schneider
parent
60c28edffd
commit
51e7d5bbd1
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@ -0,0 +1,671 @@
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/*
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This program implements the ECIES public key encryption scheme based on the
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NIST B163 elliptic curve and the XTEA block cipher. The code was written
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as an accompaniment for an article published in phrack #63 and is released to
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the public domain.
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Original author: Phrack Staff
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Ported to ARM7TDMI: Jiri Pittner <jiri@pittnerovi.com>
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compiled by arm-elf-gcc (GCC) 4.0.1 and tested on LPC2106
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdint.h>
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static int xrandm=100000000;
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static int xrandm1=10000;
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static int xrandb1=51723621;
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int xmult(int p,int q)
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{
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int p1,p0,q1,q0;
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p1=p/xrandm1; p0=p%xrandm1;
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q1=q/xrandm1; q0=q%xrandm1;
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return (((p0*q1+p1*q0)%xrandm1)*xrandm1+p0*q0)%xrandm;
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}
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unsigned char rnd1()
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{
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static int a=123456789;
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a = (xmult(a,xrandb1)+1)%xrandm;
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return a & 0xff;
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}
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#define MACRO(A) do { A; } while(0)
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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#define NO_HTONL
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#ifndef NO_HTONL
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#define INT2CHARS(ptr, val) MACRO( *(uint32_t*)(ptr) = htonl(val) )
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#define CHARS2INT(ptr) ntohl(*(uint32_t*)(ptr))
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#else
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#if 1
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//compiles to a quite reasonable assembly code
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void INT2CHARS (unsigned char *ptr, uint32_t val)
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{
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*ptr++ =val; val>>=8;
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*ptr++ =val; val>>=8;
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*ptr++ =val; val>>=8;
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*ptr++ =val;
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}
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uint32_t CHARS2INT(const unsigned char *ptr)
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{
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uint32_t r;
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ptr+=3;
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r=*ptr--; r<<=8;
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r|=*ptr--; r<<=8;
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r|=*ptr--; r<<=8;
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r|=*ptr--;
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return r;
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}
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#else
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/* ARM architecture has a problem with non-word-aligned addresses
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the load/store of a 32-bit register behaves very counterintuitively in such a case
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void INT2CHARS (char *ptr, const uint32_t val)
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{
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uint32_t *p = (uint32_t *)ptr;
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*p=val;
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}
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uint32_t CHARS2INT(const char *ptr)
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{
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uint32_t *p = (uint32_t *)ptr;
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return *p;
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}
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*/
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/* this has the same problem */
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#define INT2CHARS(ptr, val) MACRO( *(uint32_t*)(ptr) = (uint32_t)val )
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#define CHARS2INT(ptr) (*(uint32_t*)(ptr))
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#endif
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#endif
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/******************************************************************************/
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#define DEGREE 163 /* the degree of the field polynomial */
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#define MARGIN 3 /* don't touch this */
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#define NUMWORDS ((DEGREE + MARGIN + 31) / 32)
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/* the following type will represent bit vectors of length (DEGREE+MARGIN) */
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typedef uint32_t bitstr_t[NUMWORDS];
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/* some basic bit-manipulation routines that act on these vectors follow */
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#define bitstr_getbit(A, idx) ((A[(idx) / 32] >> ((idx) % 32)) & 1)
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#define bitstr_setbit(A, idx) MACRO( A[(idx) / 32] |= 1 << ((idx) % 32) )
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#define bitstr_clrbit(A, idx) MACRO( A[(idx) / 32] &= ~(1 << ((idx) % 32)) )
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#define bitstr_clear(A) MACRO( memset(A, 0, sizeof(bitstr_t)) )
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#define bitstr_copy(A, B) MACRO( memcpy(A, B, sizeof(bitstr_t)) )
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#define bitstr_swap(A, B) MACRO( bitstr_t h; \
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bitstr_copy(h, A); bitstr_copy(A, B); bitstr_copy(B, h) )
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#define bitstr_is_equal(A, B) (! memcmp(A, B, sizeof(bitstr_t)))
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int bitstr_is_clear(const bitstr_t x)
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{
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int i;
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for(i = 0; i < NUMWORDS && ! *x++; i++);
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return i == NUMWORDS;
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}
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/* return the number of the highest one-bit + 1 */
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int bitstr_sizeinbits(const bitstr_t x)
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{
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int i;
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uint32_t mask;
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for(x += NUMWORDS, i = 32 * NUMWORDS; i > 0 && ! *--x; i -= 32);
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if (i)
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for(mask = ((uint32_t) 1) << 31; ! (*x & mask); mask >>= 1, i--);
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return i;
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}
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/* left-shift by 'count' digits */
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void bitstr_lshift(bitstr_t A, const bitstr_t B, int count)
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{
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int i, offs = 4 * (count / 32);
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memmove((void*)A + offs, B, sizeof(bitstr_t) - offs);
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memset(A, 0, offs);
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if (count %= 32) {
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for(i = NUMWORDS - 1; i > 0; i--)
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A[i] = (A[i] << count) | (A[i - 1] >> (32 - count));
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A[0] <<= count;
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}
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}
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/* (raw) import from a byte array */
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void bitstr_import(bitstr_t x, const char *s)
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{
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int i;
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for(x += NUMWORDS, i = 0; i < NUMWORDS; i++, s += 4)
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*--x = CHARS2INT(s);
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}
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/* (raw) export to a byte array */
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void bitstr_export(char *s, const bitstr_t x)
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{
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int i;
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for(x += NUMWORDS, i = 0; i < NUMWORDS; i++, s += 4)
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INT2CHARS(s, *--x);
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}
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/* export as hex string (null-terminated!) */
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void bitstr_to_hex(char *s, const bitstr_t x)
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{
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int i;
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for(x += NUMWORDS, i = 0; i < NUMWORDS; i++, s += 8)
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siprintf(s, "%08lx", *--x);
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}
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uint8_t letter2bin (const char c)
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{
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return c>'9' ? c+10-(c>='a'?'a':'A') : c-'0';
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}
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uint8_t octet2bin(const char* octet)
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{
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return (letter2bin(octet[0])<<4) | letter2bin(octet[1]);
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}
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void bin2letter(char *c, uint8_t b)
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{
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*c = b<10? '0'+b : 'A'+b-10;
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}
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void bin2octet(char *octet, uint8_t bin)
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{
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bin2letter(octet,bin>>4);
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bin2letter(octet+1,bin&0x0f);
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}
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uint32_t getword32(const char *s)
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{
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//little endian
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union {uint32_t i; uint8_t c[sizeof(uint32_t)];} r;
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r.c[3]=octet2bin(s);
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r.c[2]=octet2bin(s+2);
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r.c[1]=octet2bin(s+4);
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r.c[0]=octet2bin(s+6);
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return r.i;
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}
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/* import from a hex string */
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int bitstr_parse(bitstr_t x, const char *s)
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{
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int len;
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if ((s[len = strspn(s, "0123456789abcdefABCDEF")]) ||
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(len > NUMWORDS * 8))
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return -1;
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bitstr_clear(x);
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x += len / 8;
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if (len % 8) {
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*x=getword32(s);
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*x >>= 32 - 4 * (len % 8);
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s += len % 8;
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len &= ~7;
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}
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for(; *s; s += 8)
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*--x = getword32(s);
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return len;
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}
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/******************************************************************************/
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typedef bitstr_t elem_t; /* this type will represent field elements */
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elem_t poly; /* the reduction polynomial */
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#define field_set1(A) MACRO( A[0] = 1; memset(A + 1, 0, sizeof(elem_t) - 4) )
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int field_is1(const elem_t x)
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{
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int i;
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if (*x++ != 1) return 0;
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for(i = 1; i < NUMWORDS && ! *x++; i++);
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return i == NUMWORDS;
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}
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void field_add(elem_t z, const elem_t x, const elem_t y) /* field addition */
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{
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int i;
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for(i = 0; i < NUMWORDS; i++)
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*z++ = *x++ ^ *y++;
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}
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#define field_add1(A) MACRO( A[0] ^= 1 )
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/* field multiplication */
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void field_mult(elem_t z, const elem_t x, const elem_t y)
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{
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elem_t b;
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int i, j;
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/* assert(z != y); */
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bitstr_copy(b, x);
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if (bitstr_getbit(y, 0))
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bitstr_copy(z, x);
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else
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bitstr_clear(z);
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for(i = 1; i < DEGREE; i++) {
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for(j = NUMWORDS - 1; j > 0; j--)
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b[j] = (b[j] << 1) | (b[j - 1] >> 31);
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b[0] <<= 1;
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if (bitstr_getbit(b, DEGREE))
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field_add(b, b, poly);
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if (bitstr_getbit(y, i))
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field_add(z, z, b);
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}
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}
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void field_invert(elem_t z, const elem_t x) /* field inversion */
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{
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elem_t u, v, g, h;
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int i;
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bitstr_copy(u, x);
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bitstr_copy(v, poly);
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bitstr_clear(g);
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field_set1(z);
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while (! field_is1(u)) {
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i = bitstr_sizeinbits(u) - bitstr_sizeinbits(v);
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if (i < 0) {
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bitstr_swap(u, v); bitstr_swap(g, z); i = -i;
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}
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bitstr_lshift(h, v, i);
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field_add(u, u, h);
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bitstr_lshift(h, g, i);
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field_add(z, z, h);
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}
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}
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/******************************************************************************/
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/* The following routines do the ECC arithmetic. Elliptic curve points
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are represented by pairs (x,y) of elem_t. It is assumed that curve
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coefficient 'a' is equal to 1 (this is the case for all NIST binary
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curves). Coefficient 'b' is given in 'coeff_b'. '(base_x, base_y)'
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is a point that generates a large prime order group. */
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elem_t coeff_b, base_x, base_y;
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#define point_is_zero(x, y) (bitstr_is_clear(x) && bitstr_is_clear(y))
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#define point_set_zero(x, y) MACRO( bitstr_clear(x); bitstr_clear(y) )
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#define point_copy(x1, y1, x2, y2) MACRO( bitstr_copy(x1, x2); \
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bitstr_copy(y1, y2) )
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/* check if y^2 + x*y = x^3 + *x^2 + coeff_b holds */
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int is_point_on_curve(const elem_t x, const elem_t y)
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{
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elem_t a, b;
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if (point_is_zero(x, y))
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return 1;
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field_mult(a, x, x);
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field_mult(b, a, x);
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field_add(a, a, b);
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field_add(a, a, coeff_b);
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field_mult(b, y, y);
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field_add(a, a, b);
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field_mult(b, x, y);
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return bitstr_is_equal(a, b);
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}
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void point_double(elem_t x, elem_t y) /* double the point (x,y) */
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{
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if (! bitstr_is_clear(x)) {
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elem_t a;
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field_invert(a, x);
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field_mult(a, a, y);
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field_add(a, a, x);
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field_mult(y, x, x);
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field_mult(x, a, a);
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field_add1(a);
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field_add(x, x, a);
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field_mult(a, a, x);
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field_add(y, y, a);
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}
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else
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bitstr_clear(y);
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}
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/* add two points together (x1, y1) := (x1, y1) + (x2, y2) */
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void point_add(elem_t x1, elem_t y1, const elem_t x2, const elem_t y2)
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{
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if (! point_is_zero(x2, y2)) {
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if (point_is_zero(x1, y1))
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point_copy(x1, y1, x2, y2);
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else {
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if (bitstr_is_equal(x1, x2)) {
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if (bitstr_is_equal(y1, y2))
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point_double(x1, y1);
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else
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point_set_zero(x1, y1);
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}
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else {
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elem_t a, b, c, d;
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field_add(a, y1, y2);
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field_add(b, x1, x2);
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field_invert(c, b);
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field_mult(c, c, a);
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field_mult(d, c, c);
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field_add(d, d, c);
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field_add(d, d, b);
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field_add1(d);
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field_add(x1, x1, d);
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field_mult(a, x1, c);
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field_add(a, a, d);
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field_add(y1, y1, a);
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bitstr_copy(x1, d);
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}
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}
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}
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}
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/******************************************************************************/
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typedef bitstr_t exp_t;
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exp_t base_order;
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/* point multiplication via double-and-add algorithm */
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void point_mult(elem_t x, elem_t y, const exp_t exp)
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{
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elem_t X, Y;
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int i;
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point_set_zero(X, Y);
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for(i = bitstr_sizeinbits(exp) - 1; i >= 0; i--) {
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point_double(X, Y);
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if (bitstr_getbit(exp, i))
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point_add(X, Y, x, y);
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}
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point_copy(x, y, X, Y);
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}
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/* draw a random value 'exp' with 1 <= exp < n */
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//@@@ Make a HARDWARE randomness generator with ARM, at the moment just a simple pseudorandom replacement
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void get_random_exponent(exp_t exp)
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{
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unsigned char buf[4 * NUMWORDS];
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int r ;
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do {
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for(r=0; r<4 * NUMWORDS; ++r)
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{
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buf[r]= rnd1();
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}
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bitstr_import(exp, buf);
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for(r = bitstr_sizeinbits(base_order) - 1; r < NUMWORDS * 32; r++)
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bitstr_clrbit(exp, r);
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} while(bitstr_is_clear(exp));
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}
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/******************************************************************************/
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void XTEA_init_key(uint32_t *k, const char *key)
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{
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k[0] = CHARS2INT(key + 0); k[1] = CHARS2INT(key + 4);
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k[2] = CHARS2INT(key + 8); k[3] = CHARS2INT(key + 12);
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}
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/* the XTEA block cipher */
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void XTEA_encipher_block(char *data, const uint32_t *k)
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{
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uint32_t sum = 0, delta = 0x9e3779b9, y, z;
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int i;
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y = CHARS2INT(data); z = CHARS2INT(data + 4);
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for(i = 0; i < 32; i++) {
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y += ((z << 4 ^ z >> 5) + z) ^ (sum + k[sum & 3]);
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sum += delta;
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z += ((y << 4 ^ y >> 5) + y) ^ (sum + k[(sum >> 11) & 3]);
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}
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INT2CHARS(data, y); INT2CHARS(data + 4, z);
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}
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/* encrypt in CTR mode */
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void XTEA_ctr_crypt(char *data, int size, const char *key)
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{
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uint32_t k[4], ctr = 0;
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int len, i;
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char buf[8];
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XTEA_init_key(k, key);
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while(size) {
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INT2CHARS(buf, 0); INT2CHARS(buf + 4, ctr++);
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XTEA_encipher_block(buf, k);
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len = MIN(8, size);
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for(i = 0; i < len; i++)
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*data++ ^= buf[i];
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size -= len;
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}
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}
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/* calculate the CBC MAC */
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void XTEA_cbcmac(char *mac, const char *data, int size, const char *key)
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{
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uint32_t k[4];
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int len, i;
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XTEA_init_key(k, key);
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INT2CHARS(mac, 0L);
|
||||
INT2CHARS(mac + 4, size);
|
||||
XTEA_encipher_block(mac, k);
|
||||
while(size) {
|
||||
len = MIN(8, size);
|
||||
for(i = 0; i < len; i++)
|
||||
mac[i] ^= *data++;
|
||||
XTEA_encipher_block(mac, k);
|
||||
size -= len;
|
||||
}
|
||||
}
|
||||
|
||||
/* modified(!) Davies-Meyer construction.*/
|
||||
void XTEA_davies_meyer(char *out, const char *in, int ilen)
|
||||
{
|
||||
uint32_t k[4];
|
||||
char buf[8];
|
||||
int i;
|
||||
memset(out, 0, 8);
|
||||
while(ilen--) {
|
||||
XTEA_init_key(k, in);
|
||||
memcpy(buf, out, 8);
|
||||
XTEA_encipher_block(buf, k);
|
||||
for(i = 0; i < 8; i++)
|
||||
out[i] ^= buf[i];
|
||||
in += 16;
|
||||
}
|
||||
}
|
||||
|
||||
/******************************************************************************/
|
||||
|
||||
void ECIES_generate_key_pair(void) /* generate a public/private key pair */
|
||||
{
|
||||
char buf[8 * NUMWORDS + 1], *bufptr = buf + NUMWORDS * 8 - (DEGREE + 3) / 4;
|
||||
elem_t x, y;
|
||||
exp_t k;
|
||||
get_random_exponent(k);
|
||||
point_copy(x, y, base_x, base_y);
|
||||
point_mult(x, y, k);
|
||||
/*
|
||||
uart0Puts("Here is your new public/private key pair:\n");
|
||||
bitstr_to_hex(buf, x); uart0Puts("Public key: "); uart0Puts(bufptr); uart0Putch(':');
|
||||
bitstr_to_hex(buf, y); uart0Puts(bufptr);
|
||||
bitstr_to_hex(buf, k); uart0Puts("\nPrivate key: "); uart0Puts(bufptr); uart0Putch('\n');
|
||||
*/
|
||||
}
|
||||
|
||||
/* check that a given elem_t-pair is a valid point on the curve != 'o' */
|
||||
int ECIES_embedded_public_key_validation(const elem_t Px, const elem_t Py)
|
||||
{
|
||||
return (bitstr_sizeinbits(Px) > DEGREE) || (bitstr_sizeinbits(Py) > DEGREE) ||
|
||||
point_is_zero(Px, Py) || ! is_point_on_curve(Px, Py) ? -1 : 1;
|
||||
}
|
||||
|
||||
/* same thing, but check also that (Px,Py) generates a group of order n */
|
||||
int ECIES_public_key_validation(const char *Px, const char *Py)
|
||||
{
|
||||
elem_t x, y;
|
||||
if ((bitstr_parse(x, Px) < 0) || (bitstr_parse(y, Py) < 0))
|
||||
return -1;
|
||||
if (ECIES_embedded_public_key_validation(x, y) < 0)
|
||||
return -1;
|
||||
point_mult(x, y, base_order);
|
||||
return point_is_zero(x, y) ? 1 : -1;
|
||||
}
|
||||
|
||||
void ECIES_kdf(char *k1, char *k2, const elem_t Zx, /* a non-standard KDF */
|
||||
const elem_t Rx, const elem_t Ry)
|
||||
{
|
||||
int bufsize = (3 * (4 * NUMWORDS) + 1 + 15) & ~15;
|
||||
char buf[bufsize];
|
||||
memset(buf, 0, bufsize);
|
||||
bitstr_export(buf, Zx);
|
||||
bitstr_export(buf + 4 * NUMWORDS, Rx);
|
||||
bitstr_export(buf + 8 * NUMWORDS, Ry);
|
||||
buf[12 * NUMWORDS] = 0; XTEA_davies_meyer(k1, buf, bufsize / 16);
|
||||
buf[12 * NUMWORDS] = 1; XTEA_davies_meyer(k1 + 8, buf, bufsize / 16);
|
||||
buf[12 * NUMWORDS] = 2; XTEA_davies_meyer(k2, buf, bufsize / 16);
|
||||
buf[12 * NUMWORDS] = 3; XTEA_davies_meyer(k2 + 8, buf, bufsize / 16);
|
||||
}
|
||||
|
||||
#define ECIES_OVERHEAD (8 * NUMWORDS + 8)
|
||||
|
||||
/* ECIES encryption; the resulting cipher text message will be
|
||||
(len + ECIES_OVERHEAD) bytes long */
|
||||
void ECIES_encryption(char *msg, const char *text, int len,
|
||||
const char *Px, const char *Py)
|
||||
{
|
||||
elem_t Rx, Ry, Zx, Zy;
|
||||
char k1[16], k2[16];
|
||||
exp_t k;
|
||||
//memset(msg,0,len+ECIES_OVERHEAD); //in the case buffer was not clean
|
||||
do {
|
||||
get_random_exponent(k);
|
||||
bitstr_parse(Zx, Px);
|
||||
bitstr_parse(Zy, Py);
|
||||
point_mult(Zx, Zy, k);
|
||||
point_double(Zx, Zy); /* cofactor h = 2 on B163 */
|
||||
} while(point_is_zero(Zx, Zy));
|
||||
point_copy(Rx, Ry, base_x, base_y);
|
||||
point_mult(Rx, Ry, k);
|
||||
ECIES_kdf(k1, k2, Zx, Rx, Ry);
|
||||
bitstr_export(msg, Rx);
|
||||
bitstr_export(msg + 4 * NUMWORDS, Ry);
|
||||
memcpy(msg + 8 * NUMWORDS, text, len);
|
||||
XTEA_ctr_crypt(msg + 8 * NUMWORDS, len, k1);
|
||||
XTEA_cbcmac(msg + 8 * NUMWORDS + len, msg + 8 * NUMWORDS, len, k2);
|
||||
}
|
||||
|
||||
/* ECIES decryption */
|
||||
int ECIES_decryption(char *text, const char *msg, int len,
|
||||
const char *privkey)
|
||||
{
|
||||
elem_t Rx, Ry, Zx, Zy;
|
||||
char k1[16], k2[16], mac[8];
|
||||
exp_t d;
|
||||
bitstr_import(Rx, msg);
|
||||
bitstr_import(Ry, msg + 4 * NUMWORDS);
|
||||
if (ECIES_embedded_public_key_validation(Rx, Ry) < 0)
|
||||
return -1;
|
||||
bitstr_parse(d, privkey);
|
||||
point_copy(Zx, Zy, Rx, Ry);
|
||||
point_mult(Zx, Zy, d);
|
||||
point_double(Zx, Zy); /* cofactor h = 2 on B163 */
|
||||
if (point_is_zero(Zx, Zy))
|
||||
return -1;
|
||||
ECIES_kdf(k1, k2, Zx, Rx, Ry);
|
||||
|
||||
XTEA_cbcmac(mac, msg + 8 * NUMWORDS, len, k2);
|
||||
if (memcmp(mac, msg + 8 * NUMWORDS + len, 8))
|
||||
return -1;
|
||||
memcpy(text, msg + 8 * NUMWORDS, len);
|
||||
XTEA_ctr_crypt(text, len, k1);
|
||||
return 1;
|
||||
}
|
||||
|
||||
/******************************************************************************/
|
||||
/******************************************************************************/
|
||||
|
||||
#include "basic/basic.h"
|
||||
|
||||
#include "lcd/render.h"
|
||||
#include "lcd/allfonts.h"
|
||||
|
||||
|
||||
void encryption_decryption_demo(const char *text, const char *public_x,
|
||||
const char *public_y, const char *private)
|
||||
{
|
||||
int len = strlen(text) + 1;
|
||||
|
||||
//this used to be a malloc: made the buffer static for a maximum message
|
||||
//size of 100
|
||||
|
||||
char *encrypted[100 + ECIES_OVERHEAD];
|
||||
char *decrypted[100];
|
||||
|
||||
//uart0Puts("plain text: "); uart0Puts(text); uart0Putch('\n');
|
||||
ECIES_encryption(encrypted, text, len, public_x, public_y); /* encryption */
|
||||
/*uart0Puts("encrypted: ");
|
||||
{int i;
|
||||
for(i=0; i<len + ECIES_OVERHEAD; ++i)
|
||||
{
|
||||
char tmp[9];
|
||||
siprintf(tmp,"%02x ",(unsigned char)encrypted[i]);
|
||||
uart0Puts(tmp);
|
||||
}
|
||||
}
|
||||
uart0Putch('\n');
|
||||
*/
|
||||
|
||||
if (ECIES_decryption(decrypted, encrypted, len, private) < 0) /* decryption */
|
||||
{//uart0Puts("decryption failed! :"); uart0Puts(decrypted); uart0Putch('\n');
|
||||
DoString(0,0,"dec fail");
|
||||
}
|
||||
else
|
||||
{
|
||||
//uart0Puts("after encryption/decryption: "); uart0Puts(decrypted); uart0Putch('\n');
|
||||
DoString(0,0,decrypted);
|
||||
}
|
||||
}
|
||||
|
||||
int8_t endianity(void)
|
||||
{
|
||||
int8_t jj= -1;
|
||||
union {uint32_t i; char z[sizeof(uint32_t)];} u;
|
||||
u.i=1;
|
||||
jj=0; while(!u.z[jj]) jj++;
|
||||
return jj;
|
||||
}
|
||||
|
||||
|
||||
void module_schneider(void)
|
||||
{ /* the coefficients for B163 */
|
||||
bitstr_parse(poly, "800000000000000000000000000000000000000c9");
|
||||
bitstr_parse(coeff_b, "20a601907b8c953ca1481eb10512f78744a3205fd");
|
||||
bitstr_parse(base_x, "3f0eba16286a2d57ea0991168d4994637e8343e36");
|
||||
bitstr_parse(base_y, "0d51fbc6c71a0094fa2cdd545b11c5c0c797324f1");
|
||||
bitstr_parse(base_order, "40000000000000000000292fe77e70c12a4234c33");
|
||||
|
||||
DoString(0,8,"test");
|
||||
|
||||
ECIES_generate_key_pair(); /* generate a public/private key pair */
|
||||
|
||||
encryption_decryption_demo("This secret demo message will be ECIES encrypted",
|
||||
"1c56d302cf642a8e1ba4b48cc4fbe2845ee32dce7",
|
||||
"45f46eb303edf2e62f74bd68368d979e265ee3c03",
|
||||
"0e10e787036941e6c78daf8a0e8e1dbfac68e26d2");
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue