b570175b47
a PRNG that is no PRNG as its output is predefined and can be set by calling add_entropy()
149 lines
3.0 KiB
C
149 lines
3.0 KiB
C
/* LibTomCrypt, modular cryptographic library
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* http://libtom.org
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*/
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#include "tomcrypt.h"
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/**
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@file no_prng.c
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NO PRNG, Steffen Jaeckel
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*/
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#ifdef LTC_PKCS_1
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static unsigned char no_prng_entropy[1024];
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static unsigned long no_prng_len = 0;
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static unsigned long no_prng_offset = 0;
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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 no_prng_start(prng_state *prng)
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{
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no_prng_len = 0;
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no_prng_offset = 0;
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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 no_prng_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng)
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{
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LTC_ARGCHK(in != NULL);
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LTC_ARGCHK(inlen <= sizeof(no_prng_entropy));
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no_prng_len = MIN(inlen, sizeof(no_prng_entropy));
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memcpy(no_prng_entropy, in, no_prng_len);
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no_prng_offset = 0;
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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 no_prng_ready(prng_state *prng)
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{
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LTC_ARGCHK(prng != NULL);
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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 no_prng_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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outlen = MIN(outlen, no_prng_len - no_prng_offset);
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memcpy(out, &no_prng_entropy[no_prng_offset], outlen);
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no_prng_offset += outlen;
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return outlen;
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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 no_prng_done(prng_state *prng)
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{
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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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int no_prng_export(unsigned char *out, unsigned long *outlen, prng_state *prng)
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{
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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 no_prng_import(const unsigned char *in, unsigned long inlen, prng_state *prng)
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{
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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 no_prng_test(void)
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{
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return CRYPT_OK;
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}
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const struct ltc_prng_descriptor no_prng_desc =
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{
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"no_prng", 0,
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&no_prng_start,
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&no_prng_add_entropy,
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&no_prng_ready,
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&no_prng_read,
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&no_prng_done,
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&no_prng_export,
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&no_prng_import,
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&no_prng_test
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};
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#endif
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/* $Source$ */
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/* $Revision$ */
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/* $Date$ */
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