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use core::{convert::Infallible, marker::PhantomData, ptr::copy_nonoverlapping};
use crate::rsa::{
implement_op,
Multi,
Rsa,
RsaMode,
RsaModularExponentiation,
RsaModularMultiplication,
RsaMultiplication,
};
impl<'d> Rsa<'d> {
/// After the RSA Accelerator is released from reset, the memory blocks
/// needs to be initialized, only after that peripheral should be used.
/// This function would return without an error if the memory is initialized
pub fn ready(&mut self) -> nb::Result<(), Infallible> {
if self.rsa.clean().read().clean().bit_is_clear() {
return Err(nb::Error::WouldBlock);
}
Ok(())
}
/// Enables/disables rsa interrupt, when enabled rsa perpheral would
/// generate an interrupt when a operation is finished.
pub fn enable_disable_interrupt(&mut self, enable: bool) {
match enable {
true => self
.rsa
.interrupt_ena()
.write(|w| w.interrupt_ena().set_bit()),
false => self
.rsa
.interrupt_ena()
.write(|w| w.interrupt_ena().clear_bit()),
}
}
fn write_mode(&mut self, mode: u32) {
self.rsa.mode().write(|w| unsafe { w.bits(mode) });
}
/// Enables/disables search acceleration, when enabled it would increases
/// the performance of modular exponentiation by discarding the
/// exponent's bits before the most significant set bit. Note: this might
/// affect the security, for more info refer 18.3.4 of <https://www.espressif.com/sites/default/files/documentation/esp32-c6_technical_reference_manual_en.pdf>
pub fn enable_disable_search_acceleration(&mut self, enable: bool) {
match enable {
true => self
.rsa
.search_enable()
.write(|w| w.search_enable().set_bit()),
false => self
.rsa
.search_enable()
.write(|w| w.search_enable().clear_bit()),
}
}
pub(super) fn is_search_enabled(&mut self) -> bool {
self.rsa.search_enable().read().search_enable().bit_is_set()
}
pub(super) fn write_search_position(&mut self, search_position: u32) {
self.rsa
.search_pos()
.write(|w| unsafe { w.bits(search_position) });
}
/// Enables/disables constant time acceleration, when enabled it would
/// increases the performance of modular exponentiation by simplifying
/// the calculation concerning the 0 bits of the exponent i.e. lesser the
/// hamming weight, greater the performance. Note : this might affect
/// the security, for more info refer 18.3.4 of <https://www.espressif.com/sites/default/files/documentation/esp32-c6_technical_reference_manual_en.pdf>
pub fn enable_disable_constant_time_acceleration(&mut self, enable: bool) {
match enable {
true => self
.rsa
.constant_time()
.write(|w| w.constant_time().clear_bit()),
false => self
.rsa
.constant_time()
.write(|w| w.constant_time().set_bit()),
}
}
pub(super) fn write_modexp_start(&mut self) {
self.rsa
.modexp_start()
.write(|w| w.modexp_start().set_bit());
}
pub(super) fn write_multi_start(&mut self) {
self.rsa.mult_start().write(|w| w.mult_start().set_bit());
}
fn write_modmulti_start(&mut self) {
self.rsa
.modmult_start()
.write(|w| w.modmult_start().set_bit());
}
pub(super) fn clear_interrupt(&mut self) {
self.rsa
.clear_interrupt()
.write(|w| w.clear_interrupt().set_bit());
}
pub(super) fn is_idle(&mut self) -> bool {
self.rsa.idle().read().idle().bit_is_set()
}
unsafe fn write_multi_operand_b<const N: usize>(&mut self, operand_b: &[u32; N]) {
copy_nonoverlapping(operand_b.as_ptr(), self.rsa.z_mem(0).as_ptr().add(N), N);
}
}
pub mod operand_sizes {
//! Marker types for the operand sizes
use paste::paste;
use super::{implement_op, Multi, RsaMode};
implement_op!(
(32, multi),
(64, multi),
(96, multi),
(128, multi),
(160, multi),
(192, multi),
(224, multi),
(256, multi),
(288, multi),
(320, multi),
(352, multi),
(384, multi),
(416, multi),
(448, multi),
(480, multi),
(512, multi),
(544, multi),
(576, multi),
(608, multi),
(640, multi),
(672, multi),
(704, multi),
(736, multi),
(768, multi),
(800, multi),
(832, multi),
(864, multi),
(896, multi),
(928, multi),
(960, multi),
(992, multi),
(1024, multi),
(1056, multi),
(1088, multi),
(1120, multi),
(1152, multi),
(1184, multi),
(1216, multi),
(1248, multi),
(1280, multi),
(1312, multi),
(1344, multi),
(1376, multi),
(1408, multi),
(1440, multi),
(1472, multi),
(1504, multi),
(1536, multi),
(1568, multi),
(1600, multi),
(1632, multi),
(1664, multi),
(1696, multi),
(1728, multi),
(1760, multi),
(1792, multi),
(1824, multi),
(1856, multi),
(1888, multi),
(1920, multi),
(1952, multi),
(1984, multi),
(2016, multi),
(2048, multi)
);
implement_op!(
(2080),
(2112),
(2144),
(2176),
(2208),
(2240),
(2272),
(2304),
(2336),
(2368),
(2400),
(2432),
(2464),
(2496),
(2528),
(2560),
(2592),
(2624),
(2656),
(2688),
(2720),
(2752),
(2784),
(2816),
(2848),
(2880),
(2912),
(2944),
(2976),
(3008),
(3040),
(3072),
(3104),
(3136),
(3168),
(3200),
(3232),
(3264),
(3296),
(3328),
(3360),
(3392),
(3424),
(3456),
(3488),
(3520),
(3552),
(3584),
(3616),
(3648),
(3680),
(3712),
(3744),
(3776),
(3808),
(3840),
(3872),
(3904),
(3936),
(3968),
(4000),
(4032),
(4064),
(4096)
);
}
impl<'a, 'd, T: RsaMode, const N: usize> RsaModularExponentiation<'a, 'd, T>
where
T: RsaMode<InputType = [u32; N]>,
{
/// Creates an Instance of `RsaModularExponentiation`.
/// `m_prime` could be calculated using `-(modular multiplicative inverse of
/// modulus) mod 2^32`, for more information check 19.3.1 in the
/// <https://www.espressif.com/sites/default/files/documentation/esp32-c3_technical_reference_manual_en.pdf>
pub fn new(
rsa: &'a mut Rsa<'d>,
exponent: &T::InputType,
modulus: &T::InputType,
m_prime: u32,
) -> Self {
Self::set_mode(rsa);
unsafe {
rsa.write_operand_b(exponent);
rsa.write_modulus(modulus);
}
rsa.write_mprime(m_prime);
if rsa.is_search_enabled() {
rsa.write_search_position(Self::find_search_pos(exponent));
}
Self {
rsa,
phantom: PhantomData,
}
}
fn find_search_pos(exponent: &T::InputType) -> u32 {
for (i, byte) in exponent.iter().rev().enumerate() {
if *byte == 0 {
continue;
}
return (exponent.len() * 32) as u32 - (byte.leading_zeros() + i as u32 * 32) - 1;
}
0
}
pub(super) fn set_mode(rsa: &mut Rsa) {
rsa.write_mode((N - 1) as u32)
}
pub(super) fn set_start(&mut self) {
self.rsa.write_modexp_start();
}
}
impl<'a, 'd, T: RsaMode, const N: usize> RsaModularMultiplication<'a, 'd, T>
where
T: RsaMode<InputType = [u32; N]>,
{
/// Creates an Instance of `RsaModularMultiplication`.
/// `m_prime` could be calculated using `-(modular multiplicative inverse of
/// modulus) mod 2^32`, for more information check 19.3.1 in the
/// <https://www.espressif.com/sites/default/files/documentation/esp32-c3_technical_reference_manual_en.pdf>
pub fn new(
rsa: &'a mut Rsa<'d>,
operand_a: &T::InputType,
operand_b: &T::InputType,
modulus: &T::InputType,
m_prime: u32,
) -> Self {
Self::write_mode(rsa);
rsa.write_mprime(m_prime);
unsafe {
rsa.write_modulus(modulus);
rsa.write_operand_a(operand_a);
rsa.write_operand_b(operand_b);
}
Self {
rsa,
phantom: PhantomData,
}
}
fn write_mode(rsa: &mut Rsa) {
rsa.write_mode((N - 1) as u32)
}
/// Starts the modular multiplication operation. `r` could be calculated
/// using `2 ^ ( bitlength * 2 ) mod modulus`, for more information
/// check 19.3.1 in the <https://www.espressif.com/sites/default/files/documentation/esp32-c3_technical_reference_manual_en.pdf>
pub fn start_modular_multiplication(&mut self, r: &T::InputType) {
unsafe {
self.rsa.write_r(r);
}
self.set_start();
}
fn set_start(&mut self) {
self.rsa.write_modmulti_start();
}
}
impl<'a, 'd, T: RsaMode + Multi, const N: usize> RsaMultiplication<'a, 'd, T>
where
T: RsaMode<InputType = [u32; N]>,
{
/// Creates an Instance of `RsaMultiplication`.
pub fn new(rsa: &'a mut Rsa<'d>, operand_a: &T::InputType) -> Self {
Self::set_mode(rsa);
unsafe {
rsa.write_operand_a(operand_a);
}
Self {
rsa,
phantom: PhantomData,
}
}
/// Starts the multiplication operation.
pub fn start_multiplication(&mut self, operand_b: &T::InputType) {
unsafe {
self.rsa.write_multi_operand_b(operand_b);
}
self.set_start();
}
pub(super) fn set_mode(rsa: &mut Rsa) {
rsa.write_mode((N * 2 - 1) as u32)
}
pub(super) fn set_start(&mut self) {
self.rsa.write_multi_start();
}
}