EVP_KEM-RSA(7)

EVP_KEM-RSA(7) | OpenSSL | EVP_KEM-RSA(7)

# NAME

EVP_KEM-RSA - EVP_KEM RSA keytype and algorithm support

# DESCRIPTION

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

## RSA KEM parameters

"operation" (OSSL_KEM_PARAM_OPERATION) <UTF8 string>
  The OpenSSL RSA Key Encapsulation Mechanism only currently supports the following default operation (operating mode):

"RSASVE"
  The encapsulate function simply generates a secret using random bytes and then encrypts the secret using the RSA public key (with no padding). The decapsulate function recovers the secret using the RSA private key.

This can be set using EVP_PKEY_CTX_set_kem_op().

"fips-indicator" (OSSL_KEM_PARAM_FIPS_APPROVED_INDICATOR) <integer>
"key-check" (OSSL_KEM_PARAM_FIPS_KEY_CHECK) <integer>
  These parameters are described in provider-kem(7).

# CONFORMING TO

SP800-56Br2
  Section 7.2.1.2 RSASVE Generate Operation (RSASVE.GENERATE). Section 7.2.1.3 RSASVE Recovery Operation (RSASVE.RECOVER).

# 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 3.0.

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

# COPYRIGHT

Copyright 2020-2025 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>.

2026-04-07 | 3.5.6