- NAME
- SYNOPSIS
- DESCRIPTION
- WARNINGS
- NOTES
- RETURN VALUES
- SEE ALSO
- HISTORY
- COPYRIGHT

# NAME

EVP_PKEY_set1_RSA, EVP_PKEY_set1_DSA, EVP_PKEY_set1_DH, EVP_PKEY_set1_EC_KEY, EVP_PKEY_get1_RSA, EVP_PKEY_get1_DSA, EVP_PKEY_get1_DH, EVP_PKEY_get1_EC_KEY, EVP_PKEY_get0_RSA, EVP_PKEY_get0_DSA, EVP_PKEY_get0_DH, EVP_PKEY_get0_EC_KEY, EVP_PKEY_assign_RSA, EVP_PKEY_assign_DSA, EVP_PKEY_assign_DH, EVP_PKEY_assign_EC_KEY, EVP_PKEY_assign_POLY1305, EVP_PKEY_assign_SIPHASH, EVP_PKEY_get0_hmac, EVP_PKEY_get0_poly1305, EVP_PKEY_get0_siphash, EVP_PKEY_get0, EVP_PKEY_type, EVP_PKEY_get_id, EVP_PKEY_get_base_id, EVP_PKEY_set1_engine, EVP_PKEY_get0_engine, EVP_PKEY_id, EVP_PKEY_base_id - EVP_PKEY assignment functions

# SYNOPSIS

     #include <openssl/evp.h>

     int EVP_PKEY_get_id(const EVP_PKEY *pkey);
     int EVP_PKEY_get_base_id(const EVP_PKEY *pkey);
     int EVP_PKEY_type(int type);

     #define EVP_PKEY_id EVP_PKEY_get_id
     #define EVP_PKEY_base_id EVP_PKEY_get_base_id

The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):

     int EVP_PKEY_set1_RSA(EVP_PKEY *pkey, RSA *key);
     int EVP_PKEY_set1_DSA(EVP_PKEY *pkey, DSA *key);
     int EVP_PKEY_set1_DH(EVP_PKEY *pkey, DH *key);
     int EVP_PKEY_set1_EC_KEY(EVP_PKEY *pkey, EC_KEY *key);

     RSA *EVP_PKEY_get1_RSA(EVP_PKEY *pkey);
     DSA *EVP_PKEY_get1_DSA(EVP_PKEY *pkey);
     DH *EVP_PKEY_get1_DH(EVP_PKEY *pkey);
     EC_KEY *EVP_PKEY_get1_EC_KEY(EVP_PKEY *pkey);

     const unsigned char *EVP_PKEY_get0_hmac(const EVP_PKEY *pkey, size_t *len);
     const unsigned char *EVP_PKEY_get0_poly1305(const EVP_PKEY *pkey, size_t *len);
     const unsigned char *EVP_PKEY_get0_siphash(const EVP_PKEY *pkey, size_t *len);
     const RSA *EVP_PKEY_get0_RSA(const EVP_PKEY *pkey);
     const DSA *EVP_PKEY_get0_DSA(const EVP_PKEY *pkey);
     const DH *EVP_PKEY_get0_DH(const EVP_PKEY *pkey);
     const EC_KEY *EVP_PKEY_get0_EC_KEY(const EVP_PKEY *pkey);
     void *EVP_PKEY_get0(const EVP_PKEY *pkey);

     int EVP_PKEY_assign_RSA(EVP_PKEY *pkey, RSA *key);
     int EVP_PKEY_assign_DSA(EVP_PKEY *pkey, DSA *key);
     int EVP_PKEY_assign_DH(EVP_PKEY *pkey, DH *key);
     int EVP_PKEY_assign_EC_KEY(EVP_PKEY *pkey, EC_KEY *key);
     int EVP_PKEY_assign_POLY1305(EVP_PKEY *pkey, ASN1_OCTET_STRING *key);
     int EVP_PKEY_assign_SIPHASH(EVP_PKEY *pkey, ASN1_OCTET_STRING *key);

     ENGINE *EVP_PKEY_get0_engine(const EVP_PKEY *pkey);
     int EVP_PKEY_set1_engine(EVP_PKEY *pkey, ENGINE *engine);

# DESCRIPTION

`EVP_PKEY_get_base_id()` returns the type of pkey. For example an RSA key will return EVP_PKEY_RSA.

`EVP_PKEY_get_id()` returns the actual NID associated with pkey only if the pkey type isn't implemented just in a provider(7). Historically keys using the same algorithm could use different NIDs. For example an RSA key could use the NIDs corresponding to the NIDs NID_rsaEncryption (equivalent to EVP_PKEY_RSA) or NID_rsa (equivalent to EVP_PKEY_RSA2). The use of alternative non-standard NIDs is now rare so EVP_PKEY_RSA2 et al are not often seen in practice. `EVP_PKEY_get_id()` returns -1 (EVP_PKEY_KEYMGMT) if the pkey is only implemented in a provider(7).

`EVP_PKEY_type()` returns the underlying type of the NID type. For example EVP_PKEY_type(EVP_PKEY_RSA2) will return EVP_PKEY_RSA.

EVP_PKEY_set1_RSA(), EVP_PKEY_set1_DSA(), EVP_PKEY_set1_DH() and EVP_PKEY_set1_EC_KEY() set the key referenced by pkey to key. These functions are deprecated. Applications should instead use EVP_PKEY_fromdata(3).

`EVP_PKEY_assign_RSA()`, `EVP_PKEY_assign_DSA()`, `EVP_PKEY_assign_DH()`, `EVP_PKEY_assign_EC_KEY()`, EVP_PKEY_assign_POLY1305() and `EVP_PKEY_assign_SIPHASH()` set the referenced key to key however these use the supplied key internally and so key will be freed when the parent pkey is freed. These macros are deprecated. Applications should instead read an EVP_PKEY directly using the OSSL_DECODER APIs (see OSSL_DECODER_CTX_new_for_pkey(3)), or construct an EVP_PKEY from data using EVP_PKEY_fromdata(3).

EVP_PKEY_get1_RSA(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_DH() and EVP_PKEY_get1_EC_KEY() return the referenced key in pkey or NULL if the key is not of the correct type. The returned key must be freed after use. These functions are deprecated. Applications should instead use the EVP_PKEY directly where possible. If access to the low level key parameters is required then applications should use EVP_PKEY_get_params(3) and other similar functions. To write an EVP_PKEY out use the OSSL_ENCODER APIs (see OSSL_ENCODER_CTX_new_for_pkey(3)).

EVP_PKEY_get0_hmac(), EVP_PKEY_get0_poly1305(), EVP_PKEY_get0_siphash(), EVP_PKEY_get0_RSA(), EVP_PKEY_get0_DSA(), EVP_PKEY_get0_DH() and EVP_PKEY_get0_EC_KEY() return the referenced key in pkey or NULL if the key is not of the correct type. The reference count of the returned key is not incremented and so the key must not be freed after use. These functions are deprecated. Applications should instead use the EVP_PKEY directly where possible. If access to the low level key parameters is required then applications should use EVP_PKEY_get_params(3) and other similar functions. To write an EVP_PKEY out use the OSSL_ENCODER APIs (see OSSL_ENCODER_CTX_new_for_pkey(3)). EVP_PKEY_get0() returns a pointer to the legacy key or NULL if the key is not legacy.

Note that if an EVP_PKEY was not constructed using one of the deprecated functions such as EVP_PKEY_set1_RSA(), EVP_PKEY_set1_DSA(), EVP_PKEY_set1_DH() or EVP_PKEY_set1_EC_KEY(), or via the similarly named EVP_PKEY_assign macros described above then the internal key will be managed by a provider (see provider(7)). In that case the key returned by EVP_PKEY_get1_RSA(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_DH(), EVP_PKEY_get1_EC_KEY(), EVP_PKEY_get0_hmac(), EVP_PKEY_get0_poly1305(), EVP_PKEY_get0_siphash(), EVP_PKEY_get0_RSA(), EVP_PKEY_get0_DSA(), EVP_PKEY_get0_DH() or EVP_PKEY_get0_EC_KEY() will be a cached copy of the provider's key. Subsequent updates to the provider's key will not be reflected back in the cached copy, and updates made by an application to the returned key will not be reflected back in the provider's key. Subsequent calls to EVP_PKEY_get1_RSA(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_DH() and EVP_PKEY_get1_EC_KEY() will always return the cached copy returned by the first call.

EVP_PKEY_get0_engine() returns a reference to the ENGINE handling pkey. This function is deprecated. Applications should use providers instead of engines (see provider(7) for details).

EVP_PKEY_set1_engine() sets the ENGINE handling pkey to engine. It must be called after the key algorithm and components are set up. If engine does not include an EVP_PKEY_METHOD for pkey an error occurs. This function is deprecated. Applications should use providers instead of engines (see provider(7) for details).

# WARNINGS

The following functions are only reliable with EVP_PKEYs that have been assigned an internal key with EVP_PKEY_assign_*():

`EVP_PKEY_get_id()`, `EVP_PKEY_get_base_id()`, `EVP_PKEY_type()`

For EVP_PKEY key type checking purposes, EVP_PKEY_is_a(3) is more generic.

For purposes of retrieving the name of the EVP_PKEY the function EVP_PKEY_get0_type_name(3) is more generally useful.

The keys returned from the functions EVP_PKEY_get0_RSA(), EVP_PKEY_get0_DSA(), EVP_PKEY_get0_DH() and EVP_PKEY_get0_EC_KEY() were changed to have a "const" return type in OpenSSL 3.0. As described above the keys returned may be cached copies of the key held in a provider. Due to this, and unlike in earlier versions of OpenSSL, they should be considered read-only copies of the key. Updates to these keys will not be reflected back in the provider side key. The EVP_PKEY_get1_RSA(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_DH() and EVP_PKEY_get1_EC_KEY() functions were not changed to have a "const" return type in order that applications can "free" the return value. However applications should still consider them as read-only copies.

# NOTES

In accordance with the OpenSSL naming convention the key obtained from or assigned to the pkey using the 1 functions must be freed as well as pkey.

`EVP_PKEY_assign_RSA()`, `EVP_PKEY_assign_DSA()`, `EVP_PKEY_assign_DH()`, `EVP_PKEY_assign_EC_KEY()`, EVP_PKEY_assign_POLY1305() and `EVP_PKEY_assign_SIPHASH()` are implemented as macros.

`EVP_PKEY_assign_EC_KEY()` looks at the curve name id to determine if the passed EC_KEY is an SM2(7) key, and will set the EVP_PKEY type to EVP_PKEY_SM2 in that case, instead of EVP_PKEY_EC.

Most applications wishing to know a key type will simply call `EVP_PKEY_get_base_id()` and will not care about the actual type: which will be identical in almost all cases.

Previous versions of this document suggested using EVP_PKEY_type(pkey->type) to determine the type of a key. Since EVP_PKEY is now opaque this is no longer possible: the equivalent is EVP_PKEY_get_base_id(pkey).

EVP_PKEY_set1_engine() is typically used by an ENGINE returning an HSM key as part of its routine to load a private key.

# RETURN VALUES

EVP_PKEY_set1_RSA(), EVP_PKEY_set1_DSA(), EVP_PKEY_set1_DH() and EVP_PKEY_set1_EC_KEY() return 1 for success or 0 for failure.

EVP_PKEY_get1_RSA(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_DH() and EVP_PKEY_get1_EC_KEY() return the referenced key or NULL if an error occurred.

`EVP_PKEY_assign_RSA()`, `EVP_PKEY_assign_DSA()`, `EVP_PKEY_assign_DH()`, `EVP_PKEY_assign_EC_KEY()`, EVP_PKEY_assign_POLY1305() and `EVP_PKEY_assign_SIPHASH()` return 1 for success and 0 for failure.

`EVP_PKEY_get_base_id()`, `EVP_PKEY_get_id()` and `EVP_PKEY_type()` return a key type or NID_undef (equivalently EVP_PKEY_NONE) on error.

EVP_PKEY_set1_engine() returns 1 for success and 0 for failure.

# SEE ALSO

EVP_PKEY_new(3), SM2(7)

# HISTORY

The `EVP_PKEY_id()` and `EVP_PKEY_base_id()` functions were renamed to include `get` in their names in OpenSSL 3.0, respectively. The old names are kept as non-deprecated alias macros.

EVP_PKEY_set1_RSA, EVP_PKEY_set1_DSA, EVP_PKEY_set1_DH, EVP_PKEY_set1_EC_KEY, EVP_PKEY_get1_RSA, EVP_PKEY_get1_DSA, EVP_PKEY_get1_DH, EVP_PKEY_get1_EC_KEY, EVP_PKEY_get0_RSA, EVP_PKEY_get0_DSA, EVP_PKEY_get0_DH, EVP_PKEY_get0_EC_KEY, EVP_PKEY_assign_RSA, EVP_PKEY_assign_DSA, EVP_PKEY_assign_DH, EVP_PKEY_assign_EC_KEY, EVP_PKEY_assign_POLY1305, EVP_PKEY_assign_SIPHASH, EVP_PKEY_get0_hmac, EVP_PKEY_get0_poly1305, EVP_PKEY_get0_siphash, EVP_PKEY_set1_engine and EVP_PKEY_get0_engine were deprecated in OpenSSL 3.0.

The return value from EVP_PKEY_get0_RSA, EVP_PKEY_get0_DSA, EVP_PKEY_get0_DH, EVP_PKEY_get0_EC_KEY were made const in OpenSSL 3.0.

The function `EVP_PKEY_set_alias_type()` was previously documented on this page. It was removed in OpenSSL 3.0.

# COPYRIGHT

Copyright 2002-2023 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.