1 .\" $OpenBSD: PKCS5_PBKDF2_HMAC.3,v 1.6 2018/03/23 04:34:23 schwarze Exp $
2 .\" OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
4 .\" This file was written by Jeffrey Walton <noloader@gmail.com>.
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51 .Dd $Mdocdate: March 23 2018 $
52 .Dt PKCS5_PBKDF2_HMAC 3
55 .Nm PKCS5_PBKDF2_HMAC ,
56 .Nm PKCS5_PBKDF2_HMAC_SHA1
57 .Nd password based derivation routines with salt and iteration count
62 .Fa "const char *pass"
64 .Fa "const unsigned char *salt"
67 .Fa "const EVP_MD *digest"
69 .Fa "unsigned char *out"
72 .Fo PKCS5_PBKDF2_HMAC_SHA1
73 .Fa "const char *pass"
75 .Fa "const unsigned char *salt"
79 .Fa "unsigned char *out"
83 derives a key from a password using a salt and iteration count as
84 specified in RFC 2898.
87 is the password used in the derivation of length
90 is an optional parameter and can be
94 is -1, then the function will calculate the length of
100 is the salt used in the derivation of length
109 The function will not attempt to calculate the length of the
111 because it is not assumed to be NUL terminated.
114 is the iteration count and its value should be greater than or equal to 1.
115 RFC 2898 suggests an iteration count of at least 1000.
118 less than 1 is treated as a single iteration.
121 is the message digest function used in the derivation.
122 Values include any of the EVP_* message digests.
123 .Fn PKCS5_PBKDF2_HMAC_SHA1
125 .Fn PKCS5_PBKDF2_HMAC
129 The derived key will be written to
133 buffer is specified via
136 A typical application of this function is to derive keying material for
137 an encryption algorithm from a password in the
141 and an iteration count.
145 parameter slows down the algorithm which makes it harder for an attacker
146 to perform a brute force attack using a large number of candidate
149 .Fn PKCS5_PBKDF2_HMAC
151 .Fn PBKCS5_PBKDF2_HMAC_SHA1
152 return 1 on success or 0 on error.
155 .Xr EVP_BytesToKey 3 ,
158 .Fn PKCS5_PBKDF2_HMAC_SHA1
159 first appeared in OpenSSL 0.9.4 and has been available since
162 .Fn PKCS5_PBKDF2_HMAC
163 first appeared in OpenSSL 1.0.0 and has been available since