42 lines
1.4 KiB
C
42 lines
1.4 KiB
C
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// Important: The SoftDevice *must* be activated to enable reading from the RNG
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// http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Frng.html
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#include <nrf_soc.h>
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static int
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hydro_random_init(void)
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{
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const char ctx[hydro_hash_CONTEXTBYTES] = { 'h', 'y', 'd', 'r', 'o', 'P', 'R', 'G' };
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hydro_hash_state st;
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const uint8_t total_bytes = 32;
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uint8_t remaining_bytes = total_bytes;
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uint8_t available_bytes;
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uint8_t rand_buffer[32];
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hydro_hash_init(&st, ctx, NULL);
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for (;;) {
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if (sd_rand_application_bytes_available_get(&available_bytes) != NRF_SUCCESS) {
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return -1;
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}
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if (available_bytes > 0) {
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if (available_bytes > remaining_bytes) {
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available_bytes = remaining_bytes;
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}
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if (sd_rand_application_vector_get(rand_buffer, available_bytes) != NRF_SUCCESS) {
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return -1;
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}
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hydro_hash_update(&st, rand_buffer, total_bytes);
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remaining_bytes -= available_bytes;
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}
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if (remaining_bytes <= 0) {
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break;
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}
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delay(10);
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}
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hydro_hash_final(&st, hydro_random_context.state, sizeof hydro_random_context.state);
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hydro_random_context.counter = ~LOAD64_LE(hydro_random_context.state);
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return 0;
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}
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