82e7917294
* Added authors and licenses and plugin access to crypto related files * removed `rz_hash` and related files * introduced `rz_msg_digest_*` with plugins * updated all old methods with newer ones. * added HMAC support to `rz-hash` (moved key option under `-K`) * removed wrong algorithms on `woD`/`woE` * fixed parity digest size * fixed the behaviour on all hash functions * added unit test for hash * optimized code for HMAC key calculation * removed hash legacy tests
40 lines
971 B
C
40 lines
971 B
C
// SPDX-FileCopyrightText: 2021 deroad <wargio@libero.it>
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// SPDX-License-Identifier: LGPL-3.0-only
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#include "entropy.h"
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#include <stdlib.h>
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#include <math.h>
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#include <rz_util/rz_assert.h>
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bool rz_entropy_init(RzEntropy *ctx) {
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rz_return_val_if_fail(ctx, false);
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memset(ctx, 0, sizeof(RzEntropy));
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return true;
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}
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bool rz_entropy_update(RzEntropy *ctx, const ut8 *data, size_t len) {
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rz_return_val_if_fail(ctx && data, false);
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for (size_t i = 0; i < len; i++) {
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ctx->count[data[i]]++;
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}
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ctx->size += len;
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return true;
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}
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bool rz_entropy_final(ut8 *digest, RzEntropy *ctx, bool fraction) {
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rz_return_val_if_fail(ctx && digest, false);
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double p, entropy = 0.0;
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ut64 count;
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for (size_t i = 0; i < 256; i++) {
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count = ctx->count[i];
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if (count) {
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p = ((double)count) / ctx->size;
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entropy -= p * log2(p);
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}
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}
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if (fraction && ctx->size) {
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entropy /= log2((double)RZ_MIN(ctx->size, 256));
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}
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rz_write_be_double(digest, entropy);
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return true;
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}
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