EVP_KEM-EC - EVP_KEM EC keytype and algorithm support
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.
- "operation" (OSSL_KEM_PARAM_OPERATION)<UTF8
string>
- The OpenSSL EC Key Encapsulation Mechanisms only supports the following
operation:
- "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.
EVP_PKEY_CTX_set_kem_op(3), EVP_PKEY_encapsulate(3),
EVP_PKEY_decapsulate(3) EVP_KEYMGMT(3), EVP_PKEY(3),
provider-keymgmt(7)
This functionality was added in OpenSSL 3.2.
Copyright 2022 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>.