int32_t test(int32_t M,int32_t N,int32_t datasize)
{
int ok = 1, i;
uint8_t * secret = malloc(datasize);
uint8_t *shares[255];
uint8_t *recomb = malloc(datasize);
uint8_t sharenrs[255],newsharenrs[255];// = (uint8_t *)strdup("0124z89abehtr");
gfshare_ctx *G;
gfshare_fill_rand = gfshare_bad_idea_but_fill_rand_using_random;
for (i=0; i<N; i++)
{
sharenrs[i] = i+1;
shares[i] = malloc(datasize);
}
/* Stage 1, make a secret */
for( i = 0; i < datasize; ++i )
secret[i] = (rand() & 0xff00) >> 8;
/* Stage 2, split it N ways with a threshold of M */
G = gfshare_ctx_init_enc( sharenrs, N, M, datasize );
gfshare_ctx_enc_setsecret( G, secret );
for (i=0; i<N; i++)
gfshare_ctx_enc_getshare( G, i, shares[i] );
gfshare_ctx_free( G );
/* Prep the decode shape */
G = gfshare_ctx_init_dec( sharenrs, N, datasize );
memset(newsharenrs,0,N);
int32_t j,r;
for (i=0; i<M; i++)
{
r = rand() % N;
while ( (j= sharenrs[r]) == 0 || newsharenrs[r] != 0 )
r = rand() % N;
newsharenrs[r] = j;
sharenrs[r] = 0;
}
for (i=0; i<N; i++)
{
if ( newsharenrs[i] != 0 )
gfshare_ctx_dec_giveshare( G, i, shares[i] );
//newsharenrs[i] = sharenrs[i];
}
/* Stage 3, attempt a recombination with shares 1 and 2 */
//sharenrs[2] = 0;
gfshare_ctx_dec_newshares( G, newsharenrs );
gfshare_ctx_dec_extract( G, recomb );
for( i = 0; i < datasize; ++i )
if( secret[i] != recomb[i] )
ok = 0;
printf("M.%-3d N.%-3d ok.%d datalen.%d\n",M,N,ok,datasize);
free(recomb), free(secret);
for (i=0; i<N; i++)
free(shares[i]);
return ok!=1;
}
uint8_t *recoverdata(uint8_t *shares[],uint8_t *sharenrs,int32_t M,int32_t datasize,int32_t N)
{
void *G; int32_t i; uint8_t *recover,recovernrs[255];
if ( (recover= calloc(1,datasize)) == 0 )
{
printf("cards777_recover: unexpected out of memory error\n");
return(0);
}
memset(recovernrs,0,sizeof(recovernrs));
for (i=0; i<N; i++)
if ( shares[i] != 0 )
recovernrs[i] = sharenrs[i];
G = gfshare_ctx_init_dec(recovernrs,N,datasize);
for (i=0; i<N; i++)
if ( shares[i] != 0 )
gfshare_ctx_dec_giveshare(G,i,shares[i]);
gfshare_ctx_dec_newshares(G,recovernrs);
gfshare_ctx_dec_extract(G,recover);
gfshare_ctx_free(G);
return(recover);
}
PPH_ERROR pph_unlock_password_data(pph_context *ctx,unsigned int username_count,
const uint8 *usernames[],
unsigned int username_lengths[],
const uint8 *passwords[]){
uint8 share_numbers[MAX_NUMBER_OF_SHARES];
gfshare_ctx *G;
unsigned int i;
uint8 secret[SHARE_LENGTH];
uint8 salted_password[MAX_USERNAME_LENGTH+MAX_SALT_LENGTH];
uint8 estimated_digest[DIGEST_LENGTH];
uint8 estimated_share[SHARE_LENGTH];
pph_entry *entry;
pph_account_node *current_user;
//sanitize the data.
if(ctx == NULL || usernames == NULL || passwords == NULL ||
username_lengths == NULL){
return PPH_BAD_PTR;
}
if(username_count < ctx->threshold){
return PPH_ACCOUNT_IS_INVALID;
}
// initialize the share numbers
for(i=0;i<MAX_NUMBER_OF_SHARES;i++){
share_numbers[i] = 0;
}
// initialize a recombination context
G = gfshare_ctx_init_dec( share_numbers, MAX_NUMBER_OF_SHARES-1,
SHARE_LENGTH-ctx->partial_bytes);
// traverse our possible users
current_user=ctx->account_data;
while(current_user!=NULL){
// check if each of the provided users is inside the context. We traverse
// our user list inside the while, and compare against the provided users
// inside this for loop.
for(i = 0; i<username_count;i++){
//compare the proposed against existing users.
if(username_lengths[i] == current_user->account.username_length &&
(!memcmp(usernames[i],current_user->account.username,
current_user->account.username_length))){
// this is an existing user
entry = current_user->account.entries;
// check if he is a threshold account.
if(entry->share_number != 0){
// if he is a threshold account, we must attempt to reconstruct the
// shares using their information, traverse his entries
while(entry!=NULL){
// calulate the digest given the password.
memcpy(salted_password,entry->salt,entry->salt_length);
memcpy(salted_password+entry->salt_length, passwords[i],
entry->password_length);
_calculate_digest(estimated_digest,salted_password,
MAX_SALT_LENGTH + current_user->account.entries->password_length);
// xor the obtained digest with the polyhashed value to obtain
// our share.
_xor_share_with_digest(estimated_share,entry->polyhashed_value,
estimated_digest,SHARE_LENGTH-ctx->partial_bytes);
// give share to the recombinator.
share_numbers[entry->share_number] = entry->share_number+1;
gfshare_ctx_dec_giveshare(G, entry->share_number,estimated_share);
// move to the next entry.
entry = entry->next;
}
}
}
}
current_user = current_user->next;
}
// now we attempt to recombine the secret, we have given him all of the
// obtained shares.
gfshare_ctx_dec_newshares(G, share_numbers);
gfshare_ctx_dec_extract(G, secret);
// verify that we got a proper secret back.
if(check_pph_secret(secret, SIGNATURE_RANDOM_BYTE_LENGTH-ctx->partial_bytes,
SIGNATURE_HASH_BYTE_LENGTH) != PPH_ERROR_OK){
return PPH_ACCOUNT_IS_INVALID;
}
// else, we have a correct secret and we will copy it back to the provided
// context.
if(ctx->secret == NULL){
ctx->secret = calloc(sizeof(ctx->secret),SHARE_LENGTH-ctx->partial_bytes);
}
memcpy(ctx->secret,secret,SHARE_LENGTH-ctx->partial_bytes);
// if the share context is not initialized, initialize one with the
// information we have about our context.
if(ctx->share_context == NULL){
for(i=0;i<MAX_NUMBER_OF_SHARES;i++){
share_numbers[i]=(unsigned char)i+1;
}
ctx->share_context = gfshare_ctx_init_enc( share_numbers,
MAX_NUMBER_OF_SHARES-1,
ctx->threshold,
SHARE_LENGTH-ctx->partial_bytes);
}
// we have an initialized share context, we set the recombined secret to it
// and set the unlock flag to one so it is ready to use.
gfshare_ctx_enc_setsecret(ctx->share_context, ctx->secret);
ctx->is_unlocked = true;
ctx->AES_key = ctx->secret;
return PPH_ERROR_OK;
}