In progress
proc XOR args {
if {[llength $args] == 1} { set args [lindex $args 0] }
set work [lindex $args 0]
set args [lrange $args 1 end]
foreach item $args {
set work [expr $work ^ $item]
}
return $work
}
proc leftshift {current polynominals} {
set selected [list]
foreach selector $polynominals {
lappend selected [string index $current $selector]
}
set new_bit [XOR $selected]
return "[string range $current 1 end][set new_bit]"
}
proc shrink_generate_keystream {seedA polynominalsA seedS polynominalsS keystream_length} {
set registerA $seedA
set registerS $seedS
set keystream {}
repeat {
repeat {
set new_bit [string index [set registerA [leftshift $registerA $polynominalsA]] end]
} until {[string index [set registerS [leftshift $registerS $polynominalsS]] end] == "1"}
} until {[string length $keystream] == $keystream_length}
}