xref: /freebsd/secure/lib/libcrypto/man/man7/EVP_RAND-SEED-SRC.7 (revision a4e5e0106ac7145f56eb39a691e302cabb4635be)
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 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 "EVP_RAND-SEED-SRC 7ossl"
EVP_RAND-SEED-SRC 7ossl "2023-09-19" "3.0.11" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
EVP_RAND-SEED-SRC - The randomness seed source EVP_RAND implementation
"DESCRIPTION"
Header "DESCRIPTION" Support for deterministic random number generator seeding through the \fB\s-1EVP_RAND\s0 \s-1API.\s0

The seed sources used are specified at the time OpenSSL is configured for building using the --with-rand-seed= option. By default, operating system randomness sources are used.

"Identity"
Subsection "Identity" \*(L"SEED-SRC\*(R" is the name for this implementation; it can be used with the \fBEVP_RAND_fetch() function.
"Supported parameters"
Subsection "Supported parameters" The supported parameters are: Item "state (OSSL_RAND_PARAM_STATE) <integer>"

0 Item "strength (OSSL_RAND_PARAM_STRENGTH) <unsigned integer>" Item "max_request (OSSL_RAND_PARAM_MAX_REQUEST) <unsigned integer>"

These parameters work as described in \*(L"\s-1PARAMETERS\*(R"\s0 in \s-1EVP_RAND\s0\|(3).

"NOTES"
Header "NOTES" A context for the seed source can be obtained by calling:

.Vb 2 EVP_RAND *rand = EVP_RAND_fetch(NULL, "SEED-SRC", NULL); EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand); .Ve

"EXAMPLES"
Header "EXAMPLES" .Vb 5 EVP_RAND *rand; EVP_RAND_CTX *seed, *rctx; unsigned char bytes[100]; OSSL_PARAM params[2], *p = params; unsigned int strength = 128; \& /* Create a seed source */ rand = EVP_RAND_fetch(NULL, "SEED-SRC", NULL); seed = EVP_RAND_CTX_new(rand, NULL); EVP_RAND_free(rand); \& /* Feed this into a DRBG */ rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL); rctx = EVP_RAND_CTX_new(rand, seed); EVP_RAND_free(rand); \& /* Configure the DRBG */ *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER, SN_aes_256_ctr, 0); *p = OSSL_PARAM_construct_end(); EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params); \& EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0); \& EVP_RAND_CTX_free(rctx); EVP_RAND_CTX_free(seed); .Ve
"SEE ALSO"
Header "SEE ALSO" \s-1EVP_RAND\s0\|(3), \*(L"\s-1PARAMETERS\*(R"\s0 in \s-1EVP_RAND\s0\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (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>.