little helper for generating multiplication tables for multiplication in GF(2**8)

diff --git a/host/gf256_table_gen.c b/host/gf256_table_gen.c
new file mode 100644 (file)
index 0000000..87887d6
--- /dev/null
+++ b/host/gf256_table_gen.c
@@ -0,0 +1,153 @@
+/* gf256_table_gen.c */
+/*
+    This file is part of the Crypto-avr-lib/microcrypt-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/>.
+*/
+/**
+ * \file     gf256_table_gen.c
+ * \email    daniel.otte@rub.de
+ * \author   Daniel Otte 
+ * \date     2009-01-13
+ * \license  GPLv3 or later
+ * 
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include "gf256mul.h"
+
+int print_header =  1,
+    print_braces =  1,
+    print_base   =  1,
+    print_align  =  1,
+    print_prefix =  1;
+
+char* fmt_strings[]={"%d", "%3d",
+                     "%X", "%2.2X",
+                     "%o", "%3o",
+                     "%d", "%3d",
+                     "0x%X", "0x%2.2X",
+                     "0%o", "0%3o"};
+                     
+int main(int argc, char** argv){
+       int i,j;
+       int c;
+       int option_index=0;
+       char* fmt=NULL;
+       static struct option long_options[] =
+             {
+               /* These options set a flag. */
+               {"print-header",    no_argument, &print_header, 1},
+               {"no-print-header", no_argument, &print_header, 0},
+               {"print-braces",    no_argument, &print_braces, 1},
+               {"no-print-braces", no_argument, &print_braces, 0},
+               {"print-dec",       no_argument, &print_base, 0},
+               {"print-hex",       no_argument, &print_base, 1},
+               {"print-octal",     no_argument, &print_base, 2},
+               {"align",           no_argument, &print_align, 1},
+               {"no-align",        no_argument, &print_align, 0},
+               {"print-prefix",    no_argument, &print_prefix, 1},
+               {"no-print-prefix", no_argument, &print_prefix, 0},
+               
+               /* These options don't set a flag.
+                  We distinguish them by their indices. */
+               {"reducer", required_argument, 0, 'r'},
+               {"min",     required_argument, 0, 'l'},
+               {"max",     required_argument, 0, 'u'},
+               {"format",  required_argument, 0, 'f'},
+               {0, 0, 0, 0}
+             };
+
+       
+       
+       unsigned long ul_a;
+       int columns=8;
+       unsigned long ul_reducer=0x1b, max=0xff, min=0x00;
+       uint8_t reducer, a;
+       char** eptr;
+       FILE* of = stdout;
+       while(c!=-1){
+               c = getopt_long(argc, argv,"cCbBdhoaApPr:l:u:f:", 
+                               long_options, &option_index);
+               switch(c){
+                       case 'c': print_header=1; break;
+                       case 'C': print_header=0; break;
+                       case 'b': print_braces=1; break;
+                       case 'B': print_braces=0; break;
+                       case 'h': print_base = 1; break;
+                       case 'd': print_base = 0; break;
+                       case 'o': print_base = 2; break;
+                       case 'a': print_align =1; break;
+                       case 'A': print_align =0; break;
+                       case 'p': print_prefix=1; break;
+                       case 'P': print_prefix=0; break;
+                       case 'r': ul_reducer = strtoul(optarg, eptr, 0);
+                                 if((**eptr)!='\0'){
+                                            fprintf(stderr, "Error, invalid reducer value \"%s\"!\n",
+                                                    optarg);
+                                            return -1;
+                                         }
+                                         break;
+                       case 'l': min = strtoul(optarg, eptr, 0);
+                                 if(((**eptr)!='\0')||min>0xff){
+                                            fprintf(stderr, "Error, invalid minimum value \"%s\"!\n",
+                                                    optarg);
+                                            return -1;
+                                         }
+                                         break;
+                       case 'u': max = strtoul(optarg, eptr, 0);
+                                 if(((**eptr)!='\0')||max>0xff){
+                                            fprintf(stderr, "Error, invalid maximum value \"%s\"!\n",
+                                                    optarg);
+                                            return -1;
+                                         }
+                                         break;
+                       case 'f': fmt = optarg; break;
+                       default: break;
+               }
+       }
+       reducer = ul_reducer&0xff;
+       if(!fmt)
+               fmt = fmt_strings[print_prefix*6+print_base*2+print_align];
+       
+       for(i=optind; i<argc; ++i){
+               ul_a=strtoul(argv[i], eptr, 0)&0xff;
+               if(((**eptr)!='\0')|| ul_a>0xff){
+                       fprintf(stderr, "Error, invalid number \"%s\"!\n", argv[i]);
+                       return -1;
+               }
+               a = ul_a;
+               if(print_header)
+                       fprintf(of,"\nuint8_t lut_gfmul_%s_%2.2x",argv[i],reducer);
+               if(print_braces)
+                       fprintf(of," = {\n\t");
+               
+               for(j=min; j<=max-1; ++j){
+                       fprintf(of,fmt,gf256mul(a, j, reducer));
+                       if(j%columns==columns-1){
+                               fprintf(of, ",\n\t");
+                       }else{
+                               fprintf(of, ", ");
+                       }
+               }
+               fprintf(of, fmt, gf256mul(a,max, reducer));
+               if(print_braces)
+                       fprintf(of, " }");
+               fprintf(of, "\n\n");    
+       }
+       return 0;
+}

diff --git a/host/gf256mul.c b/host/gf256mul.c
new file mode 100644 (file)
index 0000000..3da67cb
--- /dev/null
+++ b/host/gf256mul.c
@@ -0,0 +1,42 @@
+/* gf256mul.c */
+/*
+    This file is part of the Crypto-avr-lib/microcrypt-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/>.
+*/
+/**
+ * \file     gf256mul.c
+ * \email    daniel.otte@rub.de
+ * \author   Daniel Otte 
+ * \date     2009-01-13
+ * \license  GPLv3 or later
+ * 
+ */
+#include <stdint.h>
+#include "gf256mul.h"
+
+uint8_t gf256mul(uint8_t a, uint8_t b, uint8_t reducer){
+       uint8_t t,ret=0;
+       while(a){
+               if(a&1)
+                       ret ^= b;
+               t=a&0x80;
+               b<<=1;
+               if(t)
+                       b^=reducer;
+               a>>=1;
+       }
+       return ret;
+}

diff --git a/host/gf256mul.h b/host/gf256mul.h
new file mode 100644 (file)
index 0000000..f1a61bb
--- /dev/null
+++ b/host/gf256mul.h
@@ -0,0 +1,29 @@
+/* gf256mul.h */
+/*
+    This file is part of the Crypto-avr-lib/microcrypt-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/>.
+*/
+/**
+ * \file     gf256mul.h
+ * \email    daniel.otte@rub.de
+ * \author   Daniel Otte 
+ * \date     2009-01-13
+ * \license  GPLv3 or later
+ * 
+ */
+#include <stdint.h>
+
+uint8_t gf256mul(uint8_t a, uint8_t b, uint8_t reducer);