NAME<\/a> scrypt \u2212 EVP_PKEY scrypt KDF support<\/p>\n The EVP_PKEY_SCRYPT<\/small> algorithm implements the scrypt password based key derivation function, as described in RFC 7914.<\/small> It is memory-hard in the sense that it deliberately requires a significant amount of RAM<\/small> for efficient computation. The intention of this is to render brute forcing of passwords on systems that lack large amounts of main memory (such as GPUs or ASICs) computationally infeasible.<\/p>\n scrypt provides three work factors that can be customized: N, r and p. N, which has to be a positive power of two, is the general work factor and scales CPU<\/small> time in an approximately linear fashion. r is the block size of the internally used hash function and p is the parallelization factor. Both r and p need to be greater than zero. The amount of RAM<\/small> that scrypt requires for its computation is roughly (128 bodies manpages.csv script_extrae_body.sh script.sh usr N bodies manpages.csv script_extrae_body.sh script.sh usr r bodies manpages.csv script_extrae_body.sh script.sh usr p) bytes.<\/p>\n In the original paper of Colin Percival (“Stronger Key Derivation via Sequential Memory-Hard Functions”, 2009), the suggested values that give a computation time of less than 5 seconds on a 2.5 GHz Intel Core 2 Duo are N = 2^20 = 1048576, r = 8, p = 1. Consequently, the required amount of memory for this computation is roughly 1 GiB. On a more recent CPU<\/small> (Intel i7\u22125930K at 3.5 GHz), this computation takes about 3 seconds. When N, r or p are not specified, they default to 1048576, 8, and 1, respectively. The default amount of RAM<\/small> that may be used by scrypt defaults to 1025 MiB.<\/p>\n A context for scrypt can be obtained by calling:<\/p>\n EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_SCRYPT, NULL);<\/p>\n The output length of an scrypt key derivation is specified via the length parameter to the EVP_PKEY_derive<\/b>(3) function.<\/p>\n This example derives a 64\u2212byte long test vector using scrypt using the password “password”, salt “NaCl” and N = 1024, r = 8, p = 16.<\/p>\n EVP_PKEY_CTX *pctx; RFC 7914<\/small><\/p>\n EVP_PKEY_CTX_set1_scrypt_salt<\/b>(3), EVP_PKEY_CTX_set_scrypt_N<\/b>(3), EVP_PKEY_CTX_set_scrypt_r<\/b>(3), EVP_PKEY_CTX_set_scrypt_p<\/b>(3), EVP_PKEY_CTX_set_scrypt_maxmem_bytes<\/b>(3), EVP_PKEY_CTX_new<\/b>(3), EVP_PKEY_CTX_ctrl_str<\/b>(3), EVP_PKEY_derive<\/b>(3)<\/p>\n Copyright 2017\u22122019 The OpenSSL Project Authors. All Rights Reserved.<\/p>\n Licensed under the OpenSSL license (the “License”). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE<\/small> in the source distribution or at scrypt \u2212 EVP_PKEY scrypt KDF support <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[971],"tags":[973,972,1087],"class_list":["post-3999","post","type-post","status-publish","format-standard","hentry","category-7-miscelanea","tag-973","tag-man7","tag-scrypt"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3999","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=3999"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3999\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=3999"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=3999"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=3999"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
DESCRIPTION<\/a>
NOTES<\/a>
EXAMPLES<\/a>
CONFORMING TO<\/a>
SEE ALSO<\/a>
COPYRIGHT<\/a> <\/p>\n
\nNAME <\/a> <\/h2>\n
DESCRIPTION <\/a> <\/h2>\n
NOTES <\/a> <\/h2>\n
EXAMPLES <\/a> <\/h2>\n
unsigned char out[64];
size_t outlen = sizeof(out);
pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_SCRYPT, NULL);
if (EVP_PKEY_derive_init(pctx) <= 0) {
error(“EVP_PKEY_derive_init”);
}
if (EVP_PKEY_CTX_set1_pbe_pass(pctx, “password”, 8) <= 0) {
error(“EVP_PKEY_CTX_set1_pbe_pass”);
}
if (EVP_PKEY_CTX_set1_scrypt_salt(pctx, “NaCl”, 4) <= 0) {
error(“EVP_PKEY_CTX_set1_scrypt_salt”);
}
if (EVP_PKEY_CTX_set_scrypt_N(pctx, 1024) <= 0) {
error(“EVP_PKEY_CTX_set_scrypt_N”);
}
if (EVP_PKEY_CTX_set_scrypt_r(pctx, 8) <= 0) {
error(“EVP_PKEY_CTX_set_scrypt_r”);
}
if (EVP_PKEY_CTX_set_scrypt_p(pctx, 16) <= 0) {
error(“EVP_PKEY_CTX_set_scrypt_p”);
}
if (EVP_PKEY_derive(pctx, out, &outlen) <= 0) {
error(“EVP_PKEY_derive”);
}
{
const unsigned char expected[sizeof(out)] = {
0xfd, 0xba, 0xbe, 0x1c, 0x9d, 0x34, 0x72, 0x00,
0x78, 0x56, 0xe7, 0x19, 0x0d, 0x01, 0xe9, 0xfe,
0x7c, 0x6a, 0xd7, 0xcb, 0xc8, 0x23, 0x78, 0x30,
0xe7, 0x73, 0x76, 0x63, 0x4b, 0x37, 0x31, 0x62,
0x2e, 0xaf, 0x30, 0xd9, 0x2e, 0x22, 0xa3, 0x88,
0x6f, 0xf1, 0x09, 0x27, 0x9d, 0x98, 0x30, 0xda,
0xc7, 0x27, 0xaf, 0xb9, 0x4a, 0x83, 0xee, 0x6d,
0x83, 0x60, 0xcb, 0xdf, 0xa2, 0xcc, 0x06, 0x40
};
assert(!memcmp(out, expected, sizeof(out)));
}
EVP_PKEY_CTX_free(pctx);<\/p>\nCONFORMING TO <\/a> <\/h2>\n
SEE ALSO <\/a> <\/h2>\n
COPYRIGHT <\/a> <\/h2>\n
\n","protected":false},"excerpt":{"rendered":"