sigma0.rb

# coding: utf-8
require_relative "sha256lib.rb"

# -----
# σ0(x)
# -----
# σ0(x) = ROTR(7, x) ^ ROTR(18, x) ^ SHR(3, x)

# -----
# Input
# -----
# default
x = 0b00000000000000000011111111111111 # 0b11101001101101011101101110100101
# argument passed
x = ARGV[0].to_i(2) if ARGV[0] # binary
# check arguments
if ARGV[0] && ARGV[0].size > 32
	puts "We only operate on 32-bit words in SHA-256. Your x is #{ARGV[0].size} bits."; exit
end

# ---------
# Animation
# ---------
system "clear"
puts "x:       #{bits(x)}"
puts "         #{'-'*32}"
puts "ROTR 7:  #{bits(x)}"
puts "ROTR 18: #{bits(x)}"
puts " SHR 3:  #{bits(x)}"
puts "         #{'-'*32}"
puts "σ0(x):"
sleep(0.1)

# ROTR(7, x)
(7+1).times do |i|
  system "clear"
  puts "x:       #{bits(x)}"
  puts "         #{'-'*32}"
  puts "ROTR 7:  #{bits(rotr(i, x))}"
  puts "ROTR 18: #{bits(x)}"
  puts " SHR 3:  #{bits(x)}"
  puts "         #{'-'*32}"
  puts "σ0(x):"
  sleep(0.1)
end
sleep(0.1)

# ROTR(18, x)
(18+1).times do |i|
  system "clear"
  puts "x:       #{bits(x)}"
  puts "         #{'-'*32}"
  puts "ROTR 7:  #{bits(rotr(7, x))}"
  puts "ROTR 18: #{bits(rotr(i, x))}"
  puts " SHR 3:  #{bits(x)}"
  puts "         #{'-'*32}"
  puts "σ0(x):"
  sleep(0.1)
end
sleep(0.1)

# SHR(3, x)
(3+1).times do |i|
  system "clear"
  puts "x:       #{bits(x)}"
  puts "         #{'-'*32}"
  puts "ROTR 7:  #{bits(rotr(7, x))}"
  puts "ROTR 18: #{bits(rotr(18, x))}"
  puts " SHR 3:  #{bits(shr(i, x))}"
  puts "         #{'-'*32}"
  puts "σ0(x):"
  sleep(0.1)
end
sleep(0.1)

# ROTR(7, x) ^ ROTR(18, x) ^ SHR(3, x)
32.downto(1) do |i|
  system "clear"
  puts "x:       #{bits(x)}"
  puts "         #{'-'*32}"
  puts "ROTR 7:  #{bits(rotr(7, x))}"
  puts "ROTR 18: #{bits(rotr(18, x))} XOR"
  puts " SHR 3:  #{bits(shr(3, x))} XOR"
  puts "         #{'-'*32}"
  puts "σ0(x):   #{bits(rotr(7, x) ^ rotr(18, x) ^ shr(3, x))[i-1..-1].rjust(32, " ")}"
  sleep(0.1)
end
sleep(1)