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<p class="MsoNormal"><span lang="EN-IN">to exactly replace this we are generating “<b><span style="background:yellow;mso-highlight:yellow">pubparam_key</span>/<span style="background:aqua;mso-highlight:aqua">priparam_key</span></b>” using bn_publicKey/dh->priv_key
as below<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">OSSL_PARAM_BLD *pubparamsbld = NULL, priparamsbld = NULL;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">OSSL_PARAM *pubparams = NULL, priparams = NULL;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">EVP_PKEY *pubparam_key = NULL, *priparam_key = NULL;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">EVP_PKEY_CTX *pubctx = NULL, *prictx = NULL;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">pubparamsbld = OSSL_PARAM_BLD_new()<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">priparamsbld = OSSL_PARAM_BLD_new()<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">OSSL_PARAM_BLD_push_BN(pubparamsbld, OSSL_PKEY_PARAM_PUB_KEY, bn_publicKey)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">OSSL_PARAM_BLD_push_BN(priparamsbld, OSSL_PKEY_PARAM_PRIV_KEY,bn_privateKey)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">//build context<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">pubctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">prictx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">EVP_PKEY_key_fromdata_init(pubctx)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">EVP_PKEY_key_fromdata_init(prictx)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">pubparams = OSSL_PARAM_BLD_to_param(pubparamsbld);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">EVP_PKEY_fromdata(pubctx, &<span style="background:yellow;mso-highlight:yellow">pubparam_key</span>, pubparams))<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">priparams = OSSL_PARAM_BLD_to_param(priparamsbld);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">EVP_PKEY_fromdata(prictx, &<span style="background:aqua;mso-highlight:aqua">priparam_key</span>, priparams))<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">From there, we are planning to use EVP_PKEY_derive_init, EVP_PKEY_derive_set_peer, and EVP_PKEY_derive to get shared secret
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">Didn’t you generate the private keys using the EVP_PKEY_gen as was suggested to your previous email inquiry? If so, you shouldn’t have to rebuild it in such a way, since you already have a usable PKEY that has the generated
keypair. If you created a private keypair called privkey, the public key data can be sent to your peer with i2d_PUBKEY_bio(peer_bio, privkey) and received on the peer’s side with d2i_PUBKEY_bio(peer_bio, &peerkey);<br>
<br>
Now you just need to build a new context around your private EVP_PKEY using derive_ctx = EVP_PKEY_CTX_new(privkey, NULL); and then do the EVP_PKEY_derive series of calls.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN">Your example code does not seem to set the P or G parameters of your keypair, so if you must do it that way, you will need to add them too.<o:p></o:p></span></p>
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