DataFlex

SSH Tunnel Set Allowed Algorithms

See more SSH Tunnel Examples

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.

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSsh_tunnel
    Variant vJson
    Handle hoJson
    String sAllowed_kex
    String sAllowed_hostKey
    String sAllowed_cipher
    String sAllowed_mac
    Integer iPort
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatSshTunnel)) To hoSsh_tunnel
    If (Not(IsComObjectCreated(hoSsh_tunnel))) Begin
        Send CreateComObject of hoSsh_tunnel
    End

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End

    // 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.
    // -------------------------------------------------------------------------------------------------------------------------------------------
    Move "curve25519-sha256@libssh.org,ecdh-sha2-nistp256" To sAllowed_kex
    Move "ssh-ed25519,ecdsa-sha2-nistp256" To sAllowed_hostKey
    Move "chacha20-poly1305@openssh.com,aes256-ctr" To sAllowed_cipher
    Move "hmac-sha2-256,hmac-sha2-512" To sAllowed_mac

    Get ComUpdateString Of hoJson "kex" sAllowed_kex To iSuccess
    Get ComUpdateString Of hoJson "hostKey" sAllowed_hostKey To iSuccess
    Get ComUpdateString Of hoJson "cipher" sAllowed_cipher To iSuccess
    Get ComUpdateString Of hoJson "mac" sAllowed_mac To iSuccess
    Get pvComObject of hoJson to vJson
    Get ComSetAllowedAlgorithms Of hoSsh_tunnel vJson To iSuccess

    Move 22 To iPort
    Get ComConnect Of hoSsh_tunnel "example.com" iPort To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoSsh_tunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Connected."

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


End_Procedure