Provided by: openssl_3.5.3-1ubuntu3.3_amd64 bug

NAME
       EVP_KEM-EC - EVP_KEM EC keytype and algorithm support


DESCRIPTION
       The EC keytype and its parameters are described in EVP_PKEY-EC(7).  See EVP_PKEY_encapsulate(3) and
       EVP_PKEY_decapsulate(3) for more info.

   EC KEM parameters
       "operation" (OSSL_KEM_PARAM_OPERATION)<UTF8 string>
           The  OpenSSL EC Key Encapsulation Mechanisms only supports the following default operation (operating
           mode):

           "DHKEM" (OSSL_KEM_PARAM_OPERATION_DHKEM)
               The encapsulate function generates an ephemeral keypair. It produces keymaterial by doing an ECDH
               key exchange using the ephemeral private  key  and  a  supplied  recipient  public  key.  A  HKDF
               operation  using  the  keymaterial  and  a  kem context then produces a shared secret. The shared
               secret and the ephemeral public key are returned.  The decapsulate function  uses  the  recipient
               private  key and the ephemeral public key to produce the same keymaterial, which can then be used
               to          produce          the           same           shared           secret.            See
               <https://www.rfc-editor.org/rfc/rfc9180.html#name-dh-based-kem-dhkem>

           This can be set using either EVP_PKEY_CTX_set_kem_op() or EVP_PKEY_CTX_set_params().

       "ikme" (OSSL_KEM_PARAM_IKME) <octet string>
           Used  to specify the key material used for generation of the ephemeral key.  This value should not be
           reused for other purposes.  It can only be used for the  curves  "P-256",  "P-384"  and  "P-521"  and
           should  have  a  length  of  at least the size of the encoded private key (i.e. 32, 48 and 66 for the
           listed curves).  If this value is not set, then a random ikm is used.


CONFORMING TO
       RFC9180


SEE ALSO
       EVP_PKEY_CTX_set_kem_op(3), EVP_PKEY_encapsulate(3), EVP_PKEY_decapsulate(3) EVP_KEYMGMT(3), EVP_PKEY(3),
       provider-keymgmt(7)


HISTORY
       This functionality was added in OpenSSL 3.2.

       The "operation" (operating mode) was a required parameter prior to  OpenSSL  3.5.   As  of  OpenSSL  3.5,
       "DHKEM" is the default operating mode, and no explicit value need be specified.


COPYRIGHT
       Copyright 2022-2025 The OpenSSL Project Authors. All Rights Reserved.

       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>.

3.5.3                                              2025-09-16                                   EVP_KEM-EC(7SSL)