1 // SPDX-License-Identifier: GPL-2.0-only
4  * Currently uses SHA-256 to scramble the PRNG state.
13 /* Begin SHA-256 related definitions */
49 	return value >> count | value << (32 - count);  in rot()
72 enum alphabet { A, B, C, D, E, F, G, H, };  enumerator
82 		w[i] = lower_sig1(w[i - 2]) + w[i - 7] + lower_sig0(w[i - 15]) + w[i - 16];  in sha256_chunk()
90 		     upper_sig1(w_hash[E]) +  in sha256_chunk()
91 		     ch(w_hash[E], w_hash[F], w_hash[G]) +  in sha256_chunk()
99 		w_hash[F] = w_hash[E];  in sha256_chunk()
100 		w_hash[E] = w_hash[D] + t1;  in sha256_chunk()
112  * sha256_hash - Calculate SHA-256 of input. Only a limited subset of inputs supported.
118  * Calculate the SHA-256 hash of the input where the input must be a multiple of
123  * The function computes the same as: printf "%08x" ${input[@]} | xxd -r -p | sha256sum .
128 	 * Pad according to SHA-2 specification.  in sha256_hash()
142 /* End SHA-256 related definitions */
157 	memcpy(input, state->hash, sizeof(state->hash));  in prng_scramble()
158 	sha256_hash(ARRAY_SIZE(input), &input, &state->hash);  in prng_scramble()
159 	state->next_word = 0;  in prng_scramble()
164 	if (state->next_word < ARRAY_SIZE(state->hash))  in prng32()
165 		return state->hash[state->next_word++];  in prng32()