If you want to remove any particular algorithm supported by the client you can do so by editing the supported algorithms on the Ssh2Context.
For example to remove a Key Exchange or Public Key algorithm you can use the following code:
Ssh2Context ssh2Context = (Ssh2Context) con.getContext(SshConnector.SSH2);
// Key Exchange
ssh2Context.supportedKeyExchanges().remove(Ssh2Context.KEX_DIFFIE_HELLMAN_GROUP1_SHA1);
// Public Key
ssh2Context.supportedPublicKeys().remove(Ssh2Context.PUBLIC_KEY_SSHDSS);
When removing Ciphers or Hmacs you need to do this on both directions of the connection, client->server and server-client. For example:
Ssh2Context ssh2Context = (Ssh2Context) con.getContext(SshConnector.SSH2);
// Ciphers
ssh2Context.supportedCiphersCS().remove(Ssh2Context.CIPHER_ARCFOUR);
ssh2Context.supportedCiphersSC().remove(Ssh2Context.CIPHER_ARCFOUR);
// HMac
ssh2Context.supportedMacsCS().remove(Ssh2Context.HMAC_MD5);
ssh2Context.supportedMacsSC().remove(Ssh2Context.HMAC_MD5);
