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Title "EVP_PKEY_ASN1_METHOD 3ossl"
EVP_PKEY_ASN1_METHOD 3ossl "2023-09-19" "3.0.11" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
EVP_PKEY_ASN1_METHOD, EVP_PKEY_asn1_new, EVP_PKEY_asn1_copy, EVP_PKEY_asn1_free, EVP_PKEY_asn1_add0, EVP_PKEY_asn1_add_alias, EVP_PKEY_asn1_set_public, EVP_PKEY_asn1_set_private, EVP_PKEY_asn1_set_param, EVP_PKEY_asn1_set_free, EVP_PKEY_asn1_set_ctrl, EVP_PKEY_asn1_set_item, EVP_PKEY_asn1_set_siginf, EVP_PKEY_asn1_set_check, EVP_PKEY_asn1_set_public_check, EVP_PKEY_asn1_set_param_check, EVP_PKEY_asn1_set_security_bits, EVP_PKEY_asn1_set_set_priv_key, EVP_PKEY_asn1_set_set_pub_key, EVP_PKEY_asn1_set_get_priv_key, EVP_PKEY_asn1_set_get_pub_key, EVP_PKEY_get0_asn1 \- manipulating and registering EVP_PKEY_ASN1_METHOD structure
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/evp.h> \& typedef struct evp_pkey_asn1_method_st EVP_PKEY_ASN1_METHOD; \& EVP_PKEY_ASN1_METHOD *EVP_PKEY_asn1_new(int id, int flags, const char *pem_str, const char *info); void EVP_PKEY_asn1_copy(EVP_PKEY_ASN1_METHOD *dst, const EVP_PKEY_ASN1_METHOD *src); void EVP_PKEY_asn1_free(EVP_PKEY_ASN1_METHOD *ameth); int EVP_PKEY_asn1_add0(const EVP_PKEY_ASN1_METHOD *ameth); int EVP_PKEY_asn1_add_alias(int to, int from); \& void EVP_PKEY_asn1_set_public(EVP_PKEY_ASN1_METHOD *ameth, int (*pub_decode) (EVP_PKEY *pk, const X509_PUBKEY *pub), int (*pub_encode) (X509_PUBKEY *pub, const EVP_PKEY *pk), int (*pub_cmp) (const EVP_PKEY *a, const EVP_PKEY *b), int (*pub_print) (BIO *out, const EVP_PKEY *pkey, int indent, ASN1_PCTX *pctx), int (*pkey_size) (const EVP_PKEY *pk), int (*pkey_bits) (const EVP_PKEY *pk)); void EVP_PKEY_asn1_set_private(EVP_PKEY_ASN1_METHOD *ameth, int (*priv_decode) (EVP_PKEY *pk, const PKCS8_PRIV_KEY_INFO *p8inf), int (*priv_encode) (PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pk), int (*priv_print) (BIO *out, const EVP_PKEY *pkey, int indent, ASN1_PCTX *pctx)); void EVP_PKEY_asn1_set_param(EVP_PKEY_ASN1_METHOD *ameth, int (*param_decode) (EVP_PKEY *pkey, const unsigned char **pder, int derlen), int (*param_encode) (const EVP_PKEY *pkey, unsigned char **pder), int (*param_missing) (const EVP_PKEY *pk), int (*param_copy) (EVP_PKEY *to, const EVP_PKEY *from), int (*param_cmp) (const EVP_PKEY *a, const EVP_PKEY *b), int (*param_print) (BIO *out, const EVP_PKEY *pkey, int indent, ASN1_PCTX *pctx)); \& void EVP_PKEY_asn1_set_free(EVP_PKEY_ASN1_METHOD *ameth, void (*pkey_free) (EVP_PKEY *pkey)); void EVP_PKEY_asn1_set_ctrl(EVP_PKEY_ASN1_METHOD *ameth, int (*pkey_ctrl) (EVP_PKEY *pkey, int op, long arg1, void *arg2)); void EVP_PKEY_asn1_set_item(EVP_PKEY_ASN1_METHOD *ameth, int (*item_verify) (EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn, X509_ALGOR *a, ASN1_BIT_STRING *sig, EVP_PKEY *pkey), int (*item_sign) (EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn, X509_ALGOR *alg1, X509_ALGOR *alg2, ASN1_BIT_STRING *sig)); \& void EVP_PKEY_asn1_set_siginf(EVP_PKEY_ASN1_METHOD *ameth, int (*siginf_set) (X509_SIG_INFO *siginf, const X509_ALGOR *alg, const ASN1_STRING *sig)); \& void EVP_PKEY_asn1_set_check(EVP_PKEY_ASN1_METHOD *ameth, int (*pkey_check) (const EVP_PKEY *pk)); \& void EVP_PKEY_asn1_set_public_check(EVP_PKEY_ASN1_METHOD *ameth, int (*pkey_pub_check) (const EVP_PKEY *pk)); \& void EVP_PKEY_asn1_set_param_check(EVP_PKEY_ASN1_METHOD *ameth, int (*pkey_param_check) (const EVP_PKEY *pk)); \& void EVP_PKEY_asn1_set_security_bits(EVP_PKEY_ASN1_METHOD *ameth, int (*pkey_security_bits) (const EVP_PKEY *pk)); \& void EVP_PKEY_asn1_set_set_priv_key(EVP_PKEY_ASN1_METHOD *ameth, int (*set_priv_key) (EVP_PKEY *pk, const unsigned char *priv, size_t len)); \& void EVP_PKEY_asn1_set_set_pub_key(EVP_PKEY_ASN1_METHOD *ameth, int (*set_pub_key) (EVP_PKEY *pk, const unsigned char *pub, size_t len)); \& void EVP_PKEY_asn1_set_get_priv_key(EVP_PKEY_ASN1_METHOD *ameth, int (*get_priv_key) (const EVP_PKEY *pk, unsigned char *priv, size_t *len)); \& void EVP_PKEY_asn1_set_get_pub_key(EVP_PKEY_ASN1_METHOD *ameth, int (*get_pub_key) (const EVP_PKEY *pk, unsigned char *pub, size_t *len)); \& const EVP_PKEY_ASN1_METHOD *EVP_PKEY_get0_asn1(const EVP_PKEY *pkey); .Ve
"DESCRIPTION"
Header "DESCRIPTION" \fB\s-1EVP_PKEY_ASN1_METHOD\s0 is a structure which holds a set of \s-1ASN.1\s0 conversion, printing and information methods for a specific public key algorithm.

There are two places where the \s-1EVP_PKEY_ASN1_METHOD\s0 objects are stored: one is a built-in array representing the standard methods for different algorithms, and the other one is a stack of user-defined application-specific methods, which can be manipulated by using \fBEVP_PKEY_asn1_add0\|(3).

"Methods"
Subsection "Methods" The methods are the underlying implementations of a particular public key algorithm present by the \s-1EVP_PKEY\s0 object.

.Vb 5 int (*pub_decode) (EVP_PKEY *pk, const X509_PUBKEY *pub); int (*pub_encode) (X509_PUBKEY *pub, const EVP_PKEY *pk); int (*pub_cmp) (const EVP_PKEY *a, const EVP_PKEY *b); int (*pub_print) (BIO *out, const EVP_PKEY *pkey, int indent, ASN1_PCTX *pctx); .Ve

The pub_decode() and pub_encode() methods are called to decode / encode X509_PUBKEY \s-1ASN.1\s0 parameters to / from pk. They \s-1MUST\s0 return 0 on error, 1 on success. They're called by X509_PUBKEY_get0\|(3) and X509_PUBKEY_set\|(3).

The pub_cmp() method is called when two public keys are to be compared. It \s-1MUST\s0 return 1 when the keys are equal, 0 otherwise. It's called by EVP_PKEY_eq\|(3).

The pub_print() method is called to print a public key in humanly readable text to out, indented indent spaces. It \s-1MUST\s0 return 0 on error, 1 on success. It's called by EVP_PKEY_print_public\|(3).

.Vb 4 int (*priv_decode) (EVP_PKEY *pk, const PKCS8_PRIV_KEY_INFO *p8inf); int (*priv_encode) (PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pk); int (*priv_print) (BIO *out, const EVP_PKEY *pkey, int indent, ASN1_PCTX *pctx); .Ve

The priv_decode() and priv_encode() methods are called to decode / encode \s-1PKCS8_PRIV_KEY_INFO\s0 form private key to / from pk. They \s-1MUST\s0 return 0 on error, 1 on success. They're called by \s-1EVP_PKCS82PKEY\s0\|(3) and \s-1EVP_PKEY2PKCS8\s0\|(3).

The priv_print() method is called to print a private key in humanly readable text to out, indented indent spaces. It \s-1MUST\s0 return 0 on error, 1 on success. It's called by EVP_PKEY_print_private\|(3).

.Vb 3 int (*pkey_size) (const EVP_PKEY *pk); int (*pkey_bits) (const EVP_PKEY *pk); int (*pkey_security_bits) (const EVP_PKEY *pk); .Ve

The pkey_size() method returns the key size in bytes. It's called by EVP_PKEY_get_size\|(3).

The pkey_bits() method returns the key size in bits. It's called by EVP_PKEY_get_bits\|(3).

.Vb 8 int (*param_decode) (EVP_PKEY *pkey, const unsigned char **pder, int derlen); int (*param_encode) (const EVP_PKEY *pkey, unsigned char **pder); int (*param_missing) (const EVP_PKEY *pk); int (*param_copy) (EVP_PKEY *to, const EVP_PKEY *from); int (*param_cmp) (const EVP_PKEY *a, const EVP_PKEY *b); int (*param_print) (BIO *out, const EVP_PKEY *pkey, int indent, ASN1_PCTX *pctx); .Ve

The param_decode() and param_encode() methods are called to decode / encode \s-1DER\s0 formatted parameters to / from pk. They \s-1MUST\s0 return 0 on error, 1 on success. They're called by PEM_read_bio_Parameters\|(3) and the file: \s-1OSSL_STORE_LOADER\s0\|(3).

The param_missing() method returns 0 if a key parameter is missing, otherwise 1. It's called by EVP_PKEY_missing_parameters\|(3).

The param_copy() method copies key parameters from from to to. It \s-1MUST\s0 return 0 on error, 1 on success. It's called by EVP_PKEY_copy_parameters\|(3).

The param_cmp() method compares the parameters of keys a and b. It \s-1MUST\s0 return 1 when the keys are equal, 0 when not equal, or a negative number on error. It's called by EVP_PKEY_parameters_eq\|(3).

The param_print() method prints the private key parameters in humanly readable text to out, indented indent spaces. It \s-1MUST\s0 return 0 on error, 1 on success. It's called by EVP_PKEY_print_params\|(3).

.Vb 3 int (*sig_print) (BIO *out, const X509_ALGOR *sigalg, const ASN1_STRING *sig, int indent, ASN1_PCTX *pctx); .Ve

The sig_print() method prints a signature in humanly readable text to \fBout, indented indent spaces. \fBsigalg contains the exact signature algorithm. If the signature in sig doesn't correspond to what this method expects, X509_signature_dump() must be used as a last resort. It \s-1MUST\s0 return 0 on error, 1 on success. It's called by X509_signature_print\|(3).

.Vb 1 void (*pkey_free) (EVP_PKEY *pkey); .Ve

The pkey_free() method helps freeing the internals of pkey. It's called by EVP_PKEY_free\|(3), EVP_PKEY_set_type\|(3), \fBEVP_PKEY_set_type_str\|(3), and EVP_PKEY_assign\|(3).

.Vb 1 int (*pkey_ctrl) (EVP_PKEY *pkey, int op, long arg1, void *arg2); .Ve

The pkey_ctrl() method adds extra algorithm specific control. It's called by EVP_PKEY_get_default_digest_nid\|(3), \fBEVP_PKEY_set1_encoded_public_key\|(3), \fBEVP_PKEY_get1_encoded_public_key\|(3), PKCS7_SIGNER_INFO_set\|(3), \fBPKCS7_RECIP_INFO_set\|(3), ...

.Vb 3 int (*old_priv_decode) (EVP_PKEY *pkey, const unsigned char **pder, int derlen); int (*old_priv_encode) (const EVP_PKEY *pkey, unsigned char **pder); .Ve

The old_priv_decode() and old_priv_encode() methods decode / encode they private key pkey from / to a \s-1DER\s0 formatted array. These are exclusively used to help decoding / encoding older (pre PKCS#8) \s-1PEM\s0 formatted encrypted private keys. \fBold_priv_decode() \s-1MUST\s0 return 0 on error, 1 on success. \fBold_priv_encode() \s-1MUST\s0 the return same kind of values as \fBi2d_PrivateKey(). They're called by d2i_PrivateKey\|(3) and i2d_PrivateKey\|(3).

.Vb 5 int (*item_verify) (EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn, X509_ALGOR *a, ASN1_BIT_STRING *sig, EVP_PKEY *pkey); int (*item_sign) (EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn, X509_ALGOR *alg1, X509_ALGOR *alg2, ASN1_BIT_STRING *sig); .Ve

The item_sign() and item_verify() methods make it possible to have algorithm specific signatures and verification of them.

\fBitem_sign() \s-1MUST\s0 return one of:

"<=0" 4
Item "<=0" error
"1" 4
Item "1" \fBitem_sign() did everything, OpenSSL internals just needs to pass the signature length back.
"2" 4
Item "2" \fBitem_sign() did nothing, OpenSSL internal standard routines are expected to continue with the default signature production.
"3" 4
Item "3" \fBitem_sign() set the algorithm identifier algor1 and algor2, OpenSSL internals should just sign using those algorithms.

\fBitem_verify() \s-1MUST\s0 return one of:

"<=0" 4
Item "<=0" error
"1" 4
Item "1" \fBitem_sign() did everything, OpenSSL internals just needs to pass the signature length back.
"2" 4
Item "2" \fBitem_sign() did nothing, OpenSSL internal standard routines are expected to continue with the default signature production.

\fBitem_verify() and item_sign() are called by ASN1_item_verify\|(3) and \fBASN1_item_sign\|(3), and by extension, X509_verify\|(3), \fBX509_REQ_verify\|(3), X509_sign\|(3), X509_REQ_sign\|(3), ...

.Vb 2 int (*siginf_set) (X509_SIG_INFO *siginf, const X509_ALGOR *alg, const ASN1_STRING *sig); .Ve

The siginf_set() method is used to set custom X509_SIG_INFO parameters. It \s-1MUST\s0 return 0 on error, or 1 on success. It's called as part of X509_check_purpose\|(3), X509_check_ca\|(3) and X509_check_issued\|(3).

.Vb 3 int (*pkey_check) (const EVP_PKEY *pk); int (*pkey_public_check) (const EVP_PKEY *pk); int (*pkey_param_check) (const EVP_PKEY *pk); .Ve

The pkey_check(), pkey_public_check() and pkey_param_check() methods are used to check the validity of pk for key-pair, public component and parameters, respectively. They \s-1MUST\s0 return 0 for an invalid key, or 1 for a valid key. They are called by EVP_PKEY_check\|(3), EVP_PKEY_public_check\|(3) and \fBEVP_PKEY_param_check\|(3) respectively.

.Vb 2 int (*set_priv_key) (EVP_PKEY *pk, const unsigned char *priv, size_t len); int (*set_pub_key) (EVP_PKEY *pk, const unsigned char *pub, size_t len); .Ve

The set_priv_key() and set_pub_key() methods are used to set the raw private and public key data for an \s-1EVP_PKEY.\s0 They \s-1MUST\s0 return 0 on error, or 1 on success. They are called by EVP_PKEY_new_raw_private_key\|(3), and \fBEVP_PKEY_new_raw_public_key\|(3) respectively.

.Vb 2 size_t (*dirty) (const EVP_PKEY *pk); void *(*export_to) (const EVP_PKEY *pk, EVP_KEYMGMT *keymgmt); .Ve

\fBdirty_cnt() returns the internal key's dirty count. This can be used to synchronise different copies of the same keys.

The export_to() method exports the key material from the given key to a provider, through the \s-1EVP_KEYMGMT\s0\|(3) interface, if that provider supports importing key material.

"Functions"
Subsection "Functions" \fBEVP_PKEY_asn1_new() creates and returns a new \s-1EVP_PKEY_ASN1_METHOD\s0 object, and associates the given id, flags, pem_str and \fBinfo. \fBid is a \s-1NID,\s0 pem_str is the \s-1PEM\s0 type string, info is a descriptive string. The following flags are supported:

.Vb 1 ASN1_PKEY_SIGPARAM_NULL .Ve

If \s-1ASN1_PKEY_SIGPARAM_NULL\s0 is set, then the signature algorithm parameters are given the type V_ASN1_NULL by default, otherwise they will be given the type V_ASN1_UNDEF (i.e. the parameter is omitted). See X509_ALGOR_set0\|(3) for more information.

\fBEVP_PKEY_asn1_copy() copies an \s-1EVP_PKEY_ASN1_METHOD\s0 object from \fBsrc to dst. This function is not thread safe, it's recommended to only use this when initializing the application.

\fBEVP_PKEY_asn1_free() frees an existing \s-1EVP_PKEY_ASN1_METHOD\s0 pointed by ameth.

\fBEVP_PKEY_asn1_add0() adds ameth to the user defined stack of methods unless another \s-1EVP_PKEY_ASN1_METHOD\s0 with the same \s-1NID\s0 is already there. This function is not thread safe, it's recommended to only use this when initializing the application.

\fBEVP_PKEY_asn1_add_alias() creates an alias with the \s-1NID\s0 to for the \fB\s-1EVP_PKEY_ASN1_METHOD\s0 with \s-1NID\s0 from unless another \fB\s-1EVP_PKEY_ASN1_METHOD\s0 with the same \s-1NID\s0 is already added. This function is not thread safe, it's recommended to only use this when initializing the application.

\fBEVP_PKEY_asn1_set_public(), EVP_PKEY_asn1_set_private(), \fBEVP_PKEY_asn1_set_param(), EVP_PKEY_asn1_set_free(), \fBEVP_PKEY_asn1_set_ctrl(), EVP_PKEY_asn1_set_item(), \fBEVP_PKEY_asn1_set_siginf(), EVP_PKEY_asn1_set_check(), \fBEVP_PKEY_asn1_set_public_check(), EVP_PKEY_asn1_set_param_check(), \fBEVP_PKEY_asn1_set_security_bits(), EVP_PKEY_asn1_set_set_priv_key(), \fBEVP_PKEY_asn1_set_set_pub_key(), EVP_PKEY_asn1_set_get_priv_key() and \fBEVP_PKEY_asn1_set_get_pub_key() set the diverse methods of the given \fB\s-1EVP_PKEY_ASN1_METHOD\s0 object.

\fBEVP_PKEY_get0_asn1() finds the \s-1EVP_PKEY_ASN1_METHOD\s0 associated with the key pkey.

"RETURN VALUES"
Header "RETURN VALUES" \fBEVP_PKEY_asn1_new() returns \s-1NULL\s0 on error, or a pointer to an \fB\s-1EVP_PKEY_ASN1_METHOD\s0 object otherwise.

\fBEVP_PKEY_asn1_add0() and EVP_PKEY_asn1_add_alias() return 0 on error, or 1 on success.

\fBEVP_PKEY_get0_asn1() returns \s-1NULL\s0 on error, or a pointer to a constant \fB\s-1EVP_PKEY_ASN1_METHOD\s0 object otherwise.

"HISTORY"
Header "HISTORY" The signature of the pub_decode functional argument of \fBEVP_PKEY_asn1_set_public() has changed in OpenSSL 3.0 so its pub parameter is now constified.
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2017-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.