.\" $NetBSD: provider-digest.7,v 1.3 2023/10/25 17:17:57 christos Exp $ .\" .\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .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. \*(C+ will .\" give a nicer C++. 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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" provider\-digest \- The digest library <\-> provider functions .SH "LIBRARY" libcrypto, -lcrypto .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 2 \& #include \& #include \& \& /* \& * Digests support the following function signatures in OSSL_DISPATCH arrays. \& * (The function signatures are not actual functions). \& */ \& \& /* Context management */ \& void *OSSL_FUNC_digest_newctx(void *provctx); \& void OSSL_FUNC_digest_freectx(void *dctx); \& void *OSSL_FUNC_digest_dupctx(void *dctx); \& \& /* Digest generation */ \& int OSSL_FUNC_digest_init(void *dctx, const OSSL_PARAM params[]); \& int OSSL_FUNC_digest_update(void *dctx, const unsigned char *in, size_t inl); \& int OSSL_FUNC_digest_final(void *dctx, unsigned char *out, size_t *outl, \& size_t outsz); \& int OSSL_FUNC_digest_digest(void *provctx, const unsigned char *in, size_t inl, \& unsigned char *out, size_t *outl, size_t outsz); \& \& /* Digest parameter descriptors */ \& const OSSL_PARAM *OSSL_FUNC_digest_gettable_params(void *provctx); \& \& /* Digest operation parameter descriptors */ \& const OSSL_PARAM *OSSL_FUNC_digest_gettable_ctx_params(void *dctx, \& void *provctx); \& const OSSL_PARAM *OSSL_FUNC_digest_settable_ctx_params(void *dctx, \& void *provctx); \& \& /* Digest parameters */ \& int OSSL_FUNC_digest_get_params(OSSL_PARAM params[]); \& \& /* Digest operation parameters */ \& int OSSL_FUNC_digest_set_ctx_params(void *dctx, const OSSL_PARAM params[]); \& int OSSL_FUNC_digest_get_ctx_params(void *dctx, OSSL_PARAM params[]); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" This documentation is primarily aimed at provider authors. See \fBprovider\fR\|(7) for further information. .PP The \s-1DIGEST\s0 operation enables providers to implement digest algorithms and make them available to applications via the \s-1API\s0 functions \fBEVP_DigestInit_ex\fR\|(3), \&\fBEVP_DigestUpdate\fR\|(3) and \fBEVP_DigestFinal\fR\|(3) (and other related functions). .PP All \*(L"functions\*(R" mentioned here are passed as function pointers between \&\fIlibcrypto\fR and the provider in \s-1\fBOSSL_DISPATCH\s0\fR\|(3) arrays via \&\s-1\fBOSSL_ALGORITHM\s0\fR\|(3) arrays that are returned by the provider's \&\fBprovider_query_operation()\fR function (see \*(L"Provider Functions\*(R" in \fBprovider\-base\fR\|(7)). .PP All these \*(L"functions\*(R" have a corresponding function type definition named \fBOSSL_FUNC_{name}_fn\fR, and a helper function to retrieve the function pointer from an \s-1\fBOSSL_DISPATCH\s0\fR\|(3) element named \&\fBOSSL_FUNC_{name}\fR. For example, the \*(L"function\*(R" \fBOSSL_FUNC_digest_newctx()\fR has these: .PP .Vb 3 \& typedef void *(OSSL_FUNC_digest_newctx_fn)(void *provctx); \& static ossl_inline OSSL_FUNC_digest_newctx_fn \& OSSL_FUNC_digest_newctx(const OSSL_DISPATCH *opf); .Ve .PP \&\s-1\fBOSSL_DISPATCH\s0\fR\|(3) arrays are indexed by numbers that are provided as macros in \fBopenssl\-core_dispatch.h\fR\|(7), as follows: .PP .Vb 3 \& OSSL_FUNC_digest_newctx OSSL_FUNC_DIGEST_NEWCTX \& OSSL_FUNC_digest_freectx OSSL_FUNC_DIGEST_FREECTX \& OSSL_FUNC_digest_dupctx OSSL_FUNC_DIGEST_DUPCTX \& \& OSSL_FUNC_digest_init OSSL_FUNC_DIGEST_INIT \& OSSL_FUNC_digest_update OSSL_FUNC_DIGEST_UPDATE \& OSSL_FUNC_digest_final OSSL_FUNC_DIGEST_FINAL \& OSSL_FUNC_digest_digest OSSL_FUNC_DIGEST_DIGEST \& \& OSSL_FUNC_digest_get_params OSSL_FUNC_DIGEST_GET_PARAMS \& OSSL_FUNC_digest_get_ctx_params OSSL_FUNC_DIGEST_GET_CTX_PARAMS \& OSSL_FUNC_digest_set_ctx_params OSSL_FUNC_DIGEST_SET_CTX_PARAMS \& \& OSSL_FUNC_digest_gettable_params OSSL_FUNC_DIGEST_GETTABLE_PARAMS \& OSSL_FUNC_digest_gettable_ctx_params OSSL_FUNC_DIGEST_GETTABLE_CTX_PARAMS \& OSSL_FUNC_digest_settable_ctx_params OSSL_FUNC_DIGEST_SETTABLE_CTX_PARAMS .Ve .PP A digest algorithm implementation may not implement all of these functions. In order to be usable all or none of OSSL_FUNC_digest_newctx, OSSL_FUNC_digest_freectx, OSSL_FUNC_digest_init, OSSL_FUNC_digest_update and OSSL_FUNC_digest_final should be implemented. All other functions are optional. .SS "Context Management Functions" .IX Subsection "Context Management Functions" \&\fBOSSL_FUNC_digest_newctx()\fR should create and return a pointer to a provider side structure for holding context information during a digest operation. A pointer to this context will be passed back in a number of the other digest operation function calls. The parameter \fIprovctx\fR is the provider context generated during provider initialisation (see \fBprovider\fR\|(7)). .PP \&\fBOSSL_FUNC_digest_freectx()\fR is passed a pointer to the provider side digest context in the \fIdctx\fR parameter. This function should free any resources associated with that context. .PP \&\fBOSSL_FUNC_digest_dupctx()\fR should duplicate the provider side digest context in the \&\fIdctx\fR parameter and return the duplicate copy. .SS "Digest Generation Functions" .IX Subsection "Digest Generation Functions" \&\fBOSSL_FUNC_digest_init()\fR initialises a digest operation given a newly created provider side digest context in the \fIdctx\fR parameter. The \fIparams\fR, if not \s-1NULL,\s0 should be set on the context in a manner similar to using \fBOSSL_FUNC_digest_set_ctx_params()\fR. .PP \&\fBOSSL_FUNC_digest_update()\fR is called to supply data to be digested as part of a previously initialised digest operation. The \fIdctx\fR parameter contains a pointer to a previously initialised provider side context. \&\fBOSSL_FUNC_digest_update()\fR should digest \fIinl\fR bytes of data at the location pointed to by \fIin\fR. \&\fBOSSL_FUNC_digest_update()\fR may be called multiple times for a single digest operation. .PP \&\fBOSSL_FUNC_digest_final()\fR generates a digest started through previous \fBOSSL_FUNC_digest_init()\fR and \fBOSSL_FUNC_digest_update()\fR calls. The \fIdctx\fR parameter contains a pointer to the provider side context. The digest should be written to \fI*out\fR and the length of the digest to \&\fI*outl\fR. The digest should not exceed \fIoutsz\fR bytes. .PP \&\fBOSSL_FUNC_digest_digest()\fR is a \*(L"oneshot\*(R" digest function. No provider side digest context is used. Instead the provider context that was created during provider initialisation is passed in the \fIprovctx\fR parameter (see \fBprovider\fR\|(7)). \&\fIinl\fR bytes at \fIin\fR should be digested and the result should be stored at \&\fIout\fR. The length of the digest should be stored in \fI*outl\fR which should not exceed \fIoutsz\fR bytes. .SS "Digest Parameters" .IX Subsection "Digest Parameters" See \s-1\fBOSSL_PARAM\s0\fR\|(3) for further details on the parameters structure used by these functions. .PP \&\fBOSSL_FUNC_digest_get_params()\fR gets details of the algorithm implementation and stores them in \fIparams\fR. .PP \&\fBOSSL_FUNC_digest_set_ctx_params()\fR sets digest operation parameters for the provider side digest context \fIdctx\fR to \fIparams\fR. Any parameter settings are additional to any that were previously set. Passing \s-1NULL\s0 for \fIparams\fR should return true. .PP \&\fBOSSL_FUNC_digest_get_ctx_params()\fR gets digest operation details details from the given provider side digest context \fIdctx\fR and stores them in \fIparams\fR. Passing \s-1NULL\s0 for \fIparams\fR should return true. .PP \&\fBOSSL_FUNC_digest_gettable_params()\fR returns a constant \s-1\fBOSSL_PARAM\s0\fR\|(3) array containing descriptors of the parameters that \fBOSSL_FUNC_digest_get_params()\fR can handle. .PP \&\fBOSSL_FUNC_digest_gettable_ctx_params()\fR and \&\fBOSSL_FUNC_digest_settable_ctx_params()\fR both return constant \&\s-1\fBOSSL_PARAM\s0\fR\|(3) arrays as descriptors of the parameters that \&\fBOSSL_FUNC_digest_get_ctx_params()\fR and \fBOSSL_FUNC_digest_set_ctx_params()\fR can handle, respectively. The array is based on the current state of the provider side context if \fIdctx\fR is not \s-1NULL\s0 and on the provider side algorithm \fIprovctx\fR otherwise. .PP Parameters currently recognised by built-in digests with this function are as follows. Not all parameters are relevant to, or are understood by all digests: .ie n .IP """blocksize"" (\fB\s-1OSSL_DIGEST_PARAM_BLOCK_SIZE\s0\fR) " 4 .el .IP "``blocksize'' (\fB\s-1OSSL_DIGEST_PARAM_BLOCK_SIZE\s0\fR) " 4 .IX Item "blocksize (OSSL_DIGEST_PARAM_BLOCK_SIZE) " The digest block size. The length of the \*(L"blocksize\*(R" parameter should not exceed that of a \fBsize_t\fR. .ie n .IP """size"" (\fB\s-1OSSL_DIGEST_PARAM_SIZE\s0\fR) " 4 .el .IP "``size'' (\fB\s-1OSSL_DIGEST_PARAM_SIZE\s0\fR) " 4 .IX Item "size (OSSL_DIGEST_PARAM_SIZE) " The digest output size. The length of the \*(L"size\*(R" parameter should not exceed that of a \fBsize_t\fR. .ie n .IP """flags"" (\fB\s-1OSSL_DIGEST_PARAM_FLAGS\s0\fR) " 4 .el .IP "``flags'' (\fB\s-1OSSL_DIGEST_PARAM_FLAGS\s0\fR) " 4 .IX Item "flags (OSSL_DIGEST_PARAM_FLAGS) " Diverse flags that describe exceptional behaviour for the digest: .RS 4 .IP "\fB\s-1EVP_MD_FLAG_ONESHOT\s0\fR" 4 .IX Item "EVP_MD_FLAG_ONESHOT" This digest method can only handle one block of input. .IP "\fB\s-1EVP_MD_FLAG_XOF\s0\fR" 4 .IX Item "EVP_MD_FLAG_XOF" This digest method is an extensible-output function (\s-1XOF\s0) and supports setting the \fB\s-1OSSL_DIGEST_PARAM_XOFLEN\s0\fR parameter. .IP "\fB\s-1EVP_MD_FLAG_DIGALGID_NULL\s0\fR" 4 .IX Item "EVP_MD_FLAG_DIGALGID_NULL" When setting up a DigestAlgorithmIdentifier, this flag will have the parameter set to \s-1NULL\s0 by default. Use this for PKCS#1. \fINote: if combined with \s-1EVP_MD_FLAG_DIGALGID_ABSENT,\s0 the latter will override.\fR .IP "\fB\s-1EVP_MD_FLAG_DIGALGID_ABSENT\s0\fR" 4 .IX Item "EVP_MD_FLAG_DIGALGID_ABSENT" When setting up a DigestAlgorithmIdentifier, this flag will have the parameter be left absent by default. \fINote: if combined with \&\s-1EVP_MD_FLAG_DIGALGID_NULL,\s0 the latter will be overridden.\fR .IP "\fB\s-1EVP_MD_FLAG_DIGALGID_CUSTOM\s0\fR" 4 .IX Item "EVP_MD_FLAG_DIGALGID_CUSTOM" Custom DigestAlgorithmIdentifier handling via ctrl, with \&\fB\s-1EVP_MD_FLAG_DIGALGID_ABSENT\s0\fR as default. \fINote: if combined with \&\s-1EVP_MD_FLAG_DIGALGID_NULL,\s0 the latter will be overridden.\fR Currently unused. .RE .RS 4 .Sp The length of the \*(L"flags\*(R" parameter should equal that of an \&\fBunsigned long int\fR. .RE .SS "Digest Context Parameters" .IX Subsection "Digest Context Parameters" \&\fBOSSL_FUNC_digest_set_ctx_params()\fR sets digest parameters associated with the given provider side digest context \fIdctx\fR to \fIparams\fR. Any parameter settings are additional to any that were previously set. See \s-1\fBOSSL_PARAM\s0\fR\|(3) for further details on the parameters structure. .PP \&\fBOSSL_FUNC_digest_get_ctx_params()\fR gets details of currently set parameters values associated with the give provider side digest context \fIdctx\fR and stores them in \fIparams\fR. See \s-1\fBOSSL_PARAM\s0\fR\|(3) for further details on the parameters structure. .SH "RETURN VALUES" .IX Header "RETURN VALUES" \&\fBOSSL_FUNC_digest_newctx()\fR and \fBOSSL_FUNC_digest_dupctx()\fR should return the newly created provider side digest context, or \s-1NULL\s0 on failure. .PP \&\fBOSSL_FUNC_digest_init()\fR, \fBOSSL_FUNC_digest_update()\fR, \fBOSSL_FUNC_digest_final()\fR, \fBOSSL_FUNC_digest_digest()\fR, \&\fBOSSL_FUNC_digest_set_params()\fR and \fBOSSL_FUNC_digest_get_params()\fR should return 1 for success or 0 on error. .PP \&\fBOSSL_FUNC_digest_size()\fR should return the digest size. .PP \&\fBOSSL_FUNC_digest_block_size()\fR should return the block size of the underlying digest algorithm. .SH "BUGS" .IX Header "BUGS" The \fBEVP_Q_digest()\fR, \fBEVP_Digest()\fR and \fBEVP_DigestFinal_ex()\fR \s-1API\s0 calls do not expect the digest size to be larger than \s-1EVP_MAX_MD_SIZE.\s0 Any algorithm which produces larger digests is unusable with those \s-1API\s0 calls. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBprovider\fR\|(7), \s-1\fBOSSL_PROVIDER\-FIPS\s0\fR\|(7), \fBOSSL_PROVIDER\-default\fR\|(7), \&\fBOSSL_PROVIDER\-legacy\fR\|(7), \&\fBEVP_MD\-common\fR\|(7), \s-1\fBEVP_MD\-BLAKE2\s0\fR\|(7), \s-1\fBEVP_MD\-MD2\s0\fR\|(7), \&\s-1\fBEVP_MD\-MD4\s0\fR\|(7), \s-1\fBEVP_MD\-MD5\s0\fR\|(7), \s-1\fBEVP_MD\-MD5\-SHA1\s0\fR\|(7), \&\s-1\fBEVP_MD\-MDC2\s0\fR\|(7), \s-1\fBEVP_MD\-RIPEMD160\s0\fR\|(7), \s-1\fBEVP_MD\-SHA1\s0\fR\|(7), \&\s-1\fBEVP_MD\-SHA2\s0\fR\|(7), \s-1\fBEVP_MD\-SHA3\s0\fR\|(7), \s-1\fBEVP_MD\-SHAKE\s0\fR\|(7), \&\s-1\fBEVP_MD\-SM3\s0\fR\|(7), \s-1\fBEVP_MD\-WHIRLPOOL\s0\fR\|(7), \&\s-1\fBEVP_MD\-NULL\s0\fR\|(7), \&\fBlife_cycle\-digest\fR\|(7), \fBEVP_DigestInit\fR\|(3) .SH "HISTORY" .IX Header "HISTORY" The provider \s-1DIGEST\s0 interface was introduced in OpenSSL 3.0. .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 2019\-2023 The OpenSSL Project Authors. All Rights Reserved. .PP 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 .