (Asn1Sequence)it.Current;
+
+                if (WithinDNSubtree(dns, subtree))
+                {
+                    return;
+                }
+            }
+
+            throw new PkixNameConstraintValidatorException(
+                "Subject distinguished name is not from a permitted subtree");
+        }
+
+        private void CheckExcludedDN(ISet excluded, Asn1Sequence dns)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (excluded.IsEmpty)
+            {
+                return;
+            }
+
+            IEnumerator it = excluded.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                Asn1Sequence subtree = (Asn1Sequence)it.Current;
+
+                if (WithinDNSubtree(dns, subtree))
+                {
+                    throw new PkixNameConstraintValidatorException(
+                        "Subject distinguished name is from an excluded subtree");
+                }
+            }
+        }
+
+        private ISet IntersectDN(ISet permitted, ISet dns)
+        {
+            ISet intersect = new HashSet();
+            for (IEnumerator it = dns.GetEnumerator(); it.MoveNext(); )
+            {
+                Asn1Sequence dn = Asn1Sequence.GetInstance(((GeneralSubtree)it
+                    .Current).Base.Name.ToAsn1Object());
+                if (permitted == null)
+                {
+                    if (dn != null)
+                    {
+                        intersect.Add(dn);
+                    }
+                }
+                else
+                {
+                    IEnumerator _iter = permitted.GetEnumerator();
+                    while (_iter.MoveNext())
+                    {
+                        Asn1Sequence subtree = (Asn1Sequence)_iter.Current;
+
+                        if (WithinDNSubtree(dn, subtree))
+                        {
+                            intersect.Add(dn);
+                        }
+                        else if (WithinDNSubtree(subtree, dn))
+                        {
+                            intersect.Add(subtree);
+                        }
+                    }
+                }
+            }
+            return intersect;
+        }
+
+        private ISet UnionDN(ISet excluded, Asn1Sequence dn)
+        {
+            if (excluded.IsEmpty)
+            {
+                if (dn == null)
+                {
+                    return excluded;
+                }
+                excluded.Add(dn);
+
+                return excluded;
+            }
+            else
+            {
+                ISet intersect = new HashSet();
+
+                IEnumerator it = excluded.GetEnumerator();
+                while (it.MoveNext())
+                {
+                    Asn1Sequence subtree = (Asn1Sequence)it.Current;
+
+                    if (WithinDNSubtree(dn, subtree))
+                    {
+                        intersect.Add(subtree);
+                    }
+                    else if (WithinDNSubtree(subtree, dn))
+                    {
+                        intersect.Add(dn);
+                    }
+                    else
+                    {
+                        intersect.Add(subtree);
+                        intersect.Add(dn);
+                    }
+                }
+
+                return intersect;
+            }
+        }
+
+        private ISet IntersectEmail(ISet permitted, ISet emails)
+        {
+            ISet intersect = new HashSet();
+            for (IEnumerator it = emails.GetEnumerator(); it.MoveNext(); )
+            {
+                String email = ExtractNameAsString(((GeneralSubtree)it.Current)
+                    .Base);
+
+                if (permitted == null)
+                {
+                    if (email != null)
+                    {
+                        intersect.Add(email);
+                    }
+                }
+                else
+                {
+                    IEnumerator it2 = permitted.GetEnumerator();
+                    while (it2.MoveNext())
+                    {
+                        String _permitted = (String)it2.Current;
+
+                        intersectEmail(email, _permitted, intersect);
+                    }
+                }
+            }
+            return intersect;
+        }
+
+        private ISet UnionEmail(ISet excluded, String email)
+        {
+            if (excluded.IsEmpty)
+            {
+                if (email == null)
+                {
+                    return excluded;
+                }
+                excluded.Add(email);
+                return excluded;
+            }
+            else
+            {
+                ISet union = new HashSet();
+
+                IEnumerator it = excluded.GetEnumerator();
+                while (it.MoveNext())
+                {
+                    String _excluded = (String)it.Current;
+
+                    unionEmail(_excluded, email, union);
+                }
+
+                return union;
+            }
+        }
+
+        /**
+         * Returns the intersection of the permitted IP ranges in
+         * <code>permitted</code> with <code>ip</code>.
+         *
+         * @param permitted A <code>Set</code> of permitted IP addresses with
+         *                  their subnet mask as byte arrays.
+         * @param ips       The IP address with its subnet mask.
+         * @return The <code>Set</code> of permitted IP ranges intersected with
+         *         <code>ip</code>.
+         */
+        private ISet IntersectIP(ISet permitted, ISet ips)
+        {
+            ISet intersect = new HashSet();
+            for (IEnumerator it = ips.GetEnumerator(); it.MoveNext(); )
+            {
+                byte[] ip = Asn1OctetString.GetInstance(
+                    ((GeneralSubtree)it.Current).Base.Name).GetOctets();
+                if (permitted == null)
+                {
+                    if (ip != null)
+                    {
+                        intersect.Add(ip);
+                    }
+                }
+                else
+                {
+                    IEnumerator it2 = permitted.GetEnumerator();
+                    while (it2.MoveNext())
+                    {
+                        byte[] _permitted = (byte[])it2.Current;
+                        intersect.AddAll(IntersectIPRange(_permitted, ip));
+                    }
+                }
+            }
+            return intersect;
+        }
+
+        /**
+         * Returns the union of the excluded IP ranges in <code>excluded</code>
+         * with <code>ip</code>.
+         *
+         * @param excluded A <code>Set</code> of excluded IP addresses with their
+         *                 subnet mask as byte arrays.
+         * @param ip       The IP address with its subnet mask.
+         * @return The <code>Set</code> of excluded IP ranges unified with
+         *         <code>ip</code> as byte arrays.
+         */
+        private ISet UnionIP(ISet excluded, byte[] ip)
+        {
+            if (excluded.IsEmpty)
+            {
+                if (ip == null)
+                {
+                    return excluded;
+                }
+                excluded.Add(ip);
+
+                return excluded;
+            }
+            else
+            {
+                ISet union = new HashSet();
+
+                IEnumerator it = excluded.GetEnumerator();
+                while (it.MoveNext())
+                {
+                    byte[] _excluded = (byte[])it.Current;
+                    union.AddAll(UnionIPRange(_excluded, ip));
+                }
+
+                return union;
+            }
+        }
+
+        /**
+         * Calculates the union if two IP ranges.
+         *
+         * @param ipWithSubmask1 The first IP address with its subnet mask.
+         * @param ipWithSubmask2 The second IP address with its subnet mask.
+         * @return A <code>Set</code> with the union of both addresses.
+         */
+        private ISet UnionIPRange(byte[] ipWithSubmask1, byte[] ipWithSubmask2)
+        {
+            ISet set = new HashSet();
+
+            // difficult, adding always all IPs is not wrong
+            if (Org.BouncyCastle.Utilities.Arrays.AreEqual(ipWithSubmask1, ipWithSubmask2))
+            {
+                set.Add(ipWithSubmask1);
+            }
+            else
+            {
+                set.Add(ipWithSubmask1);
+                set.Add(ipWithSubmask2);
+            }
+            return set;
+        }
+
+        /**
+         * Calculates the interesction if two IP ranges.
+         *
+         * @param ipWithSubmask1 The first IP address with its subnet mask.
+         * @param ipWithSubmask2 The second IP address with its subnet mask.
+         * @return A <code>Set</code> with the single IP address with its subnet
+         *         mask as a byte array or an empty <code>Set</code>.
+         */
+        private ISet IntersectIPRange(byte[] ipWithSubmask1, byte[] ipWithSubmask2)
+    {
+        if (ipWithSubmask1.Length != ipWithSubmask2.Length)
+        {
+            //Collections.EMPTY_SET;
+            return new HashSet();
+        }
+
+        byte[][] temp = ExtractIPsAndSubnetMasks(ipWithSubmask1, ipWithSubmask2);
+        byte[] ip1 = temp[0];
+        byte[] subnetmask1 = temp[1];
+        byte[] ip2 = temp[2];
+        byte[] subnetmask2 = temp[3];
+
+        byte[][] minMax = MinMaxIPs(ip1, subnetmask1, ip2, subnetmask2);
+        byte[] min;
+        byte[] max;
+        max = Min(minMax[1], minMax[3]);
+        min = Max(minMax[0], minMax[2]);
+
+        // minimum IP address must be bigger than max
+        if (CompareTo(min, max) == 1)
+        {
+            //return Collections.EMPTY_SET;
+            return new HashSet();
+        }
+        // OR keeps all significant bits
+        byte[] ip = Or(minMax[0], minMax[2]);
+        byte[] subnetmask = Or(subnetmask1, subnetmask2);
+
+            //return new HashSet( ICollectionsingleton(IpWithSubnetMask(ip, subnetmask));
+        ISet hs = new HashSet();
+        hs.Add(IpWithSubnetMask(ip, subnetmask));
+
+            return hs;
+    }
+
+        /**
+         * Concatenates the IP address with its subnet mask.
+         *
+         * @param ip         The IP address.
+         * @param subnetMask Its subnet mask.
+         * @return The concatenated IP address with its subnet mask.
+         */
+        private byte[] IpWithSubnetMask(byte[] ip, byte[] subnetMask)
+        {
+            int ipLength = ip.Length;
+            byte[] temp = new byte[ipLength * 2];
+            Array.Copy(ip, 0, temp, 0, ipLength);
+            Array.Copy(subnetMask, 0, temp, ipLength, ipLength);
+            return temp;
+        }
+
+        /**
+         * Splits the IP addresses and their subnet mask.
+         *
+         * @param ipWithSubmask1 The first IP address with the subnet mask.
+         * @param ipWithSubmask2 The second IP address with the subnet mask.
+         * @return An array with two elements. Each element contains the IP address
+         *         and the subnet mask in this order.
+         */
+        private byte[][] ExtractIPsAndSubnetMasks(
+            byte[] ipWithSubmask1,
+            byte[] ipWithSubmask2)
+    {
+        int ipLength = ipWithSubmask1.Length / 2;
+        byte[] ip1 = new byte[ipLength];
+        byte[] subnetmask1 = new byte[ipLength];
+        Array.Copy(ipWithSubmask1, 0, ip1, 0, ipLength);
+        Array.Copy(ipWithSubmask1, ipLength, subnetmask1, 0, ipLength);
+
+        byte[] ip2 = new byte[ipLength];
+        byte[] subnetmask2 = new byte[ipLength];
+        Array.Copy(ipWithSubmask2, 0, ip2, 0, ipLength);
+        Array.Copy(ipWithSubmask2, ipLength, subnetmask2, 0, ipLength);
+        return new byte[][]
+            {ip1, subnetmask1, ip2, subnetmask2};
+    }
+
+        /**
+         * Based on the two IP addresses and their subnet masks the IP range is
+         * computed for each IP address - subnet mask pair and returned as the
+         * minimum IP address and the maximum address of the range.
+         *
+         * @param ip1         The first IP address.
+         * @param subnetmask1 The subnet mask of the first IP address.
+         * @param ip2         The second IP address.
+         * @param subnetmask2 The subnet mask of the second IP address.
+         * @return A array with two elements. The first/second element contains the
+         *         min and max IP address of the first/second IP address and its
+         *         subnet mask.
+         */
+        private byte[][] MinMaxIPs(
+            byte[] ip1,
+            byte[] subnetmask1,
+            byte[] ip2,
+            byte[] subnetmask2)
+        {
+            int ipLength = ip1.Length;
+            byte[] min1 = new byte[ipLength];
+            byte[] max1 = new byte[ipLength];
+
+            byte[] min2 = new byte[ipLength];
+            byte[] max2 = new byte[ipLength];
+
+            for (int i = 0; i < ipLength; i++)
+            {
+                min1[i] = (byte)(ip1[i] & subnetmask1[i]);
+                max1[i] = (byte)(ip1[i] & subnetmask1[i] | ~subnetmask1[i]);
+
+                min2[i] = (byte)(ip2[i] & subnetmask2[i]);
+                max2[i] = (byte)(ip2[i] & subnetmask2[i] | ~subnetmask2[i]);
+            }
+
+            return new byte[][] { min1, max1, min2, max2 };
+        }
+
+        private void CheckPermittedEmail(ISet permitted, String email)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (permitted == null)
+            {
+                return;
+            }
+
+            IEnumerator it = permitted.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                String str = ((String)it.Current);
+
+                if (EmailIsConstrained(email, str))
+                {
+                    return;
+                }
+            }
+
+            if (email.Length == 0 && permitted.Count == 0)
+            {
+                return;
+            }
+
+            throw new PkixNameConstraintValidatorException(
+                "Subject email address is not from a permitted subtree.");
+        }
+
+        private void CheckExcludedEmail(ISet excluded, String email)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (excluded.IsEmpty)
+            {
+                return;
+            }
+
+            IEnumerator it = excluded.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                String str = (String)it.Current;
+
+                if (EmailIsConstrained(email, str))
+                {
+                    throw new PkixNameConstraintValidatorException(
+                        "Email address is from an excluded subtree.");
+                }
+            }
+        }
+
+        /**
+         * Checks if the IP <code>ip</code> is included in the permitted ISet
+         * <code>permitted</code>.
+         *
+         * @param permitted A <code>Set</code> of permitted IP addresses with
+         *                  their subnet mask as byte arrays.
+         * @param ip        The IP address.
+         * @throws PkixNameConstraintValidatorException
+         *          if the IP is not permitted.
+         */
+        private void CheckPermittedIP(ISet permitted, byte[] ip)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (permitted == null)
+            {
+                return;
+            }
+
+            IEnumerator it = permitted.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                byte[] ipWithSubnet = (byte[])it.Current;
+
+                if (IsIPConstrained(ip, ipWithSubnet))
+                {
+                    return;
+                }
+            }
+            if (ip.Length == 0 && permitted.Count == 0)
+            {
+                return;
+            }
+            throw new PkixNameConstraintValidatorException(
+                "IP is not from a permitted subtree.");
+        }
+
+        /**
+         * Checks if the IP <code>ip</code> is included in the excluded ISet
+         * <code>excluded</code>.
+         *
+         * @param excluded A <code>Set</code> of excluded IP addresses with their
+         *                 subnet mask as byte arrays.
+         * @param ip       The IP address.
+         * @throws PkixNameConstraintValidatorException
+         *          if the IP is excluded.
+         */
+        private void checkExcludedIP(ISet excluded, byte[] ip)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (excluded.IsEmpty)
+            {
+                return;
+            }
+
+            IEnumerator it = excluded.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                byte[] ipWithSubnet = (byte[])it.Current;
+
+                if (IsIPConstrained(ip, ipWithSubnet))
+                {
+                    throw new PkixNameConstraintValidatorException(
+                        "IP is from an excluded subtree.");
+                }
+            }
+        }
+
+        /**
+         * Checks if the IP address <code>ip</code> is constrained by
+         * <code>constraint</code>.
+         *
+         * @param ip         The IP address.
+         * @param constraint The constraint. This is an IP address concatenated with
+         *                   its subnetmask.
+         * @return <code>true</code> if constrained, <code>false</code>
+         *         otherwise.
+         */
+        private bool IsIPConstrained(byte[] ip, byte[] constraint)
+        {
+            int ipLength = ip.Length;
+
+            if (ipLength != (constraint.Length / 2))
+            {
+                return false;
+            }
+
+            byte[] subnetMask = new byte[ipLength];
+            Array.Copy(constraint, ipLength, subnetMask, 0, ipLength);
+
+            byte[] permittedSubnetAddress = new byte[ipLength];
+
+            byte[] ipSubnetAddress = new byte[ipLength];
+
+            // the resulting IP address by applying the subnet mask
+            for (int i = 0; i < ipLength; i++)
+            {
+                permittedSubnetAddress[i] = (byte)(constraint[i] & subnetMask[i]);
+                ipSubnetAddress[i] = (byte)(ip[i] & subnetMask[i]);
+            }
+
+            return Org.BouncyCastle.Utilities.Arrays.AreEqual(permittedSubnetAddress, ipSubnetAddress);
+        }
+
+        private bool EmailIsConstrained(String email, String constraint)
+        {
+            String sub = email.Substring(email.IndexOf('@') + 1);
+            // a particular mailbox
+            if (constraint.IndexOf('@') != -1)
+            {
+                if (email.ToUpper().Equals(constraint.ToUpper()))
+                {
+                    return true;
+                }
+            }
+            // on particular host
+            else if (!(constraint[0].Equals('.')))
+            {
+                if (sub.ToUpper().Equals(constraint.ToUpper()))
+                {
+                    return true;
+                }
+            }
+            // address in sub domain
+            else if (WithinDomain(sub, constraint))
+            {
+                return true;
+            }
+            return false;
+        }
+
+        private bool WithinDomain(String testDomain, String domain)
+        {
+            String tempDomain = domain;
+            if (tempDomain.StartsWith("."))
+            {
+                tempDomain = tempDomain.Substring(1);
+            }
+            String[] domainParts = tempDomain.Split('.'); // Strings.split(tempDomain, '.');
+            String[] testDomainParts = testDomain.Split('.'); // Strings.split(testDomain, '.');
+
+            // must have at least one subdomain
+            if (testDomainParts.Length <= domainParts.Length)
+            {
+                return false;
+            }
+
+            int d = testDomainParts.Length - domainParts.Length;
+            for (int i = -1; i < domainParts.Length; i++)
+            {
+                if (i == -1)
+                {
+                    if (testDomainParts[i + d].Equals(""))
+                    {
+                        return false;
+                    }
+                }
+                else if (!(Platform.CompareIgnoreCase(testDomainParts[i + d], domainParts[i]) == 0))
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        private void CheckPermittedDNS(ISet permitted, String dns)
+        //throws PkixNameConstraintValidatorException
+        {
+            if (permitted == null)
+            {
+                return;
+            }
+
+            IEnumerator it = permitted.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                String str = ((String)it.Current);
+
+                // is sub domain
+                if (WithinDomain(dns, str) || dns.ToUpper().Equals(str.ToUpper()))
+                {
+                    return;
+                }
+            }
+            if (dns.Length == 0 && permitted.Count == 0)
+            {
+                return;
+            }
+            throw new PkixNameConstraintValidatorException(
+                "DNS is not from a permitted subtree.");
+        }
+
+        private void checkExcludedDNS(ISet excluded, String dns)
+        //     throws PkixNameConstraintValidatorException
+        {
+            if (excluded.IsEmpty)
+            {
+                return;
+            }
+
+            IEnumerator it = excluded.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                String str = ((String)it.Current);
+
+                // is sub domain or the same
+				if (WithinDomain(dns, str) || (Platform.CompareIgnoreCase(dns, str) == 0))
+                {
+                    throw new PkixNameConstraintValidatorException(
+                        "DNS is from an excluded subtree.");
+                }
+            }
+        }
+
+        /**
+         * The common part of <code>email1</code> and <code>email2</code> is
+         * added to the union <code>union</code>. If <code>email1</code> and
+         * <code>email2</code> have nothing in common they are added both.
+         *
+         * @param email1 Email address constraint 1.
+         * @param email2 Email address constraint 2.
+         * @param union  The union.
+         */
+        private void unionEmail(String email1, String email2, ISet union)
+        {
+            // email1 is a particular address
+            if (email1.IndexOf('@') != -1)
+            {
+                String _sub = email1.Substring(email1.IndexOf('@') + 1);
+                // both are a particular mailbox
+                if (email2.IndexOf('@') != -1)
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(_sub, email2))
+                    {
+                        union.Add(email2);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(_sub, email2) == 0)
+                    {
+                        union.Add(email2);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+            }
+            // email1 specifies a domain
+            else if (email1.StartsWith("."))
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email1.IndexOf('@') + 1);
+                    if (WithinDomain(_sub, email1))
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2) || Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        union.Add(email2);
+                    }
+                    else if (WithinDomain(email2, email1))
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                else
+                {
+                    if (WithinDomain(email2, email1))
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+            }
+            // email specifies a host
+            else
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email1.IndexOf('@') + 1);
+                    if (Platform.CompareIgnoreCase(_sub, email1) == 0)
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2))
+                    {
+                        union.Add(email2);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+            }
+        }
+
+        private void unionURI(String email1, String email2, ISet union)
+        {
+            // email1 is a particular address
+            if (email1.IndexOf('@') != -1)
+            {
+                String _sub = email1.Substring(email1.IndexOf('@') + 1);
+                // both are a particular mailbox
+                if (email2.IndexOf('@') != -1)
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(_sub, email2))
+                    {
+                        union.Add(email2);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(_sub, email2) == 0)
+                    {
+                        union.Add(email2);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+
+                    }
+                }
+            }
+            // email1 specifies a domain
+            else if (email1.StartsWith("."))
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email1.IndexOf('@') + 1);
+                    if (WithinDomain(_sub, email1))
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2) || Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        union.Add(email2);
+                    }
+                    else if (WithinDomain(email2, email1))
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                else
+                {
+                    if (WithinDomain(email2, email1))
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+            }
+            // email specifies a host
+            else
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email1.IndexOf('@') + 1);
+                    if (Platform.CompareIgnoreCase(_sub, email1) == 0)
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2))
+                    {
+                        union.Add(email2);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        union.Add(email1);
+                    }
+                    else
+                    {
+                        union.Add(email1);
+                        union.Add(email2);
+                    }
+                }
+            }
+        }
+
+        private ISet intersectDNS(ISet permitted, ISet dnss)
+        {
+            ISet intersect = new HashSet();
+            for (IEnumerator it = dnss.GetEnumerator(); it.MoveNext(); )
+            {
+                String dns = ExtractNameAsString(((GeneralSubtree)it.Current)
+                    .Base);
+                if (permitted == null)
+                {
+                    if (dns != null)
+                    {
+                        intersect.Add(dns);
+                    }
+                }
+                else
+                {
+                    IEnumerator _iter = permitted.GetEnumerator();
+                    while (_iter.MoveNext())
+                    {
+                        String _permitted = (String)_iter.Current;
+
+                        if (WithinDomain(_permitted, dns))
+                        {
+                            intersect.Add(_permitted);
+                        }
+                        else if (WithinDomain(dns, _permitted))
+                        {
+                            intersect.Add(dns);
+                        }
+                    }
+                }
+            }
+
+            return intersect;
+        }
+
+        protected ISet unionDNS(ISet excluded, String dns)
+        {
+            if (excluded.IsEmpty)
+            {
+                if (dns == null)
+                {
+                    return excluded;
+                }
+                excluded.Add(dns);
+
+                return excluded;
+            }
+            else
+            {
+                ISet union = new HashSet();
+
+                IEnumerator _iter = excluded.GetEnumerator();
+                while (_iter.MoveNext())
+                {
+                    String _permitted = (String)_iter.Current;
+
+                    if (WithinDomain(_permitted, dns))
+                    {
+                        union.Add(dns);
+                    }
+                    else if (WithinDomain(dns, _permitted))
+                    {
+                        union.Add(_permitted);
+                    }
+                    else
+                    {
+                        union.Add(_permitted);
+                        union.Add(dns);
+                    }
+                }
+
+                return union;
+            }
+        }
+
+        /**
+         * The most restricting part from <code>email1</code> and
+         * <code>email2</code> is added to the intersection <code>intersect</code>.
+         *
+         * @param email1    Email address constraint 1.
+         * @param email2    Email address constraint 2.
+         * @param intersect The intersection.
+         */
+        private void intersectEmail(String email1, String email2, ISet intersect)
+        {
+            // email1 is a particular address
+            if (email1.IndexOf('@') != -1)
+            {
+                String _sub = email1.Substring(email1.IndexOf('@') + 1);
+                // both are a particular mailbox
+                if (email2.IndexOf('@') != -1)
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(_sub, email2))
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(_sub, email2) == 0)
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+            }
+            // email specifies a domain
+            else if (email1.StartsWith("."))
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email1.IndexOf('@') + 1);
+                    if (WithinDomain(_sub, email1))
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2) || (Platform.CompareIgnoreCase(email1, email2) == 0))
+                    {
+                        intersect.Add(email1);
+                    }
+                    else if (WithinDomain(email2, email1))
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+                else
+                {
+                    if (WithinDomain(email2, email1))
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+            }
+            // email1 specifies a host
+            else
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email2.IndexOf('@') + 1);
+                    if (Platform.CompareIgnoreCase(_sub, email1) == 0)
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2))
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+            }
+        }
+
+        private void checkExcludedURI(ISet excluded, String uri)
+        //       throws PkixNameConstraintValidatorException
+        {
+            if (excluded.IsEmpty)
+            {
+                return;
+            }
+
+            IEnumerator it = excluded.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                String str = ((String)it.Current);
+
+                if (IsUriConstrained(uri, str))
+                {
+                    throw new PkixNameConstraintValidatorException(
+                        "URI is from an excluded subtree.");
+                }
+            }
+        }
+
+        private ISet intersectURI(ISet permitted, ISet uris)
+        {
+            ISet intersect = new HashSet();
+            for (IEnumerator it = uris.GetEnumerator(); it.MoveNext(); )
+            {
+                String uri = ExtractNameAsString(((GeneralSubtree)it.Current)
+                    .Base);
+                if (permitted == null)
+                {
+                    if (uri != null)
+                    {
+                        intersect.Add(uri);
+                    }
+                }
+                else
+                {
+                    IEnumerator _iter = permitted.GetEnumerator();
+                    while (_iter.MoveNext())
+                    {
+                        String _permitted = (String)_iter.Current;
+                        intersectURI(_permitted, uri, intersect);
+                    }
+                }
+            }
+            return intersect;
+        }
+
+        private ISet unionURI(ISet excluded, String uri)
+        {
+            if (excluded.IsEmpty)
+            {
+                if (uri == null)
+                {
+                    return excluded;
+                }
+                excluded.Add(uri);
+
+                return excluded;
+            }
+            else
+            {
+                ISet union = new HashSet();
+
+                IEnumerator _iter = excluded.GetEnumerator();
+                while (_iter.MoveNext())
+                {
+                    String _excluded = (String)_iter.Current;
+
+                    unionURI(_excluded, uri, union);
+                }
+
+                return union;
+            }
+        }
+
+        private void intersectURI(String email1, String email2, ISet intersect)
+        {
+            // email1 is a particular address
+            if (email1.IndexOf('@') != -1)
+            {
+                String _sub = email1.Substring(email1.IndexOf('@') + 1);
+                // both are a particular mailbox
+                if (email2.IndexOf('@') != -1)
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(_sub, email2))
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(_sub, email2) == 0)
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+            }
+            // email specifies a domain
+            else if (email1.StartsWith("."))
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email1.IndexOf('@') + 1);
+                    if (WithinDomain(_sub, email1))
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2) || (Platform.CompareIgnoreCase(email1, email2) == 0))
+                    {
+                        intersect.Add(email1);
+                    }
+                    else if (WithinDomain(email2, email1))
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+                else
+                {
+                    if (WithinDomain(email2, email1))
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+            }
+            // email1 specifies a host
+            else
+            {
+                if (email2.IndexOf('@') != -1)
+                {
+                    String _sub = email2.Substring(email2.IndexOf('@') + 1);
+                    if (Platform.CompareIgnoreCase(_sub, email1) == 0)
+                    {
+                        intersect.Add(email2);
+                    }
+                }
+                // email2 specifies a domain
+                else if (email2.StartsWith("."))
+                {
+                    if (WithinDomain(email1, email2))
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+                // email2 specifies a particular host
+                else
+                {
+                    if (Platform.CompareIgnoreCase(email1, email2) == 0)
+                    {
+                        intersect.Add(email1);
+                    }
+                }
+            }
+        }
+
+        private void CheckPermittedURI(ISet permitted, String uri)
+        //        throws PkixNameConstraintValidatorException
+        {
+            if (permitted == null)
+            {
+                return;
+            }
+
+            IEnumerator it = permitted.GetEnumerator();
+
+            while (it.MoveNext())
+            {
+                String str = ((String)it.Current);
+
+                if (IsUriConstrained(uri, str))
+                {
+                    return;
+                }
+            }
+            if (uri.Length == 0 && permitted.Count == 0)
+            {
+                return;
+            }
+            throw new PkixNameConstraintValidatorException(
+                "URI is not from a permitted subtree.");
+        }
+
+        private bool IsUriConstrained(String uri, String constraint)
+        {
+            String host = ExtractHostFromURL(uri);
+            // a host
+            if (!constraint.StartsWith("."))
+            {
+                if (Platform.CompareIgnoreCase(host, constraint) == 0)
+                {
+                    return true;
+                }
+            }
+
+            // in sub domain or domain
+            else if (WithinDomain(host, constraint))
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        private static String ExtractHostFromURL(String url)
+        {
+            // see RFC 1738
+            // remove ':' after protocol, e.g. http:
+            String sub = url.Substring(url.IndexOf(':') + 1);
+            // extract host from Common Internet Scheme Syntax, e.g. http://
+            if (sub.IndexOf("//") != -1)
+            {
+                sub = sub.Substring(sub.IndexOf("//") + 2);
+            }
+            // first remove port, e.g. http://test.com:21
+            if (sub.LastIndexOf(':') != -1)
+            {
+                sub = sub.Substring(0, sub.LastIndexOf(':'));
+            }
+            // remove user and password, e.g. http://john:password@test.com
+            sub = sub.Substring(sub.IndexOf(':') + 1);
+            sub = sub.Substring(sub.IndexOf('@') + 1);
+            // remove local parts, e.g. http://test.com/bla
+            if (sub.IndexOf('/') != -1)
+            {
+                sub = sub.Substring(0, sub.IndexOf('/'));
+            }
+            return sub;
+        }
+
+        /**
+         * Checks if the given GeneralName is in the permitted ISet.
+         *
+         * @param name The GeneralName
+         * @throws PkixNameConstraintValidatorException
+         *          If the <code>name</code>
+         */
+        public void checkPermitted(GeneralName name)
+        //        throws PkixNameConstraintValidatorException
+        {
+            switch (name.TagNo)
+            {
+                case 1:
+                    CheckPermittedEmail(permittedSubtreesEmail,
+                        ExtractNameAsString(name));
+                    break;
+                case 2:
+                    CheckPermittedDNS(permittedSubtreesDNS, DerIA5String.GetInstance(
+                        name.Name).GetString());
+                    break;
+                case 4:
+                    CheckPermittedDN(Asn1Sequence.GetInstance(name.Name.ToAsn1Object()));
+                    break;
+                case 6:
+                    CheckPermittedURI(permittedSubtreesURI, DerIA5String.GetInstance(
+                        name.Name).GetString());
+                    break;
+                case 7:
+                    byte[] ip = Asn1OctetString.GetInstance(name.Name).GetOctets();
+
+                    CheckPermittedIP(permittedSubtreesIP, ip);
+                    break;
+            }
+        }
+
+        /**
+         * Check if the given GeneralName is contained in the excluded ISet.
+         *
+         * @param name The GeneralName.
+         * @throws PkixNameConstraintValidatorException
+         *          If the <code>name</code> is
+         *          excluded.
+         */
+        public void checkExcluded(GeneralName name)
+        //        throws PkixNameConstraintValidatorException
+        {
+            switch (name.TagNo)
+            {
+                case 1:
+                    CheckExcludedEmail(excludedSubtreesEmail, ExtractNameAsString(name));
+                    break;
+                case 2:
+                    checkExcludedDNS(excludedSubtreesDNS, DerIA5String.GetInstance(
+                        name.Name).GetString());
+                    break;
+                case 4:
+                    CheckExcludedDN(Asn1Sequence.GetInstance(name.Name.ToAsn1Object()));
+                    break;
+                case 6:
+                    checkExcludedURI(excludedSubtreesURI, DerIA5String.GetInstance(
+                        name.Name).GetString());
+                    break;
+                case 7:
+                    byte[] ip = Asn1OctetString.GetInstance(name.Name).GetOctets();
+
+                    checkExcludedIP(excludedSubtreesIP, ip);
+                    break;
+            }
+        }
+
+        /**
+         * Updates the permitted ISet of these name constraints with the intersection
+         * with the given subtree.
+         *
+         * @param permitted The permitted subtrees
+         */
+
+        public void IntersectPermittedSubtree(Asn1Sequence permitted)
+        {
+            IDictionary subtreesMap = Platform.CreateHashtable();
+
+            // group in ISets in a map ordered by tag no.
+            for (IEnumerator e = permitted.GetEnumerator(); e.MoveNext(); )
+            {
+                GeneralSubtree subtree = GeneralSubtree.GetInstance(e.Current);
+
+                int tagNo = subtree.Base.TagNo;
+                if (subtreesMap[tagNo] == null)
+                {
+                    subtreesMap[tagNo] = new HashSet();
+                }
+
+                ((ISet)subtreesMap[tagNo]).Add(subtree);
+            }
+
+            for (IEnumerator it = subtreesMap.GetEnumerator(); it.MoveNext(); )
+            {
+                DictionaryEntry entry = (DictionaryEntry)it.Current;
+
+                // go through all subtree groups
+                switch ((int)entry.Key )
+                {
+                    case 1:
+                        permittedSubtreesEmail = IntersectEmail(permittedSubtreesEmail,
+                            (ISet)entry.Value);
+                        break;
+                    case 2:
+                        permittedSubtreesDNS = intersectDNS(permittedSubtreesDNS,
+                            (ISet)entry.Value);
+                        break;
+                    case 4:
+                        permittedSubtreesDN = IntersectDN(permittedSubtreesDN,
+                            (ISet)entry.Value);
+                        break;
+                    case 6:
+                        permittedSubtreesURI = intersectURI(permittedSubtreesURI,
+                            (ISet)entry.Value);
+                        break;
+                    case 7:
+                        permittedSubtreesIP = IntersectIP(permittedSubtreesIP,
+                            (ISet)entry.Value);
+                        break;
+                }
+            }
+        }
+
+        private String ExtractNameAsString(GeneralName name)
+        {
+            return DerIA5String.GetInstance(name.Name).GetString();
+        }
+
+        public void IntersectEmptyPermittedSubtree(int nameType)
+        {
+            switch (nameType)
+            {
+                case 1:
+                    permittedSubtreesEmail = new HashSet();
+                    break;
+                case 2:
+                    permittedSubtreesDNS = new HashSet();
+                    break;
+                case 4:
+                    permittedSubtreesDN = new HashSet();
+                    break;
+                case 6:
+                    permittedSubtreesURI = new HashSet();
+                    break;
+                case 7:
+                    permittedSubtreesIP = new HashSet();
+                    break;
+            }
+        }
+
+        /**
+         * Adds a subtree to the excluded ISet of these name constraints.
+         *
+         * @param subtree A subtree with an excluded GeneralName.
+         */
+        public void AddExcludedSubtree(GeneralSubtree subtree)
+        {
+            GeneralName subTreeBase = subtree.Base;
+
+            switch (subTreeBase.TagNo)
+            {
+                case 1:
+                    excludedSubtreesEmail = UnionEmail(excludedSubtreesEmail,
+                        ExtractNameAsString(subTreeBase));
+                    break;
+                case 2:
+                    excludedSubtreesDNS = unionDNS(excludedSubtreesDNS,
+                        ExtractNameAsString(subTreeBase));
+                    break;
+                case 4:
+                    excludedSubtreesDN = UnionDN(excludedSubtreesDN,
+                        (Asn1Sequence)subTreeBase.Name.ToAsn1Object());
+                    break;
+                case 6:
+                    excludedSubtreesURI = unionURI(excludedSubtreesURI,
+                        ExtractNameAsString(subTreeBase));
+                    break;
+                case 7:
+                    excludedSubtreesIP = UnionIP(excludedSubtreesIP, Asn1OctetString
+                        .GetInstance(subTreeBase.Name).GetOctets());
+                    break;
+            }
+        }
+
+        /**
+         * Returns the maximum IP address.
+         *
+         * @param ip1 The first IP address.
+         * @param ip2 The second IP address.
+         * @return The maximum IP address.
+         */
+        private static byte[] Max(byte[] ip1, byte[] ip2)
+        {
+            for (int i = 0; i < ip1.Length; i++)
+            {
+                if ((ip1[i] & 0xFFFF) > (ip2[i] & 0xFFFF))
+                {
+                    return ip1;
+                }
+            }
+            return ip2;
+        }
+
+        /**
+         * Returns the minimum IP address.
+         *
+         * @param ip1 The first IP address.
+         * @param ip2 The second IP address.
+         * @return The minimum IP address.
+         */
+        private static byte[] Min(byte[] ip1, byte[] ip2)
+        {
+            for (int i = 0; i < ip1.Length; i++)
+            {
+                if ((ip1[i] & 0xFFFF) < (ip2[i] & 0xFFFF))
+                {
+                    return ip1;
+                }
+            }
+            return ip2;
+        }
+
+        /**
+         * Compares IP address <code>ip1</code> with <code>ip2</code>. If ip1
+         * is equal to ip2 0 is returned. If ip1 is bigger 1 is returned, -1
+         * otherwise.
+         *
+         * @param ip1 The first IP address.
+         * @param ip2 The second IP address.
+         * @return 0 if ip1 is equal to ip2, 1 if ip1 is bigger, -1 otherwise.
+         */
+        private static int CompareTo(byte[] ip1, byte[] ip2)
+        {
+            if (Org.BouncyCastle.Utilities.Arrays.AreEqual(ip1, ip2))
+            {
+                return 0;
+            }
+            if (Org.BouncyCastle.Utilities.Arrays.AreEqual(Max(ip1, ip2), ip1))
+            {
+                return 1;
+            }
+            return -1;
+        }
+
+        /**
+         * Returns the logical OR of the IP addresses <code>ip1</code> and
+         * <code>ip2</code>.
+         *
+         * @param ip1 The first IP address.
+         * @param ip2 The second IP address.
+         * @return The OR of <code>ip1</code> and <code>ip2</code>.
+         */
+        private static byte[] Or(byte[] ip1, byte[] ip2)
+        {
+            byte[] temp = new byte[ip1.Length];
+            for (int i = 0; i < ip1.Length; i++)
+            {
+                temp[i] = (byte)(ip1[i] | ip2[i]);
+            }
+            return temp;
+        }
+
+		[Obsolete("Use GetHashCode instead")]
+		public int HashCode()
+		{
+			return GetHashCode();
+		}
+
+		public override int GetHashCode()
+        {
+            return HashCollection(excludedSubtreesDN)
+                + HashCollection(excludedSubtreesDNS)
+                + HashCollection(excludedSubtreesEmail)
+                + HashCollection(excludedSubtreesIP)
+                + HashCollection(excludedSubtreesURI)
+                + HashCollection(permittedSubtreesDN)
+                + HashCollection(permittedSubtreesDNS)
+                + HashCollection(permittedSubtreesEmail)
+                + HashCollection(permittedSubtreesIP)
+                + HashCollection(permittedSubtreesURI);
+        }
+
+        private int HashCollection(ICollection coll)
+        {
+            if (coll == null)
+            {
+                return 0;
+            }
+            int hash = 0;
+            IEnumerator it1 = coll.GetEnumerator();
+            while (it1.MoveNext())
+            {
+                Object o = it1.Current;
+                if (o is byte[])
+                {
+                    hash += Org.BouncyCastle.Utilities.Arrays.GetHashCode((byte[])o);
+                }
+                else
+                {
+                    hash += o.GetHashCode();
+                }
+            }
+            return hash;
+        }
+
+		public override bool Equals(Object o)
+		{
+			if (!(o is PkixNameConstraintValidator))
+				return false;
+
+			PkixNameConstraintValidator constraintValidator = (PkixNameConstraintValidator)o;
+
+			return CollectionsAreEqual(constraintValidator.excludedSubtreesDN, excludedSubtreesDN)
+				&& CollectionsAreEqual(constraintValidator.excludedSubtreesDNS, excludedSubtreesDNS)
+				&& CollectionsAreEqual(constraintValidator.excludedSubtreesEmail, excludedSubtreesEmail)
+				&& CollectionsAreEqual(constraintValidator.excludedSubtreesIP, excludedSubtreesIP)
+				&& CollectionsAreEqual(constraintValidator.excludedSubtreesURI, excludedSubtreesURI)
+				&& CollectionsAreEqual(constraintValidator.permittedSubtreesDN, permittedSubtreesDN)
+				&& CollectionsAreEqual(constraintValidator.permittedSubtreesDNS, permittedSubtreesDNS)
+				&& CollectionsAreEqual(constraintValidator.permittedSubtreesEmail, permittedSubtreesEmail)
+				&& CollectionsAreEqual(constraintValidator.permittedSubtreesIP, permittedSubtreesIP)
+				&& CollectionsAreEqual(constraintValidator.permittedSubtreesURI, permittedSubtreesURI);
+		}
+
+        private bool CollectionsAreEqual(ICollection coll1, ICollection coll2)
+        {
+            if (coll1 == coll2)
+            {
+                return true;
+            }
+            if (coll1 == null || coll2 == null)
+            {
+                return false;
+            }
+            if (coll1.Count != coll2.Count)
+            {
+                return false;
+            }
+            IEnumerator it1 = coll1.GetEnumerator();
+
+            while (it1.MoveNext())
+            {
+                Object a = it1.Current;
+                IEnumerator it2 = coll2.GetEnumerator();
+                bool found = false;
+                while (it2.MoveNext())
+                {
+                    Object b = it2.Current;
+                    if (SpecialEquals(a, b))
+                    {
+                        found = true;
+                        break;
+                    }
+                }
+                if (!found)
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        private bool SpecialEquals(Object o1, Object o2)
+        {
+            if (o1 == o2)
+            {
+                return true;
+            }
+            if (o1 == null || o2 == null)
+            {
+                return false;
+            }
+            if ((o1 is byte[]) && (o2 is byte[]))
+            {
+                return Org.BouncyCastle.Utilities.Arrays.AreEqual((byte[])o1, (byte[])o2);
+            }
+            else
+            {
+                return o1.Equals(o2);
+            }
+        }
+
+        /**
+         * Stringifies an IPv4 or v6 address with subnet mask.
+         *
+         * @param ip The IP with subnet mask.
+         * @return The stringified IP address.
+         */
+        private String StringifyIP(byte[] ip)
+        {
+            String temp = "";
+            for (int i = 0; i < ip.Length / 2; i++)
+            {
+                //temp += Integer.toString(ip[i] & 0x00FF) + ".";
+                temp += (ip[i] & 0x00FF) + ".";
+            }
+            temp = temp.Substring(0, temp.Length - 1);
+            temp += "/";
+            for (int i = ip.Length / 2; i < ip.Length; i++)
+            {
+                //temp += Integer.toString(ip[i] & 0x00FF) + ".";
+                temp += (ip[i] & 0x00FF) + ".";
+            }
+            temp = temp.Substring(0, temp.Length - 1);
+            return temp;
+        }
+
+        private String StringifyIPCollection(ISet ips)
+        {
+            String temp = "";
+            temp += "[";
+            for (IEnumerator it = ips.GetEnumerator(); it.MoveNext(); )
+            {
+                temp += StringifyIP((byte[])it.Current) + ",";
+            }
+            if (temp.Length > 1)
+            {
+                temp = temp.Substring(0, temp.Length - 1);
+            }
+            temp += "]";
+
+            return temp;
+        }
+
+        public override String ToString()
+        {
+            String temp = "";
+
+            temp += "permitted:\n";
+            if (permittedSubtreesDN != null)
+            {
+                temp += "DN:\n";
+                temp += permittedSubtreesDN.ToString() + "\n";
+            }
+            if (permittedSubtreesDNS != null)
+            {
+                temp += "DNS:\n";
+                temp += permittedSubtreesDNS.ToString() + "\n";
+            }
+            if (permittedSubtreesEmail != null)
+            {
+                temp += "Email:\n";
+                temp += permittedSubtreesEmail.ToString() + "\n";
+            }
+            if (permittedSubtreesURI != null)
+            {
+                temp += "URI:\n";
+                temp += permittedSubtreesURI.ToString() + "\n";
+            }
+            if (permittedSubtreesIP != null)
+            {
+                temp += "IP:\n";
+                temp += StringifyIPCollection(permittedSubtreesIP) + "\n";
+            }
+            temp += "excluded:\n";
+            if (!(excludedSubtreesDN.IsEmpty))
+            {
+                temp += "DN:\n";
+                temp += excludedSubtreesDN.ToString() + "\n";
+            }
+            if (!excludedSubtreesDNS.IsEmpty)
+            {
+                temp += "DNS:\n";
+                temp += excludedSubtreesDNS.ToString() + "\n";
+            }
+            if (!excludedSubtreesEmail.IsEmpty)
+            {
+                temp += "Email:\n";
+                temp += excludedSubtreesEmail.ToString() + "\n";
+            }
+            if (!excludedSubtreesURI.IsEmpty)
+            {
+                temp += "URI:\n";
+                temp += excludedSubtreesURI.ToString() + "\n";
+            }
+            if (!excludedSubtreesIP.IsEmpty)
+            {
+                temp += "IP:\n";
+                temp += StringifyIPCollection(excludedSubtreesIP) + "\n";
+            }
+            return temp;
+        }
+
+    }
+}