Xbase++

SFTP Set Allowed Algorithms

See more SFTP Examples

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

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

Xbase++

LOCAL nSuccess
LOCAL oSftp
LOCAL oJson
LOCAL cAllowed_kex
LOCAL cAllowed_hostKey
LOCAL cAllowed_cipher
LOCAL cAllowed_mac
LOCAL nPort

nSuccess := 0

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

oSftp := CreateObject("Chilkat.SFtp")

oJson := 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.
//  -------------------------------------------------------------------------------------------------------------------------------------------
cAllowed_kex := "curve25519-sha256@libssh.org,ecdh-sha2-nistp256"
cAllowed_hostKey := "ssh-ed25519,ecdsa-sha2-nistp256"
cAllowed_cipher := "chacha20-poly1305@openssh.com,aes256-ctr"
cAllowed_mac := "hmac-sha2-256,hmac-sha2-512"

oJson:UpdateString("kex", cAllowed_kex)
oJson:UpdateString("hostKey", cAllowed_hostKey)
oJson:UpdateString("cipher", cAllowed_cipher)
oJson:UpdateString("mac", cAllowed_mac)
oSftp:SetAllowedAlgorithms(oJson)

nPort := 22
nSuccess := oSftp:Connect("example.com", nPort)
IF (nSuccess != 1)
    ? oSftp:LastErrorText
    oSftp:destroy()
    oJson:destroy()
    RETURN
ENDIF

? "Connected."

//  ....
//  ....

oSftp:destroy()
oJson:destroy()