// RC4 crypt  by K-K 2003
#module "RC4"

//rc4_init password [,length_of_password]
#deffunc rc4_init str,int
	mref key,32
	mref kl,1
	if kl==0 :strlen kl,key
	// RC4 init
	rc4_x=0
	rc4_y=0
	dim rc4_dat,256
	repeat 256
		rc4_dat.cnt=cnt
	loop
	b=0
	repeat 256
		a=rc4_dat.cnt
		peek c,key,cnt\kl
		b=b+a+c & 0xff
		rc4_dat.cnt=rc4_dat.b
		rc4_dat.b=a
	loop
return

// rc4_crypt data, size [,offset]
#deffunc rc4_crypt val,int,int
	mref data,24
	;mref data,48
	mref size,1
	mref offset,2
	// RC4 crypt
	repeat size
		rc4_x=rc4_x+1 & 0xff
		a=rc4_dat.rc4_x
		rc4_y=rc4_y+a & 0xff
		b=rc4_dat.rc4_y
		rc4_dat.rc4_x=rc4_dat.rc4_y
		rc4_dat.rc4_y=a
		;
		peek c,data,cnt+offset
		a=a+b & 0xff
		c=c^rc4_dat.a
		poke data,cnt+offset,c
	loop
return

#global

	// sample
	s="message"
	strlen l,s
	mes "data:"+s

	rc4_init "password"
	rc4_crypt s,l
	mes "rc4crypt:"+s

	rc4_init "password"
	rc4_crypt s,l
	mes "data:"+s
stop