[openssl/openssl] 78c44b: Add HPKE DHKEM provider support for EC, X25519 and...

Shane noreply at github.com
Fri Sep 23 08:27:39 UTC 2022

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 78c44b05945be07eae86f0164b9b777e2de2295b
  Author: slontis <shane.lontis at oracle.com>
  Date:   2022-09-23 (Fri, 23 Sep 2022)

  Changed paths:
    M crypto/build.info
    M crypto/ec/build.info
    M crypto/ec/ec_key.c
    M crypto/ec/ecx_key.c
    M crypto/evp/evp_local.h
    M crypto/evp/kem.c
    A crypto/hpke/build.info
    A crypto/hpke/hpke_util.c
    M doc/build.info
    M doc/man3/EVP_PKEY_decapsulate.pod
    M doc/man3/EVP_PKEY_encapsulate.pod
    A doc/man7/EVP_KEM-EC.pod
    A doc/man7/EVP_KEM-X25519.pod
    M doc/man7/EVP_PKEY-EC.pod
    M doc/man7/EVP_PKEY-X25519.pod
    M doc/man7/OSSL_PROVIDER-default.pod
    M doc/man7/provider-kem.pod
    M include/crypto/ec.h
    M include/crypto/ecx.h
    A include/crypto/hpke.h
    M include/openssl/core_dispatch.h
    M include/openssl/core_names.h
    M include/openssl/evp.h
    M providers/defltprov.c
    M providers/implementations/exchange/ecx_exch.c
    A providers/implementations/include/prov/ecx.h
    M providers/implementations/include/prov/implementations.h
    M providers/implementations/kem/build.info
    A providers/implementations/kem/ec_kem.c
    A providers/implementations/kem/eckem.h
    A providers/implementations/kem/ecx_kem.c
    A providers/implementations/kem/kem_util.c
    M providers/implementations/keymgmt/ec_kmgmt.c
    M providers/implementations/keymgmt/ecx_kmgmt.c
    M test/build.info
    A test/dhkem_test.inc
    A test/evp_pkey_dhkem_test.c
    A test/recipes/30-test_evp_pkey_dhkem.t
    M util/libcrypto.num

  Log Message:
  Add HPKE DHKEM provider support for EC, X25519 and X448.

The code is derived from @sftcd's work in PR #17172.
This PR puts the DHKEM algorithms into the provider layer as
KEM algorithms for EC and ECX.

This PR only implements the DHKEM component of HPKE as specified in
RFC 9180.

crypto/hpke/hpke_util.c has been added for fuctions that will
be shared between DHKEM and HPKE.

API's for EVP_PKEY_auth_encapsulate_init() and EVP_PKEY_auth_decapsulate_init()
have been added to support authenticated encapsulation. auth_init() functions
were chosen rather that a EVP_PKEY_KEM_set_auth() interface to support
future algorithms that could possibly need different init functions.

Internal code has been refactored, so that it can be shared between the DHKEM
and other systems. Since DHKEM operates on low level keys it needs to be
able to do low level ECDH and ECXDH calls without converting the keys
back into EVP_PKEY/EVP_PKEY_CTX form. See ossl_ecx_compute_key(),

DHKEM requires API's to derive a key using a seed (IKM). This did not sit
well inside the DHKEM itself as dispatch functions. This functionality
fits better inside the EC and ECX keymanagers keygen, since
they are just variations of keygen where the private key is generated
in a different manner. This should mainly be used for testing purposes.
See ossl_ec_generate_key_dhkem().
It supports this by allowing a settable param to be passed to keygen
The keygen calls code within ec and ecx dhkem implementation to handle this.
See ossl_ecx_dhkem_derive_private() and ossl_ec_dhkem_derive_private().
These 2 functions are also used by the EC/ECX DHKEM implementations to generate
the sender ephemeral keys.

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Matt Caswell <matt at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19068)

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