[#ASN1_item_sign_ex]
= ASN1_item_sign_ex
:mrdocs:

Sign the DER encoding of `data` using `it` and write AlgorithmIdentifier(s) plus the signature.

== Synopsis

Declared in `<openssl/asn1.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
ASN1_item_sign_ex(
    xref:ASN1_ITEM.adoc[ASN1_ITEM] const* it,
    xref:X509_ALGOR.adoc[X509_ALGOR]* algor1,
    xref:X509_ALGOR.adoc[X509_ALGOR]* algor2,
    xref:ASN1_BIT_STRING.adoc[ASN1_BIT_STRING]* signature,
    void const* data,
    xref:ASN1_OCTET_STRING.adoc[ASN1_OCTET_STRING] const* id,
    xref:EVP_PKEY.adoc[EVP_PKEY]* pkey,
    xref:EVP_MD.adoc[EVP_MD] const* md,
    xref:OSSL_LIB_CTX.adoc[OSSL_LIB_CTX]* libctx,
    char const* propq);
----

== Return Value

1 on success, or 0 on failure.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *it*
| ASN.1 item describing `data.`
| *algor1*
| First AlgorithmIdentifier to fill (for example signatureAlgorithm), or NULL.
| *algor2*
| Optional second AlgorithmIdentifier to fill, or NULL.
| *signature*
| BIT STRING that receives the signature bytes.
| *data*
| Object whose DER encoding is signed.
| *id*
| Optional ASN.1 OCTET STRING identity / SM2‐id parameter, or NULL.
| *pkey*
| Private key used to create the signature.
| *md*
| Digest method, or NULL to use the key‐type default.
| *libctx*
| Library context for algorithm fetches, or NULL for the default.
| *propq*
| Property query for algorithm fetches, or NULL.
|===


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