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LibCrypto: Move all elliptic curve private methods into .cpp

All the elliptic curve implementations had a long list of private
methods which were all stored in a single .cpp file. Now we simply use
static methods instead.
This commit is contained in:
Michiel Visser 2022-03-18 19:18:29 +01:00 committed by Ali Mohammad Pur
parent 596391a4ee
commit e07ec02470
6 changed files with 171 additions and 220 deletions

View file

@ -11,19 +11,24 @@
namespace Crypto::Curves {
void X448::import_state(u32* state, ReadonlyBytes data)
static constexpr u16 BITS = 448;
static constexpr u8 BYTES = 56;
static constexpr u8 WORDS = 14;
static constexpr u32 A24 = 39082;
static void import_state(u32* state, ReadonlyBytes data)
{
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
u32 value = ByteReader::load32(data.offset_pointer(sizeof(u32) * i));
state[i] = AK::convert_between_host_and_little_endian(value);
}
}
ErrorOr<ByteBuffer> X448::export_state(u32* data)
static ErrorOr<ByteBuffer> export_state(u32* data)
{
auto buffer = TRY(ByteBuffer::create_uninitialized(X448::BYTES));
auto buffer = TRY(ByteBuffer::create_uninitialized(BYTES));
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
u32 value = AK::convert_between_host_and_little_endian(data[i]);
ByteReader::store(buffer.offset_pointer(sizeof(u32) * i), value);
}
@ -31,50 +36,74 @@ ErrorOr<ByteBuffer> X448::export_state(u32* data)
return buffer;
}
void X448::select(u32* state, u32* a, u32* b, u32 condition)
static void select(u32* state, u32* a, u32* b, u32 condition)
{
// If B < (2^448 - 2^224 + 1) then R = B, else R = A
u32 mask = condition - 1;
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
state[i] = (a[i] & mask) | (b[i] & ~mask);
}
}
void X448::set(u32* state, u32 value)
static void set(u32* state, u32 value)
{
state[0] = value;
for (auto i = 1; i < X448::WORDS; i++) {
for (auto i = 1; i < WORDS; i++) {
state[i] = 0;
}
}
void X448::copy(u32* state, u32* value)
static void copy(u32* state, u32* value)
{
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
state[i] = value[i];
}
}
void X448::conditional_swap(u32* first, u32* second, u32 condition)
static void conditional_swap(u32* first, u32* second, u32 condition)
{
u32 mask = ~condition + 1;
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
u32 temp = mask & (first[i] ^ second[i]);
first[i] ^= temp;
second[i] ^= temp;
}
}
void X448::modular_multiply_single(u32* state, u32* first, u32 second)
static void modular_reduce(u32* state, u32* data, u32 a_high)
{
u64 temp = 1;
u32 other[WORDS];
// Compute B = A - (2^448 - 2^224 - 1)
for (auto i = 0; i < WORDS / 2; i++) {
temp += data[i];
other[i] = temp & 0xFFFFFFFF;
temp >>= 32;
}
temp += 1;
for (auto i = 7; i < WORDS; i++) {
temp += data[i];
other[i] = temp & 0xFFFFFFFF;
temp >>= 32;
}
auto condition = (a_high + (u32)temp - 1) & 1;
select(state, other, data, condition);
}
static void modular_multiply_single(u32* state, u32* first, u32 second)
{
// Compute R = (A * B) mod p
u64 temp = 0;
u64 carry = 0;
u32 output[X448::WORDS];
u32 output[WORDS];
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
temp += (u64)first[i] * second;
output[i] = temp & 0xFFFFFFFF;
temp >>= 32;
@ -82,14 +111,14 @@ void X448::modular_multiply_single(u32* state, u32* first, u32 second)
// Fast modular reduction
carry = temp;
for (auto i = 0; i < X448::WORDS / 2; i++) {
for (auto i = 0; i < WORDS / 2; i++) {
temp += output[i];
output[i] = temp & 0xFFFFFFFF;
temp >>= 32;
}
temp += carry;
for (auto i = X448::WORDS / 2; i < X448::WORDS; i++) {
for (auto i = WORDS / 2; i < WORDS; i++) {
temp += output[i];
output[i] = temp & 0xFFFFFFFF;
temp >>= 32;
@ -98,22 +127,16 @@ void X448::modular_multiply_single(u32* state, u32* first, u32 second)
modular_reduce(state, output, (u32)temp);
}
void X448::modular_square(u32* state, u32* value)
{
// Compute R = (A ^ 2) mod p
modular_multiply(state, value, value);
}
void X448::modular_multiply(u32* state, u32* first, u32* second)
static void modular_multiply(u32* state, u32* first, u32* second)
{
// Compute R = (A * B) mod p
u64 temp = 0;
u64 carry = 0;
u32 output[X448::WORDS * 2];
u32 output[WORDS * 2];
// Comba's method
for (auto i = 0; i < X448::WORDS * 2; i++) {
for (auto i = 0; i < WORDS * 2; i++) {
if (i < 14) {
for (auto j = 0; j <= i; j++) {
temp += (u64)first[j] * second[i - j];
@ -121,7 +144,7 @@ void X448::modular_multiply(u32* state, u32* first, u32* second)
temp &= 0xFFFFFFFF;
}
} else {
for (auto j = i - 13; j < X448::WORDS; j++) {
for (auto j = i - 13; j < WORDS; j++) {
temp += (u64)first[j] * second[i - j];
carry += temp >> 32;
temp &= 0xFFFFFFFF;
@ -135,7 +158,7 @@ void X448::modular_multiply(u32* state, u32* first, u32* second)
// Fast modular reduction (first pass)
temp = 0;
for (auto i = 0; i < X448::WORDS / 2; i++) {
for (auto i = 0; i < WORDS / 2; i++) {
temp += output[i];
temp += output[i + 14];
temp += output[i + 21];
@ -143,7 +166,7 @@ void X448::modular_multiply(u32* state, u32* first, u32* second)
temp >>= 32;
}
for (auto i = X448::WORDS / 2; i < X448::WORDS; i++) {
for (auto i = WORDS / 2; i < WORDS; i++) {
temp += output[i];
temp += output[i + 7];
temp += output[i + 14];
@ -154,14 +177,14 @@ void X448::modular_multiply(u32* state, u32* first, u32* second)
// Fast modular reduction (second pass)
carry = temp;
for (auto i = 0; i < X448::WORDS / 2; i++) {
for (auto i = 0; i < WORDS / 2; i++) {
temp += output[i];
output[i] = temp & 0xFFFFFFFF;
temp >>= 32;
}
temp += carry;
for (auto i = X448::WORDS / 2; i < X448::WORDS; i++) {
for (auto i = WORDS / 2; i < WORDS; i++) {
temp += output[i];
output[i] = temp & 0xFFFFFFFF;
temp >>= 32;
@ -170,12 +193,18 @@ void X448::modular_multiply(u32* state, u32* first, u32* second)
modular_reduce(state, output, (u32)temp);
}
void X448::modular_add(u32* state, u32* first, u32* second)
static void modular_square(u32* state, u32* value)
{
// Compute R = (A ^ 2) mod p
modular_multiply(state, value, value);
}
static void modular_add(u32* state, u32* first, u32* second)
{
u64 temp = 0;
// Compute R = A + B
for (auto i = 0; i < X448::WORDS; i++) {
for (auto i = 0; i < WORDS; i++) {
temp += first[i];
temp += second[i];
state[i] = temp & 0xFFFFFFFF;
@ -185,7 +214,7 @@ void X448::modular_add(u32* state, u32* first, u32* second)
modular_reduce(state, state, (u32)temp);
}
void X448::modular_subtract(u32* state, u32* first, u32* second)
static void modular_subtract(u32* state, u32* first, u32* second)
{
i64 temp = -1;
@ -211,31 +240,7 @@ void X448::modular_subtract(u32* state, u32* first, u32* second)
modular_reduce(state, state, (u32)temp);
}
void X448::modular_reduce(u32* state, u32* data, u32 a_high)
{
u64 temp = 1;
u32 other[X448::WORDS];
// Compute B = A - (2^448 - 2^224 - 1)
for (auto i = 0; i < X448::WORDS / 2; i++) {
temp += data[i];
other[i] = temp & 0xFFFFFFFF;
temp >>= 32;
}
temp += 1;
for (auto i = 7; i < X448::WORDS; i++) {
temp += data[i];
other[i] = temp & 0xFFFFFFFF;
temp >>= 32;
}
auto condition = (a_high + (u32)temp - 1) & 1;
select(state, other, data, condition);
}
void X448::to_power_of_2n(u32* state, u32* value, u8 n)
static void to_power_of_2n(u32* state, u32* value, u8 n)
{
// Compute R = (A ^ (2^n)) mod p
modular_square(state, value);
@ -244,11 +249,11 @@ void X448::to_power_of_2n(u32* state, u32* value, u8 n)
}
}
void X448::modular_multiply_inverse(u32* state, u32* value)
static void modular_multiply_inverse(u32* state, u32* value)
{
// Compute R = A^-1 mod p
u32 u[X448::WORDS];
u32 v[X448::WORDS];
u32 u[WORDS];
u32 v[WORDS];
modular_square(u, value);
modular_multiply(u, u, value);
@ -299,14 +304,14 @@ ErrorOr<ByteBuffer> X448::generate_public_key(ReadonlyBytes a)
// https://datatracker.ietf.org/doc/html/rfc7748#section-5
ErrorOr<ByteBuffer> X448::compute_coordinate(ReadonlyBytes input_k, ReadonlyBytes input_u)
{
u32 k[X448::WORDS] {};
u32 u[X448::WORDS] {};
u32 x1[X448::WORDS] {};
u32 x2[X448::WORDS] {};
u32 z1[X448::WORDS] {};
u32 z2[X448::WORDS] {};
u32 t1[X448::WORDS] {};
u32 t2[X448::WORDS] {};
u32 k[WORDS] {};
u32 u[WORDS] {};
u32 x1[WORDS] {};
u32 x2[WORDS] {};
u32 z1[WORDS] {};
u32 z2[WORDS] {};
u32 t1[WORDS] {};
u32 t2[WORDS] {};
// Copy input to internal state
import_state(k, input_k);
@ -329,7 +334,7 @@ ErrorOr<ByteBuffer> X448::compute_coordinate(ReadonlyBytes input_k, ReadonlyByte
// Montgomery ladder
u32 swap = 0;
for (auto i = X448::BITS - 1; i >= 0; i--) {
for (auto i = BITS - 1; i >= 0; i--) {
u32 b = (k[i / 32] >> (i % 32)) & 1;
conditional_swap(x1, x2, swap ^ b);