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Diffstat (limited to 'secure/lib/libcrypto/man/EVP_BytesToKey.3')
-rw-r--r-- | secure/lib/libcrypto/man/EVP_BytesToKey.3 | 204 |
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diff --git a/secure/lib/libcrypto/man/EVP_BytesToKey.3 b/secure/lib/libcrypto/man/EVP_BytesToKey.3 new file mode 100644 index 0000000..46fa6e7 --- /dev/null +++ b/secure/lib/libcrypto/man/EVP_BytesToKey.3 @@ -0,0 +1,204 @@ +.\" Automatically generated by Pod::Man version 1.15 +.\" Mon Jan 13 19:28:01 2003 +.\" +.\" Standard preamble: +.\" ====================================================================== +.de Sh \" Subsection heading +.br +.if t .Sp +.ne 5 +.PP +\fB\\$1\fR +.PP +.. +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Ip \" List item +.br +.ie \\n(.$>=3 .ne \\$3 +.el .ne 3 +.IP "\\$1" \\$2 +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R + +.fi +.. +.\" 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. | will give a +.\" real vertical bar. \*(C+ will give a nicer C++. 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The derived key and \s-1IV\s0 will be written to \fBkey\fR +and \fBiv\fR respectively. +.SH "NOTES" +.IX Header "NOTES" +A typical application of this function is to derive keying material for an +encryption algorithm from a password in the \fBdata\fR parameter. +.PP +Increasing the \fBcount\fR parameter slows down the algorithm which makes it +harder for an attacker to peform a brute force attack using a large number +of candidate passwords. +.PP +If the total key and \s-1IV\s0 length is less than the digest length and +\&\fB\s-1MD5\s0\fR is used then the derivation algorithm is compatible with PKCS#5 v1.5 +otherwise a non standard extension is used to derive the extra data. +.PP +Newer applications should use more standard algorithms such as PKCS#5 +v2.0 for key derivation. +.SH "KEY DERIVATION ALGORITHM" +.IX Header "KEY DERIVATION ALGORITHM" +The key and \s-1IV\s0 is derived by concatenating D_1, D_2, etc until +enough data is available for the key and \s-1IV\s0. D_i is defined as: +.PP +.Vb 1 +\& D_i = HASH^count(D_(i-1) || data || salt) +.Ve +where || denotes concatentaion, D_0 is empty, \s-1HASH\s0 is the digest +algorithm in use, HASH^1(data) is simply HASH(data), HASH^2(data) +is HASH(HASH(data)) and so on. +.PP +The initial bytes are used for the key and the subsequent bytes for +the \s-1IV\s0. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +\&\fIEVP_BytesToKey()\fR returns the size of the derived key in bytes. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +evp(3), rand(3), +EVP_EncryptInit(3), +.SH "HISTORY" +.IX Header "HISTORY" |