The alleged crimes came to light following the cracking of the illegal EncroChat mobile phone platform by international law enforcement agencies in 2020.
Stephen Palmer, 40, of Swan Lane, was arrested on Friday 31 March 2023 after evidence was referred to detectives from the Kent and Essex Serious Crime Directorate.
He has since been charged with soliciting to murder an unknown person, and being in possession of and selling a handgun and a machine gun.
Mr Palmer is also alleged to have been concerned in the supply of cocaine and ketamine.
He was remanded in custody by Medway magistrates on Saturday 1 April and will next appear at Maidstone Crown Court on Monday 1 May.
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