implement Cipher; include "sys.m"; include "keyring.m";	kr: Keyring;	RC4state: import kr; include "sshio.m"; Cipherstate: adt{	enc: ref RC4state;	dec: ref RC4state;}; cs: ref Cipherstate; id(): int{	return SSH_CIPHER_RC4;} init(key: array of byte, isserver: int){	kr = load Keyring Keyring->PATH;	if(isserver)		cs = ref Cipherstate(kr->rc4setup(key[0:16]), kr->rc4setup(key[16:32]));	else		cs = ref Cipherstate(kr->rc4setup(key[16:32]), kr->rc4setup(key[0:16]));} encrypt(buf: array of byte, nbuf: int){	kr->rc4(cs.enc, buf, nbuf);} decrypt(buf: array of byte, nbuf: int){	kr->rc4(cs.dec, buf, nbuf);}