int FMT_crypt_load(const char *fname, byte_string_t bs, const char *password)
{
FILE *infp;
byte_string_t K, W;
int result = 0;
infp = fopen(fname, "r");
if (!infp) return 0;
byte_string_set(K, password);
advance_to("W:", infp);
mime_get(W, infp);
if (1 != crypto_decrypt(bs, W, K)) {
fprintf(stderr, "crypto_decrypt() failed!\n");
} else {
result = 1;
}
fclose(infp);
byte_string_clear(K);
byte_string_clear(W);
return result;
}
void byte_string_set_point(byte_string_t bs, point_t P)
{
byte_string_t bs1, bs2;
byte_string_set_fp2(bs1, P->x);
byte_string_set_fp2(bs2, P->y);
byte_string_join(bs, bs1, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
}
void byte_string_set_fp2(byte_string_t bs, fp2_t x)
{
byte_string_t bs1, bs2;
byte_string_set_mpz(bs1, x->a);
byte_string_set_mpz(bs2, x->b);
byte_string_join(bs, bs1, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
}
void point_set_byte_string(point_t P, byte_string_t bs)
{
byte_string_t bs1, bs2;
byte_string_split(bs1, bs2, bs);
fp2_set_byte_string(P->x, bs1);
fp2_set_byte_string(P->y, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
}
void fp2_set_byte_string(fp2_t x, byte_string_t bs)
{
byte_string_t bs1, bs2;
byte_string_split(bs1, bs2, bs);
mympz_set_byte_string(x->a, bs1);
mympz_set_byte_string(x->b, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
}
int FMT_crypt_save_fp(FILE *outfp, byte_string_t bs, const char *password)
{
byte_string_t K, W;
byte_string_set(K, password);
crypto_encrypt(W, bs, K);
fprintf(outfp, "\nW:\n");
mime_put(W, outfp);
byte_string_clear(K);
byte_string_clear(W);
return 1;
}
int
main(void)
{
char *id = "argp at domain cs.tcd.ie";
params_t params;
byte_string_t U;
byte_string_t secret;
byte_string_t key;
byte_string_t master;
IBE_init();
IBE_setup(params, master, 512, 160, "test");
printf("system parameters generated!\n");
printf("IBE test program\n");
printf("Test ID: %s\n", id);
printf("generating key...\n");
IBE_KEM_encrypt(secret, U, id, params);
printf("U =");
byte_string_printf(U, " %02X");
printf("\n");
printf("secret =");
byte_string_printf(secret, " %02X");
printf("\n");
byte_string_clear(secret);
printf("extracting...\n");
IBE_extract(key, master, id, params);
printf("recovering secret...\n");
IBE_KEM_decrypt(secret, U, key, params);
/* hopefully it will be the same as above */
printf("secret =");
byte_string_printf(secret, " %02X");
printf("\n");
params_clear(params);
IBE_clear();
byte_string_clear(U);
byte_string_clear(key);
byte_string_clear(secret);
byte_string_clear(master);
return(0);
}
int IBE_serialize_params(byte_string_t bs, params_t params)
//put system parameters into a byte_string
{
int i, j;
byte_string_t *bsa;
i = 0;
bsa = (byte_string_t *) malloc(sizeof(byte_string_t)
* (2 * params->sharen + 20));
byte_string_set(bsa[i++], params->version);
byte_string_set(bsa[i++], params->id);
byte_string_set_mpz(bsa[i++], params->p);
byte_string_set_mpz(bsa[i++], params->q);
byte_string_set_point(bsa[i++], params->P);
byte_string_set_point(bsa[i++], params->Ppub);
byte_string_set_int(bsa[i++], params->sharet);
byte_string_set_int(bsa[i++], params->sharen);
for (j=0; j<params->sharen; j++) {
byte_string_set_mpz(bsa[i++], params->robustx[j]);
byte_string_set_point(bsa[i++], params->robustP[j]);
}
byte_string_encode_array(bs, bsa, i);
for (j=0; j<i; j++) {
byte_string_clear(bsa[j]);
}
return 1;
}
int FMT_split_master(char **fname, byte_string_t master, int t, int n, params_t params)
{
int i;
/* byte_string_t mshare[n]; */
byte_string_t *mshare;
int result = 1;
mshare = (byte_string_t *)malloc((sizeof(byte_string_t) * n));
IBE_split_master(mshare, master, t, n, params);
for (i=0; i<n; i++) {
if (1 != FMT_save_byte_string(fname[i], mshare[i])) {
fprintf(stderr, "error writing to %s\n", fname[i]);
result = 0;
break;
}
}
for (i=0; i<n; i++) {
byte_string_clear(mshare[i]);
}
free(mshare);
return result;
}
int FMT_load_raw_byte_string(byte_string_t bs, char *file)
//load a raw byte string from a file
{
int max = 1024;
int len = 0;
FILE *fp;
fp = fopen(file, "r");
if (!fp) {
return 0;
}
byte_string_init(bs, max);
for(;;) {
len += fread(&bs->data[len], 1, max - len, fp);
if (len == max) {
max *= 2;
byte_string_reinit(bs, max);
} else {
if (!feof(fp)) {
fclose(fp);
byte_string_clear(bs);
return 0;
}
fclose(fp);
break;
}
}
byte_string_reinit(bs, len);
return 1;
}
static void map_to_point(point_t d, const char *id, params_t params)
//converts id into a point of order q on E/F_p
{
byte_string_t bsid;
byte_string_set(bsid, id);
map_byte_string_to_point(d, bsid, params);
byte_string_clear(bsid);
}
void IBE_extract(byte_string_t bs,
byte_string_t master, const char *id, params_t params)
//same as above, char * version
{
byte_string_t bsid;
byte_string_set(bsid, id);
IBE_extract_byte_string(bs, master, bsid, params);
byte_string_clear(bsid);
}
void IBE_extract_share(byte_string_t share,
byte_string_t mshare, const char *id, params_t params)
//same as above except takes in char * instead of byte_string
{
byte_string_t bsid;
byte_string_set(bsid, id);
IBE_extract_share_byte_string(share, mshare, bsid, params);
byte_string_clear(bsid);
}
int IBE_deserialize_params(params_t params, byte_string_t bs)
//get system parameters from a byte_string
{
byte_string_t *bsa;
int n;
int i, j;
byte_string_decode_array(&bsa, &n, bs);
//TODO: check n is big enough
i = 0;
params->version = charstar_from_byte_string(bsa[i++]);
params->id = charstar_from_byte_string(bsa[i++]);
mpz_init(params->p);
mpz_init(params->q);
mympz_set_byte_string(params->p, bsa[i++]);
mympz_set_byte_string(params->q, bsa[i++]);
initpq(params);
point_init(params->P);
point_init(params->Ppub);
point_set_byte_string(params->P, bsa[i++]);
point_set_byte_string(params->Ppub, bsa[i++]);
point_init(params->PhiPpub);
point_Phi(params->PhiPpub, params->Ppub, params);
params->sharet = int_from_byte_string(bsa[i++]);
params->sharen = int_from_byte_string(bsa[i++]);
params->robustx = (mpz_t *) malloc(params->sharen * sizeof(mpz_t));
params->robustP = (point_t *) malloc(params->sharen * sizeof(point_t));
for (j=0; j<params->sharen; j++) {
mpz_init(params->robustx[j]);
mympz_set_byte_string(params->robustx[j], bsa[i++]);
//TODO: check it's different from others
point_init(params->robustP[j]);
point_set_byte_string(params->robustP[j], bsa[i++]);
}
point_mul_preprocess(params->P, params->curve);
miller_cache_init(params->Ppub_mc, params->curve);
tate_preprocess(params->Ppub_mc, params->Ppub, params->curve);
for(i=0; i<n; i++) {
byte_string_clear(bsa[i]);
}
free(bsa);
return 1;
}
void hash_H(byte_string_t md_value, fp2_t x, params_t params)
//hash a point of E/F_p^2 to a byte_string
{
byte_string_t bs;
byte_string_set_fp2(bs, x);
crypto_hash(md_value, bs);
byte_string_clear(bs);
}
void hash_G(mpz_t h, byte_string_t bs, params_t params)
//hash a byte_string to an element of Z_p
{
byte_string_t md_value;
crypto_hash(md_value, bs);
mympz_from_hash(h, params->p, md_value);
byte_string_clear(md_value);
}
int FMT_save_params(char *filename, params_t params)
{
int result;
byte_string_t bs;
IBE_serialize_params(bs, params);
result = FMT_save_byte_string(filename, bs);
byte_string_clear(bs);
return result;
}
void IBE_extract_share_byte_string(byte_string_t share, byte_string_t mshare,
byte_string_t id, params_t params)
//extract a private key share from an ID and master share
{
mpz_t y;
int i;
byte_string_t bs1, bs2;
point_t yd;
point_t d;
point_init(yd);
point_init(d);
mpz_init(y);
byte_string_split(bs1, bs2, mshare);
i = int_from_byte_string(bs1);
mympz_set_byte_string(y, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
map_byte_string_to_point(d, id, params);
point_mul(yd, y, d, params->curve);
byte_string_set_int(bs1, i);
byte_string_set_point(bs2, yd);
byte_string_join(share, bs1, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
point_clear(yd);
point_clear(d);
mpz_clear(y);
}
int FMT_load_params(params_t params, char *filename)
{
byte_string_t bs;
int result;
result = FMT_load_byte_string(filename, bs);
if (!result) {
return 0;
}
result = IBE_deserialize_params(params, bs);
byte_string_clear(bs);
return result;
}
int FMT_construct_master(byte_string_t master,
char **fname, int t, params_t params)
{
int i;
/* byte_string_t mshare[t]; */
byte_string_t *mshare;
mshare = (byte_string_t *)malloc((sizeof(byte_string_t) * t));
for (i=0; i<t; i++) {
if (1 != FMT_load_byte_string(fname[i], mshare[i])) {
fprintf(stderr, "error loading %s\n", fname[i]);
return 0;
}
}
IBE_construct_master(master, mshare, params);
for (i=0; i<t; i++) {
byte_string_clear(mshare[i]);
}
free(mshare);
return 1;
}
void FMT_encrypt_stream_array(char **id, int idcount,
FILE *infp, FILE *outfp, params_t params)
{
byte_string_t U, K;
byte_string_t *V;
unsigned char in[crypt_buf_size];
unsigned char *out;
int inl, outl;
crypto_ctx_t ctx;
EVP_ENCODE_CTX mime;
unsigned char data[1024];
int i;
int count;
out = (unsigned char *) alloca(crypt_buf_size + crypto_block_size());
V = (byte_string_t *) alloca(sizeof(byte_string_t) * idcount);
fprintf(outfp, "\n-----BEGIN IBE-----\n");
crypto_generate_key(K);
IBE_hide_key_array(U, V, id, idcount, K, params);
fprintf(outfp, "\nU:\n");
mime_put(U, outfp);
fprintf(outfp, "\n");
for (i=0; i<idcount; i++) {
fprintf(outfp, "\nID:\n");
fprintf(outfp, "%s\n", id[i]);
fprintf(outfp, "\nV:\n");
mime_put(V[i], outfp);
fprintf(outfp, "\n");
byte_string_clear(V[i]);
}
fprintf(outfp, "\nW:\n");
crypto_ctx_init(ctx);
crypto_encrypt_init(ctx, K);
EVP_EncodeInit(&mime);
for (;;) {
inl = fread(in, 1, crypt_buf_size, infp);
if (inl < 0) {
fprintf(stderr, "read error\n");
exit(1);
}
crypto_encrypt_update(ctx, out, &outl, in, inl);
EVP_EncodeUpdate(&mime, data, &count, out, outl);
fwrite(data, 1, count, outfp);
if (feof(infp)) break;
}
crypto_encrypt_final(ctx, out, &outl);
crypto_ctx_clear(ctx);
EVP_EncodeUpdate(&mime, data, &count, out, outl);
fwrite(data, 1, count, outfp);
EVP_EncodeFinal(&mime, data, &count);
fwrite(data, 1, count, outfp);
fprintf(outfp, "\n-----END IBE-----\n");
byte_string_clear(K);
byte_string_clear(U);
}
int main(int argc, char **argv)
{
char defaultcnffile[] = "gen.cnf";
char *cnffile;
CONF_CTX *cnfctx;
int t, n;
int bits, qbits;
char *systemid;
char *paramsfile;
char **sharefile;
char *dfltlist[3];
char dl0[] = "share";
char dl1[] = "share2";
int i;
byte_string_t master;
params_t params;
if (argc < 2) {
cnffile = defaultcnffile;
} else {
cnffile = argv[1];
}
cnfctx = LoadConfig(cnffile);
if (!cnfctx) {
fprintf(stderr, "error opening %s\n", cnffile);
fprintf(stderr, "using default values\n");
cnfctx = constructCTX();
//exit(1);
}
t = GetIntParam(cnfctx, "threshold", 0, 2);
n = GetIntParam(cnfctx, "shares", 0, 2);
bits = GetIntParam(cnfctx, "pbits", 0, 1024);
qbits = GetIntParam(cnfctx, "qbits", 0, 160);
systemid = GetStringParam(cnfctx, "system", 0, "noname");
paramsfile = GetPathParam(cnfctx, "params", 0, "params.txt");
dfltlist[0] = dl0;
dfltlist[1] = dl1;
sharefile = GetListParam(cnfctx, "sharefiles", 0, dfltlist);
printf("Generating IBE public parameters and secret...\n");
printf("Parameters:\n");
printf("system name: %s\n", systemid);
printf("params file: %s\n", paramsfile);
printf("%d-out-of-%d sharing\n", t, n);
printf("%d-bit prime\n", bits);
printf("%d-bit subgroup\n", qbits);
printf("share files:\n");
for (i=0; i<n; i++) {
if (sharefile[i] == NULL) {
fprintf(stderr, "not enough filenames given\n");
exit(1);
}
printf(" %s\n", sharefile[i]);
}
IBE_init();
IBE_setup(params, master, bits, qbits, systemid);
FMT_split_master(sharefile, master, t, n, params);
FMT_save_params(paramsfile, params);
// test it works
if (0) {
byte_string_t key;
//FMT_construct_master(key, sharefile, t);
IBE_extract(key, master, "*****@*****.**", params);
byte_string_clear(key);
}
byte_string_clear(master);
params_clear(params);
IBE_clear();
return 0;
}
int IBE_construct_master(byte_string_t master,
byte_string_t *mshare, params_t params)
//reconstruct the master from master shares
//(shouldn't normally be used since they should never be in one place)
{
int i, j;
int indexi, indexj;
int t = params->sharet;
mpz_t x;
mpz_t y;
mpz_t z;
mpz_t num, denom;
byte_string_t bs1, bs2;
mpz_init(x);
mpz_init(y);
mpz_init(z);
mpz_init(num);
mpz_init(denom);
mpz_set_ui(x, 0);
for (i=0; i<t; i++) {
mpz_set_ui(num, 1);
mpz_set_ui(denom, 1);
byte_string_split(bs1, bs2, mshare[i]);
indexi = int_from_byte_string(bs1);
byte_string_clear(bs1);
mympz_set_byte_string(y, bs2);
byte_string_clear(bs2);
for (j=0; j<t; j++) {
if (j != i) {
byte_string_split(bs1, bs2, mshare[j]);
indexj = int_from_byte_string(bs1);
byte_string_clear(bs1);
byte_string_clear(bs2);
mpz_mul(num, num, params->robustx[indexj]);
mpz_mod(num, num, params->q);
mpz_sub(z, params->robustx[indexj], params->robustx[indexi]);
mpz_mul(denom, denom, z);
mpz_mod(denom, denom, params->q);
}
}
mpz_invert(denom, denom, params->q);
mpz_mul(z, num, denom);
mpz_mod(z, z, params->q);
mpz_mul(z, z, y);
mpz_mod(z, z, params->q);
mpz_add(x, x, z);
if (mpz_cmp(x, params->q) >= 0) {
mpz_sub(x, x, params->q);
}
}
byte_string_set_mpz(master, x);
mpz_clear(x);
mpz_clear(y);
mpz_clear(z);
mpz_clear(num);
mpz_clear(denom);
return 1;
}
void IBE_split_master(byte_string_t *mshare,
byte_string_t master, int t, int n, params_t params)
//split the master key into n pieces
//t of them are required to generate a key
{
mpz_t * poly = malloc(sizeof(mpz_t)*t);
mpz_t *x;
mpz_t *y = malloc(sizeof(mpz_t)*n);
mpz_t z;
mpz_t r;
int i, j;
byte_string_t bs1, bs2;
//start with random polynomial with degree <= t-2
//(in F_q)
//whose constant term = master
mpz_init(r);
mpz_init(poly[0]);
mympz_set_byte_string(poly[0], master);
for (i=1; i<t; i++) {
mpz_init(poly[i]);
mympz_randomm(r, params->q);
mpz_set(poly[i], r);
}
mpz_init(z);
if (0) {
printf("secret poly: ");
for (i=0; i<t; i++) {
printf(" ");
mpz_out_str(NULL, 0, poly[i]);
}
printf("\n");
}
params->robustx = (mpz_t *) malloc(n * sizeof(mpz_t));
params->robustP = (point_t *) malloc(n * sizeof(point_t));
params->sharet = t;
params->sharen = n;
x = params->robustx;
for (i=0; i<n; i++) {
mympz_randomm(r, params->q);
mpz_init(x[i]);
mpz_set(x[i], r);
//Horner's rule
mpz_set_ui(z, 0);
for (j=t-1; j>=0; j--) {
mpz_mul(z, z, x[i]);
mpz_add(z, z, poly[j]);
mpz_mod(z, z, params->q);
}
mpz_init_set(y[i], z);
byte_string_set_int(bs1, i);
byte_string_set_mpz(bs2, z);
byte_string_join(mshare[i], bs1, bs2);
byte_string_clear(bs1);
byte_string_clear(bs2);
}
for (i=0; i<n; i++) {
point_init(params->robustP[i]);
point_mul(params->robustP[i], y[i], params->Ppub, params->curve);
}
for (i=0; i<t; i++) {
mpz_clear(poly[i]);
}
for (i=0; i<n; i++) {
mpz_clear(y[i]);
}
mpz_clear(z);
mpz_clear(r);
}
int IBE_combine(byte_string_t key, byte_string_t *kshare, params_t params)
//reconstruct a key from key shares, or a certificate from certificate shares
{
int i, j;
int indexi, indexj;
point_t yP;
mpz_t num, denom;
mpz_t z;
point_t d;
byte_string_t bs1, bs2;
int *index;
index = (int *) malloc(params->sharet * sizeof(int));
for (i=0; i<params->sharet; i++) {
byte_string_split(bs1, bs2, kshare[i]);
byte_string_clear(bs2);
index[i] = int_from_byte_string(bs1);
byte_string_clear(bs1);
for (j=0; j<i; j++) {
if (index[i] == index[j]) {
return 0;
}
}
}
point_init(yP);
mpz_init(z);
mpz_init(num); mpz_init(denom);
point_init(d);
point_set_O(d);
for (i=0; i<params->sharet; i++) {
byte_string_split(bs1, bs2, kshare[i]);
indexi = index[i];
byte_string_clear(bs1);
point_set_byte_string(yP, bs2);
byte_string_clear(bs2);
mpz_set_ui(num, 1);
mpz_set_ui(denom, 1);
for (j=0; j<params->sharet; j++) {
if (j != i) {
indexj = index[j];
mpz_mul(num, num, params->robustx[indexj]);
mpz_mod(num, num, params->q);
mpz_sub(z, params->robustx[indexj], params->robustx[indexi]);
mpz_mul(denom, denom, z);
mpz_mod(denom, denom, params->q);
}
}
mpz_invert(denom, denom, params->q);
mpz_mul(z, num, denom);
mpz_mod(z, z, params->q);
point_mul(yP, z, yP, params->curve);
point_add(d, d, yP, params->curve);
}
byte_string_set_point(key, d);
point_clear(yP);
mpz_clear(z);
mpz_clear(num); mpz_clear(denom);
point_clear(d);
return 1;
}
int FMT_decrypt_stream(char *id, byte_string_t key,
FILE *infp, FILE *outfp, params_t params)
{
byte_string_t U;
byte_string_t K, V;
crypto_ctx_t ctx;
unsigned char in[crypt_buf_size];
unsigned char out[200]; //TODO: what should this be?
int inl, outl;
unsigned char data[1024];
int count;
EVP_ENCODE_CTX mime;
int result = 0;
char *s, slen;
int status;
advance_to("-----BEGIN IBE-----", infp);
advance_to("U:", infp);
mime_get(U, infp);
slen = strlen(id) + 2;
s = (char *) alloca(sizeof(char) * slen);
for(;;) {
advance_to("ID:", infp);
if (feof(infp)) {
//ID not found
return 0;
}
fgets(s, slen, infp);
if (s[strlen(id)] == '\n') { //correct length?
if (!strncmp(s, id, strlen(id))) { //compares?
break; //email has ID for us
}
}
}
advance_to("V:", infp);
mime_get(V, infp);
status = IBE_reveal_key(K, U, V, key, params);
if (status != 1) {
fprintf(outfp, "WARNING: KMAC MISMATCH. INVALID CIPHERTEXT!\n");
byte_string_clear(V);
byte_string_clear(K);
return result;
}
advance_to("W:", infp);
crypto_ctx_init(ctx);
crypto_decrypt_init(ctx, K);
EVP_DecodeInit(&mime);
for (;;) {
fgets(in, crypt_buf_size, infp);
inl = strlen(in);
if (inl < 0) {
fprintf(stderr, "read error\n");
exit(1);
}
if (inl < 2) break;
EVP_DecodeUpdate(&mime, data, &count, in, inl);
crypto_decrypt_update(ctx, out, &outl, data, count);
fwrite(out, 1, outl, outfp);
}
EVP_DecodeFinal(&mime, data, &count);
crypto_decrypt_update(ctx, out, &outl, data, count);
fwrite(out, 1, outl, outfp);
if (1 != crypto_decrypt_final(ctx, out, &outl)) {
fprintf(outfp, "crypto_decrypt_final() failed!\n");
} else {
result = 1;
}
fwrite(out, 1, outl, outfp);
crypto_ctx_clear(ctx);
byte_string_clear(K);
byte_string_clear(U);
byte_string_clear(V);
return result;
}
