path: root/lib/libcrypto/man/EVP_PKEY_asn1_get_count.3

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.Dd $Mdocdate: September 13 2023 $
.Dt EVP_PKEY_ASN1_GET_COUNT 3
.Os
.Sh NAME
.Nm EVP_PKEY_asn1_get_count ,
.Nm EVP_PKEY_asn1_get0 ,
.Nm EVP_PKEY_get0_asn1 ,
.Nm EVP_PKEY_asn1_find ,
.Nm EVP_PKEY_asn1_find_str ,
.Nm EVP_PKEY_asn1_get0_info
.Nd enumerate public key ASN.1 methods
.Sh SYNOPSIS
.In openssl/evp.h
.Ft int
.Fn EVP_PKEY_asn1_get_count void
.Ft const EVP_PKEY_ASN1_METHOD *
.Fo EVP_PKEY_asn1_get0
.Fa "int idx"
.Fc
.Ft const EVP_PKEY_ASN1_METHOD *
.Fo EVP_PKEY_get0_asn1
.Fa "const EVP_PKEY *pkey"
.Fc
.Ft const EVP_PKEY_ASN1_METHOD *
.Fo EVP_PKEY_asn1_find
.Fa "ENGINE **pe"
.Fa "int type"
.Fc
.Ft const EVP_PKEY_ASN1_METHOD *
.Fo EVP_PKEY_asn1_find_str
.Fa "ENGINE **pe"
.Fa "const char *str"
.Fa "int len"
.Fc
.Ft int
.Fo EVP_PKEY_asn1_get0_info
.Fa "int *ppkey_id"
.Fa "int *pkey_base_id"
.Fa "int *ppkey_flags"
.Fa "const char **pinfo"
.Fa "const char **ppem_str"
.Fa "const EVP_PKEY_ASN1_METHOD *ameth"
.Fc
.Sh DESCRIPTION
.Fn EVP_PKEY_asn1_get_count
returns the number of public key ASN.1 methods available.
It includes standard methods and any methods added by the application.
.Pp
.Fn EVP_PKEY_asn1_get0
returns the public key ASN.1 method
.Fa idx .
The value of
.Fa idx
must be in the range from zero to
.Fn EVP_PKEY_asn1_get_count
\- 1.
.Pp
.Fn EVP_PKEY_asn1_find
looks up the method with NID
.Fa type ,
which can be any of the values that
.Xr EVP_PKEY_base_id 3
and
.Xr EVP_PKEY_id 3
may return.
If
.Fa pe
is not
.Dv NULL ,
it first looks for an engine implementing a method for the NID
.Fa type .
If one is found,
.Pf * Fa pe
is set to that engine and the method from that engine is returned instead.
.Pp
.Fn EVP_PKEY_asn1_find_str
looks up the method with the PEM type string given by the first
.Fa len
bytes of
.Fa str .
If
.Fa len
is \-1, the
.Xr strlen 3
of
.Fa str
is used instead.
The PEM type strings supported by default are listed in the
.Xr EVP_PKEY_base_id 3
manual page.
Just like
.Fn EVP_PKEY_asn1_find ,
if
.Fa pe
is not
.Dv NULL ,
methods from engines are preferred.
.Pp
.Fn EVP_PKEY_asn1_get0_info
retrieves the public key ID as returned by
.Xr EVP_PKEY_id 3 ,
the base public key ID as returned by
.Xr EVP_PKEY_base_id 3
.Pq both NIDs ,
any flags, and internal pointers owned by
.Fa ameth
pointing to its method description string and its PEM type string.
.Pp
The following flags bits can occur, OR'ed together in
.Pf * Fa ppkey_flags :
.Bl -tag -width Ds
.It Dv ASN1_PKEY_ALIAS
This
.Fa ameth
object serves as an alias for another
.Vt EVP_PKEY_ASN1_METHOD
object and will never be returned from
.Fn EVP_PKEY_asn1_find
or
.Fn EVP_PKEY_asn1_find_str .
It is either an alias built into the library, or it was created with
.Xr EVP_PKEY_asn1_add_alias 3 .
.It Dv ASN1_PKEY_DYNAMIC
This
.Fa ameth
object is marked as dynamically allocated.
If this flag is set,
.Xr EVP_PKEY_asn1_free 3
can free
.Fa ameth ;
otherwise,
.Xr EVP_PKEY_asn1_free 3
has no effect on it.
.It Dv ASN1_PKEY_SIGPARAM_NULL
If the signing
.Fa ctx
uses an
.Vt EVP_PKEY
private key associated with this
.Fa ameth ,
instruct
.Xr ASN1_item_sign_ctx 3
to use a parameter type of
.Dv V_ASN1_NULL
instead of the default
.Dv V_ASN1_UNDEF
when encoding the ASN.1
.Vt AlgorithmIdentifier
objects with
.Xr X509_ALGOR_set0 3 .
In particular, this is used for
.Dv EVP_PKEY_RSA .
.El
.Pp
.Fn EVP_PKEY_asn1_get_count ,
.Fn EVP_PKEY_asn1_get0 ,
.Fn EVP_PKEY_asn1_find
and
.Fn EVP_PKEY_asn1_find_str
are not thread safe, but as long as all
.Vt EVP_PKEY_ASN1_METHOD
objects are added before the application gets threaded, using them is
safe.
See
.Xr EVP_PKEY_asn1_add0 3 .
.Sh RETURN VALUES
.Fn EVP_PKEY_asn1_get_count
returns the number of available public key methods.
.Pp
.Fn EVP_PKEY_asn1_get0
returns a public key method or
.Dv NULL
if
.Fa idx
is out of range.
.Pp
.Fn EVP_PKEY_get0_asn1
returns the public key method used by
.Fa pkey .
.Pp
.Fn EVP_PKEY_asn1_find
and
.Fn EVP_PKEY_asn1_find_str
return a matching public key method or
.Dv NULL
if no match is found.
.Pp
.Fn EVP_PKEY_asn1_get0_info
returns 1 on success or 0 on failure.
.Sh SEE ALSO
.Xr EVP_PKEY_asn1_new 3 ,
.Xr EVP_PKEY_base_id 3 ,
.Xr EVP_PKEY_new 3
.Sh HISTORY
These functions first appeared in OpenSSL 1.0.0
and have been available since
.Ox 4.9 .