public byte[] calculateH(byte[] clientversion, byte[] serverversion, byte[] clientKexPayload,
byte[] serverKexPayload, byte[] hostKey, DHGexParameters para)
{
HashForSSH2Types hash = new HashForSSH2Types("SHA1");
hash.updateByteString(clientversion);
hash.updateByteString(serverversion);
hash.updateByteString(clientKexPayload);
hash.updateByteString(serverKexPayload);
hash.updateByteString(hostKey);
if (para.getMin_group_len() > 0)