NAME<\/a> EVP_KDF_SSHKDF \u2212 The SSHKDF EVP_KDF implementation<\/p>\n Support for computing the SSHKDF<\/small><\/b> KDF<\/small> through the EVP_KDF<\/small><\/b> API.<\/small><\/p>\n The EVP_KDF_SSHKDF<\/small> algorithm implements the SSHKDF<\/small> key derivation function. It is defined in RFC 4253,<\/small> section 7.2 and is used by SSH<\/small> to derive IVs, encryption keys and integrity keys. Five inputs are required to perform key derivation: The hashing function (for example SHA256<\/small> ), the Initial Key, the Exchange Hash, the Session ID,<\/small> and the derivation key type.<\/p>\n Numeric identity Supported controls<\/b> These controls work as described in ” CONTROLS”<\/small> in EVP_KDF_CTX<\/small><\/b> (3).<\/p>\n EVP_KDF_CTRL_SET_SSHKDF_XCGHASH These controls expect two arguments: “unsigned char *buffer”, “size_t length”<\/p>\n They set the respective values to the first length<\/b> bytes of the buffer buffer<\/b>. If a value is already set, the contents are replaced.<\/p>\n EVP_KDF_ctrl_str()<\/b> takes two type strings for these controls: The value string is used as is.<\/p>\n “hexxcghash” The value string is expected to be a hexadecimal number, which will be decoded before being passed on as the control value.<\/p>\n EVP_KDF_CTRL_SET_SSHKDF_TYPE<\/small><\/b><\/p>\n This control expects one argument: “int mode”<\/p>\n Sets the type for the SSHHKDF<\/small> operation. There are six supported types: The Initial IV<\/small> from client to server. A single char of value 65 ( ASCII<\/small> char \u2019A\u2019).<\/p>\n EVP_KDF_SSHKDF_TYPE_ININITAL_IV_SRV_TO_CLI<\/small><\/p>\n The Initial IV<\/small> from server to client A single char of value 66 ( ASCII<\/small> char \u2019B\u2019).<\/p>\n EVP_KDF_SSHKDF_TYPE_ENCRYPTION_KEY_CLI_TO_SRV<\/small><\/p>\n The Encryption Key from client to server A single char of value 67 ( ASCII<\/small> char \u2019C\u2019).<\/p>\n EVP_KDF_SSHKDF_TYPE_ENCRYPTION_KEY_SRV_TO_CLI<\/small><\/p>\n The Encryption Key from server to client A single char of value 68 ( ASCII<\/small> char \u2019D\u2019).<\/p>\n EVP_KDF_SSHKDF_TYPE_INTEGRITY_KEY_CLI_TO_SRV<\/small><\/p>\n The Integrity Key from client to server A single char of value 69 ( ASCII<\/small> char \u2019E\u2019).<\/p>\n EVP_KDF_SSHKDF_TYPE_INTEGRITY_KEY_SRV_TO_CLI<\/small><\/p>\n The Integrity Key from client to server A single char of value 70 ( ASCII<\/small> char \u2019F\u2019).<\/p>\n EVP_KDF_ctrl_str()<\/b> type string: “type”<\/p>\n The value is a string of length one character. The only valid values are the numerical values of the ASCII<\/small> caracters: “A” (65) to “F” (70).<\/p>\n A context for SSHKDF<\/small> can be obtained by calling:<\/p>\n EVP_KDF_CTX *kctx = EVP_KDF_CTX_new_id(EVP_KDF_SSHKDF);<\/p>\n The output length of the SSHKDF<\/small> derivation is specified via the “keylen” parameter to the EVP_KDF_derive<\/b>(3) function. Since the SSHKDF<\/small> output length is variable, calling EVP_KDF_size()<\/b> to obtain the requisite length is not meaningful. The caller must allocate a buffer of the desired length, and pass that buffer to the EVP_KDF_derive<\/b>(3) function along with the desired length.<\/p>\n This example derives an 8 byte IV<\/small> using SHA\u2212256<\/small> with a 1K “key” and appropriate “xcghash” and “session_id” values:<\/p>\n EVP_KDF_CTX *kctx; RFC 4253<\/small><\/p>\n EVP_KDF_CTX<\/small> , EVP_KDF_CTX_new_id<\/b>(3), EVP_KDF_CTX_free<\/b>(3), EVP_KDF_ctrl<\/b>(3), EVP_KDF_size<\/b>(3), EVP_KDF_derive<\/b>(3), ” CONTROLS”<\/small> in EVP_KDF_CTX<\/small><\/b> (3)<\/p>\n Copyright 2016\u22122018 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 EVP_KDF_SSHKDF \u2212 The SSHKDF EVP_KDF implementation <\/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":[973,1074,972],"class_list":["post-3985","post","type-post","status-publish","format-standard","hentry","category-7-miscelanea","tag-973","tag-evp_kdf_sshkdf","tag-man7"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3985","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=3985"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3985\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=3985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=3985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=3985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
DESCRIPTION<\/a>
NOTES<\/a>
EXAMPLE<\/a>
CONFORMING TO<\/a>
SEE ALSO<\/a>
COPYRIGHT<\/a> <\/p>\n
\nNAME <\/a> <\/h2>\n
DESCRIPTION <\/a> <\/h2>\n
EVP_KDF_SSHKDF<\/small><\/b> is the numeric identity for this implementation; it can be used with the EVP_KDF_CTX_new_id()<\/b> function.<\/p>\n
The supported controls are:
EVP_KDF_CTRL_SET_MD
EVP_KDF_CTRL_SET_KEY<\/small><\/b><\/p>\n
EVP_KDF_CTRL_SET_SSHKDF_SESSION_ID<\/small><\/b><\/p>\n
“xcghash”
“session_id”<\/p>\n
“hexsession_id”<\/p>\n
EVP_KDF_SSHKDF_TYPE_ININITAL_IV_CLI_TO_SRV<\/small><\/p>\nNOTES <\/a> <\/h2>\n
EXAMPLE <\/a> <\/h2>\n
unsigned char key[1024] = “01234…”;
unsigned char xcghash[32] = “012345…”;
unsigned char session_id[32] = “012345…”;
unsigned char out[8];
size_t outlen = sizeof(out);
kctx = EVP_KDF_CTX_new_id(EVP_KDF_SSHKDF);
if (EVP_KDF_CTX_set_md(kctx, EVP_sha256()) <= 0)
\/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Error bodies\/ usr\/
if (EVP_KDF_CTX_set1_key(kctx, key, 1024) <= 0)
\/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Error bodies\/ usr\/
if (EVP_KDF_CTX_set1_sshkdf_xcghash(kctx, xcghash, 32) <= 0)
\/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Error bodies\/ usr\/
if (EVP_KDF_CTX_set1_sshkdf_session_id(kctx, session_id, 32) <= 0)
\/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Error bodies\/ usr\/
if (EVP_KDF_CTX_set_sshkdf_type(kctx,
EVP_KDF_SSHKDF_TYPE_ININITAL_IV_CLI_TO_SRV) <= 0)
\/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Error bodies\/ usr\/
if (EVP_KDF_derive(kctx, out, &outlen) <= 0)
\/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Error *\/<\/p>\nCONFORMING TO <\/a> <\/h2>\n
SEE ALSO <\/a> <\/h2>\n
COPYRIGHT <\/a> <\/h2>\n
\n","protected":false},"excerpt":{"rendered":"