TLSharp/TLSharp.Core/MTProto/Crypto/AuthKey.cs

using System;
using System.IO;
using System.Security.Cryptography;

namespace TLSharp.Core.MTProto.Crypto {
    public class AuthKey {
        private byte[] key;
        private ulong keyId;
        private ulong auxHash;
        public AuthKey(BigInteger gab) {
            key = gab.ToByteArrayUnsigned();
            using(SHA1 hash = new SHA1Managed()) {
                using(MemoryStream hashStream = new MemoryStream(hash.ComputeHash(key), false)) {
                    using(BinaryReader hashReader = new BinaryReader(hashStream)) {
                        auxHash = hashReader.ReadUInt64();
                        hashReader.ReadBytes(4);
                        keyId = hashReader.ReadUInt64();
                    }
                }
            }
        }

        public AuthKey(byte[] data) {
            key = data;
            using (SHA1 hash = new SHA1Managed()) {
                using (MemoryStream hashStream = new MemoryStream(hash.ComputeHash(key), false)) {
                    using (BinaryReader hashReader = new BinaryReader(hashStream)) {
                        auxHash = hashReader.ReadUInt64();
                        hashReader.ReadBytes(4);
                        keyId = hashReader.ReadUInt64();
                    }
                }
            }
        }

        public byte[] CalcNewNonceHash(byte[] newNonce, int number) {
            using(MemoryStream buffer = new MemoryStream(100)) {
                using(BinaryWriter bufferWriter = new BinaryWriter(buffer)) {
                    bufferWriter.Write(newNonce);
                    bufferWriter.Write((byte)number);
                    bufferWriter.Write(auxHash);
                    using(SHA1 sha1 = new SHA1Managed()) {
                        byte[] hash = sha1.ComputeHash(buffer.GetBuffer(), 0, (int)buffer.Position);
                        byte[] newNonceHash = new byte[16];
                        Array.Copy(hash, 4, newNonceHash, 0, 16);
                        return newNonceHash;
                    }
                }
            }
        }

        public byte[] Data {
            get {
                return key;
            }
        }

        public ulong Id {
            get {
                return keyId;
            }
        }

        public override string ToString() {
            return string.Format("(Key: {0}, KeyId: {1}, AuxHash: {2})", key, keyId, auxHash);
        }
    }
}