2 * Copyright 2009 Colin Percival
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * This file was originally written by Colin Percival as part of the Tarsnap
27 * online backup system.
36 * The parameters maxmem, maxmemfrac, and maxtime used by all of these
37 * functions are defined as follows:
38 * maxmem - maximum number of bytes of storage to use for V array (which is
39 * by far the largest consumer of memory). If this value is set to 0, no
40 * maximum will be enforced; any other value less than 1 MiB will be
42 * maxmemfrac - maximum fraction of available storage to use for the V array,
43 * where "available storage" is defined as the minimum out of the
44 * RLIMIT_AS, RLIMIT_DATA. and RLIMIT_RSS resource limits (if any are
45 * set). If this value is set to 0 or more than 0.5 it will be treated
46 * as 0.5; and this value will never cause a limit of less than 1 MiB to
48 * maxtime - maximum amount of CPU time to spend computing the derived keys,
49 * in seconds. This limit is only approximately enforced; the CPU
50 * performance is estimated and parameter limits are chosen accordingly.
51 * For the encryption functions, the parameters to the scrypt key derivation
52 * function are chosen to make the key as strong as possible subject to the
53 * specified limits; for the decryption functions, the parameters used are
54 * compared to the computed limits and an error is returned if decrypting
55 * the data would take too much memory or CPU time.
58 * Return codes from scrypt(enc|dec)_(buf|file):
60 * 1 getrlimit or sysctl(hw.usermem) failed
61 * 2 clock_getres or clock_gettime failed
62 * 3 error computing derived key
63 * 4 could not read salt from /dev/urandom
66 * 7 data is not a valid scrypt-encrypted block
67 * 8 unrecognized scrypt format
68 * 9 decrypting file would take too much memory
69 * 10 decrypting file would take too long
70 * 11 password is incorrect
71 * 12 error writing output file
72 * 13 error reading input file
76 * scryptenc_buf(inbuf, inbuflen, outbuf, passwd, passwdlen,
77 * maxmem, maxmemfrac, maxtime):
78 * Encrypt inbuflen bytes from inbuf, writing the resulting inbuflen + 128
81 int scryptenc_buf(const uint8_t *, size_t, uint8_t *,
82 const uint8_t *, size_t, size_t, double, double);
85 * scryptdec_buf(inbuf, inbuflen, outbuf, outlen, passwd, passwdlen,
86 * maxmem, maxmemfrac, maxtime):
87 * Decrypt inbuflen bytes from inbuf, writing the result into outbuf and the
88 * decrypted data length to outlen. The allocated length of outbuf must
89 * be at least inbuflen.
91 int scryptdec_buf(const uint8_t *, size_t, uint8_t *, size_t *,
92 const uint8_t *, size_t, size_t, double, double);
95 * scryptenc_file(infile, outfile, passwd, passwdlen,
96 * maxmem, maxmemfrac, maxtime):
97 * Read a stream from infile and encrypt it, writing the resulting stream to
100 int scryptenc_file(FILE *, FILE *, const uint8_t *, size_t,
101 size_t, double, double);
104 * scryptdec_file(infile, outfile, passwd, passwdlen,
105 * maxmem, maxmemfrac, maxtime):
106 * Read a stream from infile and decrypt it, writing the resulting stream to
109 int scryptdec_file(FILE *, FILE *, const uint8_t *, size_t,
110 size_t, double, double);
112 #endif /* !_SCRYPTENC_H_ */