Initial code.

src/lib/scryptenc/scryptenc.h

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