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Diffstat (limited to 'secure/lib/libcrypto/man/man3/EVP_PKEY_decapsulate.3')
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diff --git a/secure/lib/libcrypto/man/man3/EVP_PKEY_decapsulate.3 b/secure/lib/libcrypto/man/man3/EVP_PKEY_decapsulate.3 new file mode 100644 index 000000000000..872bead492a1 --- /dev/null +++ b/secure/lib/libcrypto/man/man3/EVP_PKEY_decapsulate.3 @@ -0,0 +1,191 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man v6.0.2 (Pod::Simple 3.45) +.\" +.\" 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 +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'br\} +.\" +.\" Escape single quotes in literal strings from groff's Unicode transform. +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" +.\" 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'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" +.\" Required to disable full justification in groff 1.23.0. +.if n .ds AD l +.\" ======================================================================== +.\" +.IX Title "EVP_PKEY_DECAPSULATE 3ossl" +.TH EVP_PKEY_DECAPSULATE 3ossl 2026-04-07 3.5.6 OpenSSL +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH NAME +EVP_PKEY_decapsulate_init, EVP_PKEY_auth_decapsulate_init, EVP_PKEY_decapsulate +\&\- Key decapsulation using a KEM algorithm with a private key +.SH SYNOPSIS +.IX Header "SYNOPSIS" +.Vb 1 +\& #include <openssl/evp.h> +\& +\& int EVP_PKEY_decapsulate_init(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[]); +\& int EVP_PKEY_auth_decapsulate_init(EVP_PKEY_CTX *ctx, EVP_PKEY *authpub, +\& const OSSL_PARAM params[]); +\& int EVP_PKEY_decapsulate(EVP_PKEY_CTX *ctx, +\& unsigned char *unwrapped, size_t *unwrappedlen, +\& const unsigned char *wrapped, size_t wrappedlen); +.Ve +.SH DESCRIPTION +.IX Header "DESCRIPTION" +The \fBEVP_PKEY_decapsulate_init()\fR function initializes a private key algorithm +context \fIctx\fR for a decapsulation operation and then sets the \fIparams\fR +on the context in the same way as calling \fBEVP_PKEY_CTX_set_params\fR\|(3). +Note that \fIctx\fR usually is produced using \fBEVP_PKEY_CTX_new_from_pkey\fR\|(3), +specifying the private key to use. +.PP +The \fBEVP_PKEY_auth_decapsulate_init()\fR function is similar to +\&\fBEVP_PKEY_decapsulate_init()\fR but also passes an \fIauthpub\fR authentication public +key that is used during decapsulation. +.PP +The \fBEVP_PKEY_decapsulate()\fR function performs a private key decapsulation +operation using \fIctx\fR. The data to be decapsulated is specified using the +\&\fIwrapped\fR and \fIwrappedlen\fR parameters (which must both non\-NULL). +.PP +The \fIwrapped\fR parameter is an output argument, to which the decapsulated +shared secret is written. +The shared secret may not match the peer\*(Aqs value even when decapsulation +returns success. +Instead, the shared secret must be used to derive a key that is used to +authenticate data subsequently received from the peer. +If \fIunwrapped\fR is NULL then the size of the output shared secret buffer is +written to \fI*unwrappedlen\fR and no decapsulation is performed, this makes it +possible to determine the required buffer size at run time. Otherwise, the +decapsulated secret data is written to \fIunwrapped\fR and the length of shared +secret is written to \fI*unwrappedlen\fR. +.PP +Note that the value pointed to by \fIunwrappedlen\fR (which must NOT be \fBNULL\fR) +must be initialised to the length of \fIunwrapped\fR, so that the call can +validate it is of sufficient size to hold the result of the operation. +.PP +Absent detailed prior knowledge of the internals of the specific KEM +algorithm, callers SHOULD NOT assume that the returned shared secret +is necessarily of the maximum possible length. +The length returned via \fI*unwrappedlen\fR SHOULD be used to determine the actual +length of the output. +.SH NOTES +.IX Header "NOTES" +After the call to \fBEVP_PKEY_decapsulate_init()\fR algorithm\-specific parameters +for the operation may be set or modified using \fBEVP_PKEY_CTX_set_params\fR\|(3). +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +\&\fBEVP_PKEY_decapsulate_init()\fR, \fBEVP_PKEY_auth_decapsulate_init()\fR and +\&\fBEVP_PKEY_decapsulate()\fR return 1 for success and 0 or a negative value for +failure. In particular a return value of \-2 indicates the operation is not +supported by the private key algorithm. +.SH EXAMPLES +.IX Header "EXAMPLES" +Decapsulate data using RSA: +.PP +.Vb 1 +\& #include <openssl/evp.h> +\& +\& /* +\& * NB: assumes rsa_priv_key is an RSA private key, +\& * and that in, inlen are already set up to contain encapsulated data. +\& */ +\& +\& EVP_PKEY_CTX *ctx = NULL; +\& size_t secretlen = 0; +\& unsigned char *secret = NULL;; +\& +\& ctx = EVP_PKEY_CTX_new_from_pkey(libctx, rsa_priv_key, NULL); +\& if (ctx == NULL) +\& /* Error */ +\& if (EVP_PKEY_decapsulate_init(ctx, NULL) <= 0) +\& /* Error */ +\& +\& /* Set the mode \- only \*(AqRSASVE\*(Aq is currently supported */ +\& if (EVP_PKEY_CTX_set_kem_op(ctx, "RSASVE") <= 0) +\& /* Error */ +\& +\& /* Determine buffer length */ +\& if (EVP_PKEY_decapsulate(ctx, NULL, &secretlen, in, inlen) <= 0) +\& /* Error */ +\& +\& secret = OPENSSL_malloc(secretlen); +\& if (secret == NULL) +\& /* malloc failure */ +\& +\& /* Decapsulated secret data is secretlen bytes long */ +\& if (EVP_PKEY_decapsulate(ctx, secret, &secretlen, in, inlen) <= 0) +\& /* Error */ +.Ve +.SH "SEE ALSO" +.IX Header "SEE ALSO" +\&\fBEVP_PKEY_CTX_new_from_pkey\fR\|(3), +\&\fBEVP_PKEY_encapsulate\fR\|(3), +\&\fBEVP_KEM\-RSA\fR\|(7), +\&\fBEVP_KEM\-X25519\fR\|(7), +\&\fBEVP_KEM\-EC\fR\|(7), +\&\fBEVP_KEM\-ML\-KEM\-512\fR\|(7), +\&\fBEVP_KEM\-ML\-KEM\-768\fR\|(7), +\&\fBEVP_KEM\-ML\-KEM\-1024\fR\|(7) +.SH HISTORY +.IX Header "HISTORY" +The functions \fBEVP_PKEY_decapsulate_init()\fR and \fBEVP_PKEY_decapsulate()\fR were added +in OpenSSL 3.0. +.PP +The function \fBEVP_PKEY_auth_decapsulate_init()\fR was added in OpenSSL 3.2. +.PP +Support for \fBML\-KEM\fR was added in OpenSSL 3.5. +.SH COPYRIGHT +.IX Header "COPYRIGHT" +Copyright 2020\-2025 The OpenSSL Project Authors. All Rights Reserved. +.PP +Licensed under the Apache License 2.0 (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>. |