OpenSSL.vip

Cryptography and SSL/TLS Toolkit

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

 #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,
                                                  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);

DESCRIPTION

EVP_PKEY_ASN1_METHOD is a structure which holds a set of ASN.1 conversion, printing and information methods for a specific public key algorithm.

There are two places where the EVP_PKEY_ASN1_METHOD 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 Methods

The methods are the underlying implementations of a particular public key algorithm present by the EVP_PKEY object.

 int (*pub_decode) (EVP_PKEY *pk, 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);

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

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

 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);

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

The priv_print() method is called to print a private key in humanly readable text to out, indented indent spaces. It MUST return 0 on error, 1 on success. It's called by int (*pkey_size) (const EVP_PKEY *pk); int (*pkey_bits) (const EVP_PKEY *pk); int (*pkey_security_bits) (const EVP_PKEY *pk);

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

 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);

The param_decode() and param_encode() methods are called to decode / encode DER formatted parameters to / from pk. They MUST return 0 on error, 1 on success. They're called by OSSL_STORE_LOADER(3).

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

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

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

The sig_print() method prints a signature in humanly readable text to out, indented indent spaces. sigalg 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 MUST return 0 on error, 1 on success. It's called by void (*pkey_free) (EVP_PKEY *pkey);

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

 int (*pkey_ctrl) (EVP_PKEY *pkey, int op, long arg1, void *arg2);

The pkey_ctrl() method adds extra algorithm specific control. It's called by EVP_PKEY_supports_digest_nid(3), EVP_PKEY_get1_tls_encodedpoint(3), PKCS7_RECIP_INFO_set(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);

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

 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);

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

item_sign() MUST return one of:

<=0

error

1

item_sign() did everything, OpenSSL internals just needs to pass the signature length back.

2

item_sign() did nothing, OpenSSL internal standard routines are expected to continue with the default signature production.

3

item_sign() set the algorithm identifier algor1 and algor2, OpenSSL internals should just sign using those algorithms.

item_verify() MUST return one of:

<=0

error

1

item_sign() did everything, OpenSSL internals just needs to pass the signature length back.

2

item_sign() did nothing, OpenSSL internal standard routines are expected to continue with the default signature production.

item_verify() and item_sign() are called by ASN1_item_sign(3), and by extension, X509_REQ_verify(3), X509_REQ_sign(3), ...

 int (*siginf_set) (X509_SIG_INFO *siginf, const X509_ALGOR *alg,
                    const ASN1_STRING *sig);

The siginf_set() method is used to set custom X509_SIG_INFO parameters. It MUST return 0 on error, or 1 on success. It's called as part of X509_check_ca(3) and int (*pkey_check) (const EVP_PKEY *pk); int (*pkey_public_check) (const EVP_PKEY *pk); int (*pkey_param_check) (const EVP_PKEY *pk);

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 MUST return 0 for an invalid key, or 1 for a valid key. They are called by EVP_PKEY_public_check(3) and 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);

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

 size_t (*dirty) (const EVP_PKEY *pk);
 void *(*export_to) (const EVP_PKEY *pk, EVP_KEYMGMT *keymgmt);

dirty_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 Functions

EVP_PKEY_asn1_new() creates and returns a new EVP_PKEY_ASN1_METHOD object, and associates the given id, flags, pem_str and info. id is a NID, pem_str is the PEM type string, info is a descriptive string. The following flags are supported:

 ASN1_PKEY_SIGPARAM_NULL

If ASN1_PKEY_SIGPARAM_NULL 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 RETURN VALUES

EVP_PKEY_asn1_new() returns NULL on error, or a pointer to an EVP_PKEY_ASN1_METHOD object otherwise.

EVP_PKEY_asn1_add0() and EVP_PKEY_asn1_add_alias() return 0 on error, or 1 on success.

EVP_PKEY_get0_asn1() returns NULL on error, or a pointer to a constant EVP_PKEY_ASN1_METHOD object otherwise.

COPYRIGHT

Copyright 2017-2018 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.

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