[#EVP_PKEY_CTX_set_hkdf_mode]
= EVP_PKEY_CTX_set_hkdf_mode
:mrdocs:

Select HKDF extract/expand mode on a key‐derivation EVP_PKEY_CTX.

== Synopsis

Declared in `<openssl/kdf.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
EVP_PKEY_CTX_set_hkdf_mode(
    xref:EVP_PKEY_CTX.adoc[EVP_PKEY_CTX]* ctx,
    int mode);
----

== Return Value

1 on success, or 0 on error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *ctx*
| HKDF derivation context.
| *mode*
| EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND, EXTRACT_ONLY, or EXPAND_ONLY.
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#