xref: /freebsd/secure/lib/libcrypto/man/man3/PKCS5_PBKDF2_HMAC.3 (revision 6be3386466ab79a84b48429ae66244f21526d3df)
Automatically generated by Pod::Man 4.14 (Pod::Simple 3.42)

Standard preamble:
========================================================================
..
..
.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "PKCS5_PBKDF2_HMAC 3"
PKCS5_PBKDF2_HMAC 3 "2021-02-16" "1.1.1j" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
PKCS5_PBKDF2_HMAC, PKCS5_PBKDF2_HMAC_SHA1 - password based derivation routines with salt and iteration count
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/evp.h> \& int PKCS5_PBKDF2_HMAC(const char *pass, int passlen, const unsigned char *salt, int saltlen, int iter, const EVP_MD *digest, int keylen, unsigned char *out); \& int PKCS5_PBKDF2_HMAC_SHA1(const char *pass, int passlen, const unsigned char *salt, int saltlen, int iter, int keylen, unsigned char *out); .Ve
"DESCRIPTION"
Header "DESCRIPTION" \s-1PKCS5_PBKDF2_HMAC\s0() derives a key from a password using a salt and iteration count as specified in \s-1RFC 2898.\s0

\fBpass is the password used in the derivation of length passlen. pass is an optional parameter and can be \s-1NULL.\s0 If passlen is -1, then the function will calculate the length of pass using strlen().

\fBsalt is the salt used in the derivation of length saltlen. If the \fBsalt is \s-1NULL,\s0 then saltlen must be 0. The function will not attempt to calculate the length of the salt because it is not assumed to be \s-1NULL\s0 terminated.

\fBiter is the iteration count and its value should be greater than or equal to 1. \s-1RFC 2898\s0 suggests an iteration count of at least 1000. Any \fBiter less than 1 is treated as a single iteration.

\fBdigest is the message digest function used in the derivation. Values include any of the EVP_* message digests. \s-1PKCS5_PBKDF2_HMAC_SHA1\s0() calls \s-1PKCS5_PBKDF2_HMAC\s0() with EVP_sha1().

The derived key will be written to out. The size of the out buffer is specified via keylen.

"NOTES"
Header "NOTES" A typical application of this function is to derive keying material for an encryption algorithm from a password in the pass, a salt in salt, and an iteration count.

Increasing the iter parameter slows down the algorithm which makes it harder for an attacker to perform a brute force attack using a large number of candidate passwords.

These functions make no assumption regarding the given password. It will simply be treated as a byte sequence.

"RETURN VALUES"
Header "RETURN VALUES" \s-1PKCS5_PBKDF2_HMAC\s0() and \s-1PBKCS5_PBKDF2_HMAC_SHA1\s0() return 1 on success or 0 on error.
"SEE ALSO"
Header "SEE ALSO" \fBevp\|(7), RAND_bytes\|(3), \fBEVP_BytesToKey\|(3), \fBpassphrase-encoding\|(7)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.