HMAC - Online Linux Manual PageSection : 3
Updated : 2021-03-26
Source : 1.1.1k
Note : OpenSSL

NAMEHMAC, HMAC_CTX_new, HMAC_CTX_reset, HMAC_CTX_free, HMAC_Init, HMAC_Init_ex, HMAC_Update, HMAC_Final, HMAC_CTX_copy, HMAC_CTX_set_flags, HMAC_CTX_get_md, HMAC_size ​− HMAC message authentication code

SYNOPSIS​ #include <openssl/hmac.h> ​ ​ unsigned char *HMAC(const EVP_MD *evp_md, const void *key, ​ int key_len, const unsigned char *d, size_t n, ​ unsigned char *md, unsigned int *md_len); ​ ​ HMAC_CTX *HMAC_CTX_new(void); ​ int HMAC_CTX_reset(HMAC_CTX *ctx); ​ ​ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int key_len, ​ const EVP_MD *md, ENGINE *impl); ​ int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len); ​ int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len); ​ ​ void HMAC_CTX_free(HMAC_CTX *ctx); ​ ​ int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx); ​ void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags); ​ const EVP_MD *HMAC_CTX_get_md(const HMAC_CTX *ctx); ​ ​ size_t HMAC_size(const HMAC_CTX *e); Deprecated: ​ #if OPENSSL_API_COMPAT < 0x10100000L ​ int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, ​ const EVP_MD *md); ​ #endif

DESCRIPTIONHMAC is a MAC (message authentication code), i.e. a keyed hash function used for message authentication, which is based on a hash function. HMAC() computes the message authentication code of the n bytes at ​d using the hash function evp_md and the key key which is ​key_len bytes long. It places the result in md (which must have space for the output of the hash function, which is no more than EVP_MAX_MD_SIZE bytes). If md is NULL, the digest is placed in a static array. The size of the output is placed in md_len, unless it is NULL. Note: passing a NULL value for md to use the static array is not thread safe. evp_md is a message digest such as EVP_sha1(), EVP_ripemd160() etc. HMAC does not support variable output length digests such as EVP_shake128() and ​EVP_shake256(). HMAC_CTX_new() creates a new HMAC_CTX in heap memory. HMAC_CTX_reset() zeros an existing HMAC_CTX and associated resources, making it suitable for new computations as if it was newly created with(). HMAC_CTX_free() erases the key and other data from the HMAC_CTX, releases any associated resources and finally frees the HMAC_CTX itself. The following functions may be used if the message is not completely stored in memory: HMAC_Init_ex() initializes or reuses a HMAC_CTX structure to use the hash function evp_md and key key. If both are NULL, or if key is NULL and evp_md is the same as the previous call, then the existing key is reused. ctx must have been created with HMAC_CTX_new() before the first use of an HMAC_CTX in this function. If HMAC_Init_ex() is called with key NULL and evp_md is not the same as the previous digest used by ctx then an error is returned because reuse of an existing key with a different digest is not supported. HMAC_Init() initializes a HMAC_CTX structure to use the hash function evp_md and the key key which is key_len bytes long. HMAC_Update() can be called repeatedly with chunks of the message to be authenticated (len bytes at data). HMAC_Final() places the message authentication code in md, which must have space for the hash function output. HMAC_CTX_copy() copies all of the internal state from sctx into dctx. HMAC_CTX_set_flags() applies the specified flags to the internal EVP_MD_CTXs. These flags have the same meaning as for EVP_MD_CTX_set_flags(3). HMAC_CTX_get_md() returns the EVP_MD that has previously been set for the supplied HMAC_CTX. HMAC_size() returns the length in bytes of the underlying hash function output.

RETURN VALUESHMAC() returns a pointer to the message authentication code or NULL if an error occurred. HMAC_CTX_new() returns a pointer to a new HMAC_CTX on success or ​NULL if an error occurred. HMAC_CTX_reset(), HMAC_Init_ex(), HMAC_Update(), HMAC_Final() and ​HMAC_CTX_copy() return 1 for success or 0 if an error occurred. HMAC_CTX_get_md() return the EVP_MD previously set for the supplied HMAC_CTX or ​NULL if no EVP_MD has been set. HMAC_size() returns the length in bytes of the underlying hash function output or zero on error.

CONFORMING TORFC 2104

SEE ALSOSHA1(3), evp(7)

HISTORYHMAC_CTX_init() was replaced with HMAC_CTX_reset() in OpenSSL 1.1.0. HMAC_CTX_cleanup() existed in OpenSSL before version 1.1.0. HMAC_CTX_new(), HMAC_CTX_free() and HMAC_CTX_get_md() are new in OpenSSL 1.1.0. HMAC_Init_ex(), HMAC_Update() and HMAC_Final() did not return values in OpenSSL before version 1.0.0.

COPYRIGHTCopyright 2000−2020 The OpenSSL Project Authors. All Rights Reserved. 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 in the source distribution or at <https://www.openssl.org/source/license.html>.
0
Johanes Gumabo
Data Size   :   21,363 byte
man-HMAC_CTX_set_flags.3sslBuild   :   2024-12-05, 20:55   :  
Visitor Screen   :   x
Visitor Counter ( page / site )   :   2 / 164,462
Visitor ID   :     :  
Visitor IP   :   3.144.98.43   :  
Visitor Provider   :   AMAZON-02   :  
Provider Position ( lat x lon )   :   39.962500 x -83.006100   :   x
Provider Accuracy Radius ( km )   :   1000   :  
Provider City   :   Columbus   :  
Provider Province   :   Ohio ,   :   ,
Provider Country   :   United States   :  
Provider Continent   :   North America   :  
Visitor Recorder   :   Version   :  
Visitor Recorder   :   Library   :  
Online Linux Manual Page   :   Version   :   Online Linux Manual Page - Fedora.40 - march=x86-64 - mtune=generic - 24.12.05
Online Linux Manual Page   :   Library   :   lib_c - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Online Linux Manual Page   :   Library   :   lib_m - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Data Base   :   Version   :   Online Linux Manual Page Database - 24.04.13 - march=x86-64 - mtune=generic - fedora-38
Data Base   :   Library   :   lib_c - 23.02.07 - march=x86-64 - mtune=generic - fedora.36

Very long time ago, I have the best tutor, Wenzel Svojanovsky . If someone knows the email address of Wenzel Svojanovsky , please send an email to johanes_gumabo@yahoo.co.id .
If error, please print screen and send to johanes_gumabo@yahoo.co.id
Under development. Support me via PayPal.

ERROR : Need New Coding :         (parse_manual_page_|249|H___MAC.3ssl|36/37|el══─{─══.|.el══─{─══. ds -- \|\(em\| )         (htmlprn|149|H___MAC.3ssl|36/37|.el══─{─══. ds --  —  |.el══─{─══. ds -- \|\(em\| )         (parse_manual_page_|249|H___MAC.3ssl|43|br══─}─══|'br══─}─══ )         (htmlprn|149|H___MAC.3ssl|43|'br══─}─══ |'br══─}─══ )