static void ccn_mod_521(cczp_const_t zp, cc_unit *r, const cc_unit *a, CC_UNUSED cc_ws_t ws) {
cc_assert(cczp_n(zp) == CCN521_N);
cc_unit t[CCN521_N];
cc_unit t2[CCN521_N];
cc_unit *select[2] __attribute__((aligned(16))) ={t,t2};
cc_unit borrow;
#if CCN_UNIT_SIZE == 1
ccn_shift_right(CCN521_N - 1, t2, &a[CCN521_N - 1], 1); // r = a521,...,a1041
t2[CCN521_N - 1] += a[CCN521_N - 1] & CC_UNIT_C(1);
t2[CCN521_N - 1] += ccn_add(CCN521_N - 1,t2,t2,a);
#else
ccn_shift_right(CCN521_N, t2, &a[CCN512_N], 9); // r = a521,...,a1041
t2[CCN512_N] += a[CCN512_N] & CC_UNIT_C(0x1ff); // r += (a512,...,a520)*2^512
t2[CCN512_N] += ccn_add(CCN512_N,t2,t2,a); // r += a0,...,a511
#endif
borrow=ccn_sub(CCN521_N, t, t2, cczp_prime(zp));
ccn_set(CCN521_N,r,select[borrow]);
}
void cczp_div2(cczp_const_short_t zp, cc_unit *r, const cc_unit *x) {
if (x[0] & 1) {
/* x is odd r = (x + p) >> 1 */
cc_unit carry = ccn_add(cczp_n(zp), r, x, cczp_prime(zp));
ccn_shift_right(cczp_n(zp), r, r, 1);
r[cczp_n(zp) - 1] |= carry << (CCN_UNIT_BITS - 1);
} else {
/* x is even r = x >> 1 */
ccn_shift_right(cczp_n(zp), r, x, 1);
}
}
static void ccn_mod_384(cczp_const_t zp, cc_unit *r, const cc_unit *a, CC_UNUSED cc_ws_t ws) {
cc_assert(cczp_n(zp) == CCN384_N);
cc_unit s1[CCN384_N] = { ccn384_32( Anil, Anil, Anil, Anil, Anil, A(23), A(22), A(21), Anil, Anil, Anil, Anil) };
//cc_unit s2[CCN384_N] = { ccn384_32( A(23), A(22), A(21), A(20), A(19), A(18), A(17), A(16), A(15), A(14), A(13), A(12)) };
cc_unit s3[CCN384_N] = { ccn384_32( A(20), A(19), A(18), A(17), A(16), A(15), A(14), A(13), A(12), A(23), A(22), A(21)) };
cc_unit s4[CCN384_N] = { ccn384_32( A(19), A(18), A(17), A(16), A(15), A(14), A(13), A(12), A(20), Anil, A(23), Anil) };
cc_unit s5[CCN384_N] = { ccn384_32( Anil, Anil, Anil, Anil, A(23), A(22), A(21), A(20), Anil, Anil, Anil, Anil) };
cc_unit s6[CCN384_N] = { ccn384_32( Anil, Anil, Anil, Anil, Anil, Anil, A(23), A(22), A(21), Anil, Anil, A(20)) };
cc_unit d1[CCN384_N] = { ccn384_32( A(22), A(21), A(20), A(19), A(18), A(17), A(16), A(15), A(14), A(13), A(12), A(23)) };
cc_unit d2[CCN384_N] = { ccn384_32( Anil, Anil, Anil, Anil, Anil, Anil, Anil, A(23), A(22), A(21), A(20), Anil) };
cc_unit d3[CCN384_N] = { ccn384_32( Anil, Anil, Anil, Anil, Anil, Anil, Anil, A(23), A(23), Anil, Anil, Anil) };
cc_unit *select[2] __attribute__((aligned(16))) ={s1,s3};
cc_unit carry,carry_mask;
ccn_add(ccn_nof(160)+1, d2, d2, d3); // smaller size and no carry possible
ccn_add(ccn_nof(224)+1, s1, s1, s1); // smaller size and no carry possible, alternatively cc_shiftl(s1, 1) but add is currently faster.
ccn_add(ccn_nof(256)+1, s5, s5, s1); // smaller size and no carry possible
ccn_add(ccn_nof(256)+1, s5, s5, s6); // smaller size and no carry possible
carry = ccn_add(CCN384_N, r, a, &a[CCN384_N]);
carry += ccn_add(CCN384_N, r, r, s3);
carry += ccn_add(CCN384_N, r, r, s4);
carry += ccn_add(CCN384_N, r, r, s5);
carry -= ccn_sub(CCN384_N, d1, cczp_prime(zp), d1);
carry += ccn_add(CCN384_N, r, r, d1);
carry -= ccn_sub(CCN384_N, s3, r, d2);
/* Reduce r mod p384 by subtraction of up to four multiples of p384. */
carry_mask=CC_CARRY_3BITS(carry);
carry -= (carry_mask & ccn_sub(CCN384_N,select[carry_mask],s3,cczp_prime(zp)));
carry_mask=CC_CARRY_2BITS(carry);
carry -= (carry_mask & ccn_sub(CCN384_N,select[carry_mask],s3,cczp_prime(zp)));
carry_mask=CC_CARRY_2BITS(carry);
carry -= (carry_mask & ccn_sub(CCN384_N,select[carry_mask],s3,cczp_prime(zp)));
carry ^= ccn_sub(CCN384_N,s1,s3,cczp_prime(zp));
ccn_set(CCN384_N,r,select[carry]);
/* Sanity for debug */
cc_assert(ccn_cmp(CCN384_N, r, cczp_prime(zp)) < 0);
}
int p12_pbe_gen(CFStringRef passphrase, uint8_t *salt_ptr, size_t salt_length,
unsigned iter_count, P12_PBE_ID pbe_id, uint8_t *data, size_t length)
{
unsigned int hash_blocksize = CC_SHA1_BLOCK_BYTES;
unsigned int hash_outputsize = CC_SHA1_DIGEST_LENGTH;
if (!passphrase)
return -1;
/* generate diversifier block */
unsigned char diversifier[hash_blocksize];
memset(diversifier, pbe_id, sizeof(diversifier));
/* convert passphrase to BE UTF16 and append double null */
CFDataRef passphrase_be_unicode = CFStringCreateExternalRepresentation(kCFAllocatorDefault, passphrase, kCFStringEncodingUTF16BE, '\0');
if (!passphrase_be_unicode)
return -1;
uint8_t null_termination[2] = { 0, 0 };
CFMutableDataRef passphrase_be_unicode_null_term = CFDataCreateMutableCopy(NULL, 0, passphrase_be_unicode);
CFRelease(passphrase_be_unicode);
if (!passphrase_be_unicode_null_term)
return -1;
CFDataAppendBytes(passphrase_be_unicode_null_term, null_termination, sizeof(null_termination));
/* generate passphrase block */
uint8_t *passphrase_data = NULL;
size_t passphrase_data_len = 0;
size_t passphrase_length = CFDataGetLength(passphrase_be_unicode_null_term);
const unsigned char *passphrase_ptr = CFDataGetBytePtr(passphrase_be_unicode_null_term);
passphrase_data = concatenate_to_blocksize(passphrase_ptr, passphrase_length, hash_blocksize, &passphrase_data_len);
CFRelease(passphrase_be_unicode_null_term);
if (!passphrase_data)
return -1;
/* generate salt block */
uint8_t *salt_data = NULL;
size_t salt_data_len = 0;
if (salt_length)
salt_data = concatenate_to_blocksize(salt_ptr, salt_length, hash_blocksize, &salt_data_len);
if (!salt_data)
return -1;
/* generate S||P block */
size_t I_length = salt_data_len + passphrase_data_len;
uint8_t *I_data = malloc(I_length);
if (!I_data)
return -1;
memcpy(I_data + 0, salt_data, salt_data_len);
memcpy(I_data + salt_data_len, passphrase_data, passphrase_data_len);
free(salt_data);
free(passphrase_data);
/* round up output buffer to multiple of hash block size and allocate */
size_t hash_output_blocks = (length + hash_outputsize - 1) / hash_outputsize;
size_t temp_buf_size = hash_output_blocks * hash_outputsize;
uint8_t *temp_buf = malloc(temp_buf_size);
uint8_t *cursor = temp_buf;
if (!temp_buf)
return -1;
/* 64 bits cast(s): worst case here is we dont hash all the data and incorectly derive the wrong key,
when the passphrase + salt are over 2^32 bytes long */
/* loop over output in hash_output_size increments */
while (cursor < temp_buf + temp_buf_size) {
CC_SHA1_CTX ctx;
CC_SHA1_Init(&ctx);
CC_SHA1_Update(&ctx, diversifier, (CC_LONG)sizeof(diversifier));
assert(I_length<=UINT32_MAX); /* debug check. Correct as long as CC_LONG is uint32_t */
CC_SHA1_Update(&ctx, I_data, (CC_LONG)I_length);
CC_SHA1_Final(cursor, &ctx);
/* run block through SHA-1 for iteration count */
unsigned int i;
for (i = 1; /*first round done above*/ i < iter_count; i++)
CC_SHA1(cursor, hash_outputsize, cursor);
/*
* b) Concatenate copies of A[i] to create a string B of
* length v bits (the final copy of A[i]i may be truncated
* to create B).
*/
size_t A_i_len = 0;
uint8_t *A_i = concatenate_to_blocksize(cursor,
hash_outputsize, hash_blocksize, &A_i_len);
if (!A_i)
return -1;
/*
* c) Treating I as a concatenation I[0], I[1], ...,
* I[k-1] of v-bit blocks, where k = ceil(s/v) + ceil(p/v),
* modify I by setting I[j]=(I[j]+B+1) mod (2 ** v)
* for each j.
*/
/* tmp1 = B+1 */
const cc_size tmp_n = ccn_nof_size(A_i_len + 1) > ccn_nof_size(hash_blocksize) ? ccn_nof_size(A_i_len + 1) : ccn_nof_size(hash_blocksize);
cc_unit tmp1[tmp_n];
ccn_read_uint(tmp_n, tmp1, A_i_len, A_i);
ccn_add1(tmp_n, tmp1, tmp1, 1);
free(A_i);
cc_unit tmp2[tmp_n];
unsigned int j;
for (j = 0; j < I_length; j+=hash_blocksize) {
/* tempg = I[j]; */
ccn_read_uint(tmp_n, tmp2, hash_blocksize, I_data + j);
/* tempg += tmp1 */
ccn_add(tmp_n, tmp2, tmp2, tmp1);
/* I[j] = tempg mod 2**v
Just clear all the high bits above 2**v
In practice at most it rolled over by 1 bit, since all we did was add so
we should only clear one bit at most.
*/
size_t bitSize;
const size_t hash_blocksize_bits = hash_blocksize * 8;
while ((bitSize = ccn_bitlen(tmp_n, tmp2)) > hash_blocksize_bits)
{
ccn_set_bit(tmp2, bitSize - 1, 0);
}
ccn_write_uint_padded(tmp_n, tmp2, hash_blocksize, I_data + j);
}
cursor += hash_outputsize;
}
/*
* 7. Concatenate A[1], A[2], ..., A[c] together to form a
* pseudo-random bit string, A.
*
* 8. Use the first n bits of A as the output of this entire
* process.
*/
memmove(data, temp_buf, length);
free(temp_buf);
free(I_data);
return 0;
}
