Function silc_private_message_payload_encode
SYNOPSIS
SilcBuffer silc_private_message_payload_encode(uint16 flags,
uint16 data_len,
unsigned char *data,
SilcCipher cipher);
DESCRIPTION
Encodes private message payload into a buffer and returns it. If
the cipher is provided the packet is also encrypted here. It is provided
if the private message private keys are used.