B4X
SSH Tunnel Set Allowed Algorithms

Demonstrates how to explicitly set the algorithms allowed in the SSH connection protocol for SSH tunneling.
Note: This example requires Chilkat v9.5.0.99 or greater.
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Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

Dim ssh_tunnel As ChilkatSshTunnel
ssh_tunnel.Initialize("ssh_tunnel")

Dim json As ChilkatJsonObject
json.Initialize

'  Here are the algorithms supported by Chilkat at the time this example was written (14-June-2024)

'  ---------------------------
'  SSH Key-Exchange Algorithms
'  ---------------------------
'  curve25519-sha256
'  curve25519-sha256@libssh.org
'  ecdh-sha2-nistp256
'  ecdh-sha2-nistp384
'  ecdh-sha2-nistp521
'  diffie-hellman-group14-sha256
'  diffie-hellman-group16-sha512
'  diffie-hellman-group18-sha512
'  diffie-hellman-group-exchange-sha256
'  diffie-hellman-group1-sha1
'  diffie-hellman-group14-sha1
'  diffie-hellman-group-exchange-sha1

'  ---------------------------
'  SSH Host Key Algorithms
'  ---------------------------
'  ssh-ed25519
'  ecdsa-sha2-nistp256
'  ecdsa-sha2-nistp384
'  ecdsa-sha2-nistp521
'  rsa-sha2-256
'  rsa-sha2-512
'  ssh-rsa
'  ssh-dss

'  ---------------------------
'  SSH Cipher Algorithms
'  ---------------------------
'  chacha20-poly1305@openssh.com
'  aes128-ctr
'  aes256-ctr
'  aes192-ctr
'  aes128-cbc
'  aes256-cbc
'  aes192-cbc
'  aes128-gcm@openssh.com
'  aes256-gcm@openssh.com
'  twofish256-cbc
'  twofish128-cbc
'  blowfish-cbc

'  ---------------------------
'  SSH MAC Algorithms
'  ---------------------------
'  hmac-sha2-256
'  hmac-sha2-512
'  hmac-sha2-256-etm@openssh.com
'  hmac-sha2-512-etm@openssh.com
'  hmac-sha1-etm@openssh.com
'  hmac-sha1
'  hmac-ripemd160
'  hmac-sha1-96
'  hmac-md5

'  Specify the allowed key-exchange, host-key, cipher (i.e. encryption), and mac (i.e. hash) algorithms allowed, in the order of preference.
'  -------------------------------------------------------------------------------------------------------------------------------------------
'  Note: You typically should NOT explicitly set allowed algorithms.
'  By default, Chilkat orders algorithms according to best practices, and pays attention to vulnerabilities such as the "Terrapin Attack".
'  Hard-coding algorthims can make your application brittle and prone to breaking over a long period of time,
'  if a server (at some point in the future) changes its allowed algorithms, or if you connect to a different server,
'  such that the client (Chilkat) and server cannot find a set of mutually agreed-upon algorithms.
'  -------------------------------------------------------------------------------------------------------------------------------------------
Dim allowed_kex As String = "curve25519-sha256@libssh.org,ecdh-sha2-nistp256"
Dim allowed_hostKey As String = "ssh-ed25519,ecdsa-sha2-nistp256"
Dim allowed_cipher As String = "chacha20-poly1305@openssh.com,aes256-ctr"
Dim allowed_mac As String = "hmac-sha2-256,hmac-sha2-512"

json.UpdateString("kex", allowed_kex)
json.UpdateString("hostKey", allowed_hostKey)
json.UpdateString("cipher", allowed_cipher)
json.UpdateString("mac", allowed_mac)
ssh_tunnel.SetAllowedAlgorithms(json)

Dim port As Int = 22
success = ssh_tunnel.Connect("example.com", port)
If success <> True Then
    Log(ssh_tunnel.LastErrorText)
    Return
End If


Log("Connected.")

'  ....
'  ....