--- /dev/null
+#!/usr/bin/ruby
+# shavs_test.rb
+=begin
+ This file is part of the AVR-Crypto-Lib.
+ Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+=end
+
+shift_values = [ 5, 36, 13, 58, 26, 53, 11, 59,
+ 56, 28, 46, 44, 20, 35, 42, 50,
+
+ 38, 48, 34, 26, 33, 39, 29, 33,
+ 30, 20, 14, 12, 49, 27, 26, 51,
+ 50, 43, 15, 58, 8, 41, 11, 39,
+ 53, 31, 27, 7, 42, 14, 9, 35,
+
+ 55, 25, 33, 34, 28, 17, 58, 47,
+ 43, 25, 8, 43, 7, 6, 7, 49,
+ 37, 46, 18, 25, 47, 18, 32, 27,
+ 40, 13, 57, 60, 48, 25, 45, 58,
+ 16, 14, 21, 44, 51, 43, 19, 37,
+ 22, 13, 12, 9, 9, 42, 18, 48,
+ 38, 52, 32, 59, 35, 40, 2, 53,
+ 12, 57, 54, 34, 41, 15, 56, 56 ]
+
+def transform_shift(value)
+ byteshift = (value+3)/8
+ singleshift = value%8
+ if singleshift>4
+ # byteshift += 1
+ singleshift -= 8
+ end
+ return [singleshift, byteshift]
+end
+
+def transform_singleshift(value)
+ if(value>=0)
+ return value
+ end
+ return 0x08+(value*-1)
+end
+
+bs_hist = Hash.new
+bs_hist.default = 0
+ss_hist = Hash.new
+ss_hist.default = 0
+shift_values.each{|v|
+
+ a = transform_shift(v)
+ printf("%2d = %2d * 8 %+2d\n", v, a[1], a[0])
+ bs_hist[a[1]] += 1
+ ss_hist[a[0]] += 1
+}
+
+puts("byteshift histogram:")
+for i in 0..7
+ printf("%d: %4d\n", i, bs_hist[i])
+ end
+
+puts("singleshift histogram:")
+for i in -3..4
+ printf("%+d: %4d\n", i, ss_hist[i])
+ end
+
+(0..shift_values.length-1).each{|i|
+ a = transform_shift(shift_values[i])
+ a[0] = transform_singleshift(a[0])
+ printf("0x%01x%01x, ", a[1], a[0])
+ puts("") if (i%8==7)
+}