153 lines
3.4 KiB
C
153 lines
3.4 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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/**
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@file sprng.c
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Secure PRNG, Tom St Denis
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*/
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/* A secure PRNG using the RNG functions. Basically this is a
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* wrapper that allows you to use a secure RNG as a PRNG
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* in the various other functions.
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*/
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#ifdef LTC_SPRNG
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const struct ltc_prng_descriptor sprng_desc =
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{
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"sprng", 0,
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&sprng_start,
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&sprng_add_entropy,
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&sprng_ready,
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&sprng_read,
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&sprng_done,
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&sprng_export,
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&sprng_import,
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&sprng_test
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};
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/**
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Start the PRNG
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@param prng [out] The PRNG state to initialize
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@return CRYPT_OK if successful
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*/
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int sprng_start(prng_state *prng)
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{
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LTC_UNUSED_PARAM(prng);
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return CRYPT_OK;
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}
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/**
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Add entropy to the PRNG state
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@param in The data to add
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@param inlen Length of the data to add
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@param prng PRNG state to update
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@return CRYPT_OK if successful
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*/
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int sprng_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng)
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{
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LTC_UNUSED_PARAM(in);
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LTC_UNUSED_PARAM(inlen);
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LTC_UNUSED_PARAM(prng);
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return CRYPT_OK;
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}
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/**
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Make the PRNG ready to read from
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@param prng The PRNG to make active
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@return CRYPT_OK if successful
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*/
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int sprng_ready(prng_state *prng)
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{
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LTC_UNUSED_PARAM(prng);
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return CRYPT_OK;
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}
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/**
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Read from the PRNG
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@param out Destination
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@param outlen Length of output
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@param prng The active PRNG to read from
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@return Number of octets read
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*/
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unsigned long sprng_read(unsigned char *out, unsigned long outlen, prng_state *prng)
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{
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LTC_ARGCHK(out != NULL);
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LTC_UNUSED_PARAM(prng);
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return rng_get_bytes(out, outlen, NULL);
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}
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/**
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Terminate the PRNG
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@param prng The PRNG to terminate
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@return CRYPT_OK if successful
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*/
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int sprng_done(prng_state *prng)
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{
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LTC_UNUSED_PARAM(prng);
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return CRYPT_OK;
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}
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/**
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Export the PRNG state
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@param out [out] Destination
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@param outlen [in/out] Max size and resulting size of the state
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@param prng The PRNG to export
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@return CRYPT_OK if successful
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*/
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/* NOLINTNEXTLINE(readability-non-const-parameter) - silence clang-tidy warning */
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int sprng_export(unsigned char *out, unsigned long *outlen, prng_state *prng)
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{
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LTC_ARGCHK(outlen != NULL);
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LTC_UNUSED_PARAM(out);
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LTC_UNUSED_PARAM(prng);
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*outlen = 0;
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return CRYPT_OK;
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}
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/**
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Import a PRNG state
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@param in The PRNG state
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@param inlen Size of the state
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@param prng The PRNG to import
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@return CRYPT_OK if successful
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*/
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int sprng_import(const unsigned char *in, unsigned long inlen, prng_state *prng)
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{
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LTC_UNUSED_PARAM(in);
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LTC_UNUSED_PARAM(inlen);
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LTC_UNUSED_PARAM(prng);
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return CRYPT_OK;
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}
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/**
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PRNG self-test
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@return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled
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*/
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int sprng_test(void)
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{
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#ifndef LTC_TEST
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return CRYPT_NOP;
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#else
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prng_state st;
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unsigned char en[] = { 0x01, 0x02, 0x03, 0x04 };
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unsigned char out[1000];
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int err;
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if ((err = sprng_start(&st)) != CRYPT_OK) return err;
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if ((err = sprng_add_entropy(en, sizeof(en), &st)) != CRYPT_OK) return err;
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if ((err = sprng_ready(&st)) != CRYPT_OK) return err;
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if (sprng_read(out, 500, &st) != 500) return CRYPT_ERROR_READPRNG; /* skip 500 bytes */
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if ((err = sprng_done(&st)) != CRYPT_OK) return err;
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return CRYPT_OK;
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#endif
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}
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#endif
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