# < Summary

Information

Class: | Renci.SshNet.Security.KeyExchangeDiffieHellman
Assembly: | Renci.SshNet
File(s): | \home\appveyor\projects\ssh-net\src\Renci.SshNet\Security\KeyExchangeDiffieHellman.cs

Line coverage
86%

Covered lines: | 25
Uncovered lines: | 4
Coverable lines: | 29
Total lines: | 140
Line coverage: | 86.2%

Branch coverage
62%

Covered branches: | 5
Total branches: | 8
Branch coverage: | 62.5%

Method coverage

Feature is only available for sponsors

Upgrade to PRO version

# Metrics

Method | Branch coverage | Cyclomatic complexity | Line coverage
--- | --- | --- | ---
ValidateExchangeHash() | 100% | 1 | 100%
Start(...) | 100% | 1 | 100%
PopulateClientExchangeValue() | 62.5% | 8 | 73.33%
HandleServerDhReply(...) | 100% | 1 | 100%

# File(s)

## \home\appveyor\projects\ssh-net\src\Renci.SshNet\Security\KeyExchangeDiffieHellman.cs

| # | Line |  | Line coverage
--- | --- | --- | --- | ---
|  | `1` |  | `using System;`
|  | `2` |  | ``
|  | `3` |  | `using Renci.SshNet.Common;`
|  | `4` |  | `using Renci.SshNet.Messages.Transport;`
|  | `5` |  | ``
|  | `6` |  | `namespace Renci.SshNet.Security`
|  | `7` |  | `{`
|  | `8` |  | `/// <summary>`
|  | `9` |  | `/// Represents base class for Diffie Hellman key exchange algorithm.`
|  | `10` |  | `/// </summary>`
|  | `11` |  | `internal abstract class KeyExchangeDiffieHellman : KeyExchange`
|  | `12` |  | `{`
|  | `13` |  | `#pragma warning disable SA1401 // Fields should be private`
|  | `14` |  | `/// <summary>`
|  | `15` |  | `/// Specifies key exchange group number.`
|  | `16` |  | `/// </summary>`
|  | `17` |  | `protected BigInteger _group;`
|  | `18` |  | ``
|  | `19` |  | `/// <summary>`
|  | `20` |  | `/// Specifies key exchange prime number.`
|  | `21` |  | `/// </summary>`
|  | `22` |  | `protected BigInteger _prime;`
|  | `23` |  | ``
|  | `24` |  | `/// <summary>`
|  | `25` |  | `/// Specifies client payload.`
|  | `26` |  | `/// </summary>`
|  | `27` |  | `protected byte[] _clientPayload;`
|  | `28` |  | ``
|  | `29` |  | `/// <summary>`
|  | `30` |  | `/// Specifies server payload.`
|  | `31` |  | `/// </summary>`
|  | `32` |  | `protected byte[] _serverPayload;`
|  | `33` |  | ``
|  | `34` |  | `/// <summary>`
|  | `35` |  | `/// Specifies client exchange number.`
|  | `36` |  | `/// </summary>`
|  | `37` |  | `protected byte[] _clientExchangeValue;`
|  | `38` |  | ``
|  | `39` |  | `/// <summary>`
|  | `40` |  | `/// Specifies server exchange number.`
|  | `41` |  | `/// </summary>`
|  | `42` |  | `protected byte[] _serverExchangeValue;`
|  | `43` |  | ``
|  | `44` |  | `/// <summary>`
|  | `45` |  | `/// Specifies random generated number.`
|  | `46` |  | `/// </summary>`
|  | `47` |  | `protected BigInteger _privateExponent;`
|  | `48` |  | ``
|  | `49` |  | `/// <summary>`
|  | `50` |  | `/// Specifies host key data.`
|  | `51` |  | `/// </summary>`
|  | `52` |  | `protected byte[] _hostKey;`
|  | `53` |  | ``
|  | `54` |  | `/// <summary>`
|  | `55` |  | `/// Specifies signature data.`
|  | `56` |  | `/// </summary>`
|  | `57` |  | `protected byte[] _signature;`
|  | `58` |  | `#pragma warning restore SA1401 // Fields should be private`
|  | `59` |  | ``
|  | `60` |  | `/// <summary>`
|  | `61` |  | `/// Gets the size, in bits, of the computed hash code.`
|  | `62` |  | `/// </summary>`
|  | `63` |  | `/// <value>`
|  | `64` |  | `/// The size, in bits, of the computed hash code.`
|  | `65` |  | `/// </value>`
|  | `66` |  | `protected abstract int HashSize { get; }`
|  | `67` |  | ``
|  | `68` |  | `/// <summary>`
|  | `69` |  | `/// Validates the exchange hash.`
|  | `70` |  | `/// </summary>`
|  | `71` |  | `/// <returns>`
|  | `72` |  | `/// true if exchange hash is valid; otherwise false.`
|  | `73` |  | `/// </returns>`
|  | `74` |  | `protected override bool ValidateExchangeHash()`
| 18 | `75` |  | `{`
| 18 | `76` |  | `return ValidateExchangeHash(_hostKey, _signature);`
| 18 | `77` |  | `}`
|  | `78` |  | ``
|  | `79` |  | `/// <summary>`
|  | `80` |  | `/// Starts key exchange algorithm.`
|  | `81` |  | `/// </summary>`
|  | `82` |  | `/// <param name="session">The session.</param>`
|  | `83` |  | `/// <param name="message">Key exchange init message.</param>`
|  | `84` |  | `public override void Start(Session session, KeyExchangeInitMessage message)`
| 18 | `85` |  | `{`
| 18 | `86` |  | `base.Start(session, message);`
|  | `87` |  | ``
| 18 | `88` |  | `_serverPayload = message.GetBytes();`
| 18 | `89` |  | `_clientPayload = Session.ClientInitMessage.GetBytes();`
| 18 | `90` |  | `}`
|  | `91` |  | ``
|  | `92` |  | `/// <summary>`
|  | `93` |  | `/// Populates the client exchange value.`
|  | `94` |  | `/// </summary>`
|  | `95` |  | `protected void PopulateClientExchangeValue()`
| 18 | `96` |  | `{`
| 18 | `97` |  | `if (_group.IsZero)`
| 0 | `98` |  | `{`
| 0 | `99` |  | `throw new ArgumentNullException("_group");`
|  | `100` |  | `}`
|  | `101` |  | ``
| 18 | `102` |  | `if (_prime.IsZero)`
| 0 | `103` |  | `{`
| 0 | `104` |  | `throw new ArgumentNullException("_prime");`
|  | `105` |  | `}`
|  | `106` |  | ``
|  | `107` |  | `// generate private exponent that is twice the hash size (RFC 4419) with a minimum`
|  | `108` |  | `// of 1024 bits (whatever is less)`
| 18 | `109` |  | `var privateExponentSize = Math.Max(HashSize * 2, 1024);`
|  | `110` |  | ``
|  | `111` |  | `BigInteger clientExchangeValue;`
|  | `112` |  | ``
|  | `113` |  | `do`
| 18 | `114` |  | `{`
|  | `115` |  | `// Create private component`
| 18 | `116` |  | `_privateExponent = BigInteger.Random(privateExponentSize);`
|  | `117` |  | ``
|  | `118` |  | `// Generate public component`
| 18 | `119` |  | `clientExchangeValue = BigInteger.ModPow(_group, _privateExponent, _prime);`
| 18 | `120` |  | `}`
| 18 | `121` |  | `while (clientExchangeValue < 1 || clientExchangeValue > (_prime - 1));`
|  | `122` |  | ``
| 18 | `123` |  | `_clientExchangeValue = clientExchangeValue.ToByteArray().Reverse();`
| 18 | `124` |  | `}`
|  | `125` |  | ``
|  | `126` |  | `/// <summary>`
|  | `127` |  | `/// Handles the server DH reply message.`
|  | `128` |  | `/// </summary>`
|  | `129` |  | `/// <param name="hostKey">The host key.</param>`
|  | `130` |  | `/// <param name="serverExchangeValue">The server exchange value.</param>`
|  | `131` |  | `/// <param name="signature">The signature.</param>`
|  | `132` |  | `protected virtual void HandleServerDhReply(byte[] hostKey, byte[] serverExchangeValue, byte[] signature)`
| 18 | `133` |  | `{`
| 18 | `134` |  | `_serverExchangeValue = serverExchangeValue;`
| 18 | `135` |  | `_hostKey = hostKey;`
| 18 | `136` |  | `SharedKey = BigInteger.ModPow(serverExchangeValue.ToBigInteger(), _privateExponent, _prime).ToByteArray().Re`
| 18 | `137` |  | `_signature = signature;`
| 18 | `138` |  | `}`
|  | `139` |  | `}`
|  | `140` |  | `}`

# Methods/Properties

ValidateExchangeHash()
Start(Renci.SshNet.Session,Renci.SshNet.Messages.Transport.KeyExchangeInitMessage)
PopulateClientExchangeValue()
HandleServerDhReply(System.Byte[],System.Byte[],System.Byte[])