esp_hal/rsa/
esp32sX.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
use core::convert::Infallible;

use crate::rsa::{
    implement_op,
    Multi,
    Rsa,
    RsaMode,
    RsaModularExponentiation,
    RsaModularMultiplication,
    RsaMultiplication,
};

impl<Dm: crate::DriverMode> Rsa<'_, Dm> {
    /// 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.regs().clean().read().clean().bit_is_clear() {
            return Err(nb::Error::WouldBlock);
        }
        Ok(())
    }

    /// Enables/disables rsa interrupt.
    ///
    /// When enabled rsa peripheral would generate an interrupt when a operation
    /// is finished.
    pub fn enable_disable_interrupt(&mut self, enable: bool) {
        self.regs().int_ena().write(|w| w.int_ena().bit(enable));
    }

    fn write_mode(&mut self, mode: u32) {
        self.regs().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 decrease security.
    ///
    /// For more information refer to 20.3.4 of <https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf>.
    pub fn enable_disable_search_acceleration(&mut self, enable: bool) {
        self.regs()
            .search_enable()
            .write(|w| w.search_enable().bit(enable));
    }

    /// Checks if the search functionality is enabled in the RSA hardware.
    pub(super) fn is_search_enabled(&mut self) -> bool {
        self.regs()
            .search_enable()
            .read()
            .search_enable()
            .bit_is_set()
    }

    /// Sets the search position in the RSA hardware.
    pub(super) fn write_search_position(&mut self, search_position: u32) {
        self.regs()
            .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 decrease security.
    ///
    /// For more information refer to 20.3.4 of <https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf>.
    pub fn enable_disable_constant_time_acceleration(&mut self, enable: bool) {
        self.regs()
            .constant_time()
            .write(|w| w.constant_time().bit(!enable));
    }

    /// Starts the modular exponentiation operation.
    pub(super) fn write_modexp_start(&self) {
        self.regs()
            .modexp_start()
            .write(|w| w.modexp_start().set_bit());
    }

    /// Starts the multiplication operation.
    pub(super) fn write_multi_start(&self) {
        self.regs().mult_start().write(|w| w.mult_start().set_bit());
    }

    /// Starts the modular multiplication operation.
    pub(super) fn write_modmulti_start(&self) {
        self.regs()
            .modmult_start()
            .write(|w| w.modmult_start().set_bit());
    }

    /// Clears the RSA interrupt flag.
    pub(super) fn clear_interrupt(&mut self) {
        self.regs().int_clr().write(|w| w.int_clr().set_bit());
    }

    /// Checks if the RSA peripheral is idle.
    pub(super) fn is_idle(&self) -> bool {
        self.regs().idle().read().idle().bit_is_set()
    }
}

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<'d, T: RsaMode, Dm: crate::DriverMode, const N: usize> RsaModularExponentiation<'_, 'd, T, Dm>
where
    T: RsaMode<InputType = [u32; N]>,
{
    pub(super) 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
    }

    /// Sets the modular exponentiation mode for the RSA hardware.
    pub(super) fn write_mode(rsa: &mut Rsa<'d, Dm>) {
        rsa.write_mode((N - 1) as u32)
    }
}

impl<'d, T: RsaMode, Dm: crate::DriverMode, const N: usize> RsaModularMultiplication<'_, 'd, T, Dm>
where
    T: RsaMode<InputType = [u32; N]>,
{
    pub(super) fn write_mode(rsa: &mut Rsa<'d, Dm>) {
        rsa.write_mode((N - 1) as u32)
    }

    pub(super) fn set_up_modular_multiplication(&mut self, operand_b: &T::InputType) {
        self.rsa.write_operand_b(operand_b);
    }
}

impl<'d, T: RsaMode + Multi, Dm: crate::DriverMode, const N: usize> RsaMultiplication<'_, 'd, T, Dm>
where
    T: RsaMode<InputType = [u32; N]>,
{
    /// Sets the multiplication mode for the RSA hardware.
    pub(super) fn write_mode(rsa: &mut Rsa<'d, Dm>) {
        rsa.write_mode((N * 2 - 1) as u32)
    }

    pub(super) fn set_up_multiplication(&mut self, operand_b: &T::InputType) {
        self.rsa.write_multi_operand_b(operand_b);
    }
}