(Visual FoxPro) SSH Set Allowed Algorithms

See more SSH Examples

Demonstrates how to explicitly set the algorithms allowed in the SSH connection protocol.

Note: This example requires Chilkat v9.5.0.99 or greater.

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

LOCAL lnSuccess
LOCAL loSsh
LOCAL loJson
LOCAL lcAllowed_kex
LOCAL lcAllowed_hostKey
LOCAL lcAllowed_cipher
LOCAL lcAllowed_mac
LOCAL lnPort

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Ssh')
loSsh = CreateObject('Chilkat.Ssh')

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')

* 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.
* -------------------------------------------------------------------------------------------------------------------------------------------
lcAllowed_kex = "curve25519-sha256@libssh.org,ecdh-sha2-nistp256"
lcAllowed_hostKey = "ssh-ed25519,ecdsa-sha2-nistp256"
lcAllowed_cipher = "chacha20-poly1305@openssh.com,aes256-ctr"
lcAllowed_mac = "hmac-sha2-256,hmac-sha2-512"

loJson.UpdateString("kex",lcAllowed_kex)
loJson.UpdateString("hostKey",lcAllowed_hostKey)
loJson.UpdateString("cipher",lcAllowed_cipher)
loJson.UpdateString("mac",lcAllowed_mac)
loSsh.SetAllowedAlgorithms(loJson)

lnPort = 22
lnSuccess = loSsh.Connect("example.com",lnPort)
IF (lnSuccess <> 1) THEN
    ? loSsh.LastErrorText
    RELEASE loSsh
    RELEASE loJson
    CANCEL
ENDIF

? "Connected."

* ....
* ....

RELEASE loSsh
RELEASE loJson