121 lines
4.9 KiB
C
121 lines
4.9 KiB
C
/*-
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* Copyright 2009 Colin Percival
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file was originally written by Colin Percival as part of the Tarsnap
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* online backup system.
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*/
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#ifndef _SCRYPTENC_H_
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#define _SCRYPTENC_H_
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#include <stdint.h>
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#include <stdio.h>
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/**
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* NOTE: This file provides prototypes for routines which encrypt/decrypt data
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* using a key derived from a password by using the scrypt key derivation
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* function. If you are just trying to "hash" a password for user logins,
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* this is not the code you are looking for. You want to use the crypt_scrypt
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* function directly.
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*/
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/**
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* The parameters maxmem, maxmemfrac, and maxtime used by all of these
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* functions are defined as follows:
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* maxmem - maximum number of bytes of storage to use for V array (which is
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* by far the largest consumer of memory). If this value is set to 0, no
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* maximum will be enforced; any other value less than 1 MiB will be
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* treated as 1 MiB.
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* maxmemfrac - maximum fraction of available storage to use for the V array,
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* where "available storage" is defined as the minimum out of the
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* RLIMIT_AS, RLIMIT_DATA. and RLIMIT_RSS resource limits (if any are
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* set). If this value is set to 0 or more than 0.5 it will be treated
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* as 0.5; and this value will never cause a limit of less than 1 MiB to
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* be enforced.
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* maxtime - maximum amount of CPU time to spend computing the derived keys,
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* in seconds. This limit is only approximately enforced; the CPU
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* performance is estimated and parameter limits are chosen accordingly.
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* For the encryption functions, the parameters to the scrypt key derivation
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* function are chosen to make the key as strong as possible subject to the
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* specified limits; for the decryption functions, the parameters used are
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* compared to the computed limits and an error is returned if decrypting
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* the data would take too much memory or CPU time.
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*/
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/**
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* Return codes from scrypt(enc|dec)_(buf|file):
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* 0 success
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* 1 getrlimit or sysctl(hw.usermem) failed
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* 2 clock_getres or clock_gettime failed
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* 3 error computing derived key
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* 4 could not read salt from /dev/urandom
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* 5 error in OpenSSL
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* 6 malloc failed
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* 7 data is not a valid scrypt-encrypted block
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* 8 unrecognized scrypt format
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* 9 decrypting file would take too much memory
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* 10 decrypting file would take too long
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* 11 password is incorrect
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* 12 error writing output file
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* 13 error reading input file
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*/
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/**
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* scryptenc_buf(inbuf, inbuflen, outbuf, passwd, passwdlen,
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* maxmem, maxmemfrac, maxtime):
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* Encrypt inbuflen bytes from inbuf, writing the resulting inbuflen + 128
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* bytes to outbuf.
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*/
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int scryptenc_buf(const uint8_t *, size_t, uint8_t *,
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const uint8_t *, size_t, size_t, double, double);
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/**
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* scryptdec_buf(inbuf, inbuflen, outbuf, outlen, passwd, passwdlen,
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* maxmem, maxmemfrac, maxtime):
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* Decrypt inbuflen bytes from inbuf, writing the result into outbuf and the
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* decrypted data length to outlen. The allocated length of outbuf must
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* be at least inbuflen.
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*/
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int scryptdec_buf(const uint8_t *, size_t, uint8_t *, size_t *,
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const uint8_t *, size_t, size_t, double, double);
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/**
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* scryptenc_file(infile, outfile, passwd, passwdlen,
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* maxmem, maxmemfrac, maxtime):
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* Read a stream from infile and encrypt it, writing the resulting stream to
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* outfile.
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*/
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int scryptenc_file(FILE *, FILE *, const uint8_t *, size_t,
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size_t, double, double);
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/**
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* scryptdec_file(infile, outfile, passwd, passwdlen,
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* maxmem, maxmemfrac, maxtime):
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* Read a stream from infile and decrypt it, writing the resulting stream to
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* outfile.
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*/
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int scryptdec_file(FILE *, FILE *, const uint8_t *, size_t,
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size_t, double, double);
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#endif /* !_SCRYPTENC_H_ */
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