evp.h

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#ifndef OPENSSL_HEADER_EVP_H
#define OPENSSL_HEADER_EVP_H

#include <openssl/base.h>

#include <openssl/evp_errors.h>  // IWYU pragma: export
#include <openssl/thread.h>

// OpenSSL included digest, cipher, and object functions in this header so we
// include them for users that still expect that.
#include <openssl/aead.h>
#include <openssl/base64.h>
#include <openssl/cipher.h>
#include <openssl/digest.h>
#include <openssl/nid.h>
#include <openssl/objects.h>

#if defined(__cplusplus)
extern "C" {
#endif


// EVP abstracts over public/private key algorithms.


// Public key objects.
//
// An |EVP_PKEY| object represents a public or private key. A given object may
// be used concurrently on multiple threads by non-mutating functions, provided
// no other thread is concurrently calling a mutating function. Unless otherwise
// documented, functions which take a |const| pointer are non-mutating and
// functions which take a non-|const| pointer are mutating.

// EVP_PKEY_new creates a new, empty public-key object and returns it or NULL
// on allocation failure.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_new(void);

// EVP_PKEY_free frees all data referenced by |pkey| and then frees |pkey|
// itself.
OPENSSL_EXPORT void EVP_PKEY_free(EVP_PKEY *pkey);

// EVP_PKEY_up_ref increments the reference count of |pkey| and returns one. It
// does not mutate |pkey| for thread-safety purposes and may be used
// concurrently.
OPENSSL_EXPORT int EVP_PKEY_up_ref(EVP_PKEY *pkey);

// EVP_PKEY_is_opaque returns one if |pkey| is opaque. Opaque keys are backed by
// custom implementations which do not expose key material and parameters. It is
// an error to attempt to duplicate, export, or compare an opaque key.
OPENSSL_EXPORT int EVP_PKEY_is_opaque(const EVP_PKEY *pkey);

// EVP_PKEY_cmp compares |a| and |b| and returns one if they are equal, zero if
// not and a negative number on error.
//
// WARNING: this differs from the traditional return value of a "cmp"
// function.
OPENSSL_EXPORT int EVP_PKEY_cmp(const EVP_PKEY *a, const EVP_PKEY *b);

// EVP_PKEY_copy_parameters sets the parameters of |to| to equal the parameters
// of |from|. It returns one on success and zero on error.
OPENSSL_EXPORT int EVP_PKEY_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from);

// EVP_PKEY_missing_parameters returns one if |pkey| is missing needed
// parameters or zero if not, or if the algorithm doesn't take parameters.
OPENSSL_EXPORT int EVP_PKEY_missing_parameters(const EVP_PKEY *pkey);

// EVP_PKEY_size returns the maximum size, in bytes, of a signature signed by
// |pkey|. For an RSA key, this returns the number of bytes needed to represent
// the modulus. For an EC key, this returns the maximum size of a DER-encoded
// ECDSA signature. For an ML-DSA key, this returns the signature byte size.
OPENSSL_EXPORT int EVP_PKEY_size(const EVP_PKEY *pkey);

// EVP_PKEY_bits returns the "size", in bits, of |pkey|. For an RSA key, this
// returns the bit length of the modulus. For an EC key, this returns the bit
// length of the group order. For an ML-DSA key, this returns the bit length
// of the public key.
OPENSSL_EXPORT int EVP_PKEY_bits(const EVP_PKEY *pkey);

// EVP_PKEY_id returns the type of |pkey|, which is one of the |EVP_PKEY_*|
// values.
OPENSSL_EXPORT int EVP_PKEY_id(const EVP_PKEY *pkey);

// EVP_PKEY_type returns |nid| if |nid| is a known key type and |NID_undef|
// otherwise.
OPENSSL_EXPORT int EVP_PKEY_type(int nid);

// EVP_MD_get0_name returns the short name of |md|
OPENSSL_EXPORT const char *EVP_MD_get0_name(const EVP_MD *md);

// EVP_MD_name calls |EVP_MD_get0_name|
OPENSSL_EXPORT const char *EVP_MD_name(const EVP_MD *md);

// Getting and setting concrete public key types.
//
// The following functions get and set the underlying public key in an
// |EVP_PKEY| object. The |set1| functions take an additional reference to the
// underlying key and return one on success or zero if |key| is NULL. The
// |assign| functions adopt the caller's reference and return one on success or
// zero if |key| is NULL. The |get1| functions return a fresh reference to the
// underlying object or NULL if |pkey| is not of the correct type. The |get0|
// functions behave the same but return a non-owning pointer.
//
// The |get0| and |get1| functions take |const| pointers and are thus
// non-mutating for thread-safety purposes, but mutating functions on the
// returned lower-level objects are considered to also mutate the |EVP_PKEY| and
// may not be called concurrently with other operations on the |EVP_PKEY|.

OPENSSL_EXPORT int EVP_PKEY_set1_RSA(EVP_PKEY *pkey, RSA *key);
OPENSSL_EXPORT int EVP_PKEY_assign_RSA(EVP_PKEY *pkey, RSA *key);
OPENSSL_EXPORT RSA *EVP_PKEY_get0_RSA(const EVP_PKEY *pkey);
OPENSSL_EXPORT RSA *EVP_PKEY_get1_RSA(const EVP_PKEY *pkey);

OPENSSL_EXPORT int EVP_PKEY_set1_DSA(EVP_PKEY *pkey, DSA *key);
OPENSSL_EXPORT int EVP_PKEY_assign_DSA(EVP_PKEY *pkey, DSA *key);
OPENSSL_EXPORT DSA *EVP_PKEY_get0_DSA(const EVP_PKEY *pkey);
OPENSSL_EXPORT DSA *EVP_PKEY_get1_DSA(const EVP_PKEY *pkey);

OPENSSL_EXPORT int EVP_PKEY_set1_EC_KEY(EVP_PKEY *pkey, EC_KEY *key);
OPENSSL_EXPORT int EVP_PKEY_assign_EC_KEY(EVP_PKEY *pkey, EC_KEY *key);
OPENSSL_EXPORT EC_KEY *EVP_PKEY_get0_EC_KEY(const EVP_PKEY *pkey);
OPENSSL_EXPORT EC_KEY *EVP_PKEY_get1_EC_KEY(const EVP_PKEY *pkey);

OPENSSL_EXPORT int EVP_PKEY_set1_DH(EVP_PKEY *pkey, DH *key);
OPENSSL_EXPORT int EVP_PKEY_assign_DH(EVP_PKEY *pkey, DH *key);
OPENSSL_EXPORT DH *EVP_PKEY_get0_DH(const EVP_PKEY *pkey);
OPENSSL_EXPORT DH *EVP_PKEY_get1_DH(const EVP_PKEY *pkey);

// EVP_PKEY_CTX_set_dh_paramgen_prime_len sets the length of the DH prime
// parameter p for DH parameter generation. If this function is not called,
// the default length of 2048 is used. |pbits| must be greater than or equal
// to 256. Returns 1 on success, otherwise returns a non-positive value.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int pbits);

// EVP_PKEY_CTX_set_dh_paramgen_generator sets the DH generator for DH parameter
// generation. If this function is not called, the default value of 2 is used.
// |gen| must be greater than 1. Returns 1 on success, otherwise returns a
// non-positive value.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);

#define EVP_PKEY_NONE NID_undef
#define EVP_PKEY_RSA NID_rsaEncryption
#define EVP_PKEY_RSA_PSS NID_rsassaPss
#define EVP_PKEY_EC NID_X9_62_id_ecPublicKey
#define EVP_PKEY_ED25519 NID_ED25519
#define EVP_PKEY_X25519 NID_X25519
#define EVP_PKEY_HKDF NID_hkdf
#define EVP_PKEY_HMAC NID_hmac
#define EVP_PKEY_DH NID_dhKeyAgreement

#ifdef ENABLE_DILITHIUM
#define EVP_PKEY_NISTDSA NID_NISTDSA
#endif

#define EVP_PKEY_KEM NID_kem

// EVP_PKEY_set_type sets the type of |pkey| to |type|. It returns one if
// successful or zero if the |type| argument is not one of the |EVP_PKEY_*|
// values. If |pkey| is NULL, it simply reports whether the type is known.
OPENSSL_EXPORT int EVP_PKEY_set_type(EVP_PKEY *pkey, int type);

// EVP_PKEY_cmp_parameters compares the parameters of |a| and |b|. It returns
// one if they match, zero if not, or a negative number of on error.
//
// WARNING: the return value differs from the usual return value convention.
OPENSSL_EXPORT int EVP_PKEY_cmp_parameters(const EVP_PKEY *a,
                                           const EVP_PKEY *b);


// ASN.1 functions

// EVP_parse_public_key decodes a DER-encoded SubjectPublicKeyInfo structure
// (RFC 5280) from |cbs| and advances |cbs|. It returns a newly-allocated
// |EVP_PKEY| or NULL on error. If the key is an EC key, the curve is guaranteed
// to be set.
//
// The caller must check the type of the parsed public key to ensure it is
// suitable and validate other desired key properties such as RSA modulus size
// or EC curve.
OPENSSL_EXPORT EVP_PKEY *EVP_parse_public_key(CBS *cbs);

// EVP_marshal_public_key marshals |key| as a DER-encoded SubjectPublicKeyInfo
// structure (RFC 5280) and appends the result to |cbb|. It returns one on
// success and zero on error.
OPENSSL_EXPORT int EVP_marshal_public_key(CBB *cbb, const EVP_PKEY *key);

// EVP_parse_private_key decodes a DER-encoded PrivateKeyInfo structure (RFC
// 5208) from |cbs| and advances |cbs|. It returns a newly-allocated |EVP_PKEY|
// or NULL on error.
//
// The caller must check the type of the parsed private key to ensure it is
// suitable and validate other desired key properties such as RSA modulus size
// or EC curve. In particular, RSA private key operations scale cubicly, so
// applications accepting RSA private keys from external sources may need to
// bound key sizes (use |EVP_PKEY_bits| or |RSA_bits|) to avoid a DoS vector.
//
// A PrivateKeyInfo ends with an optional set of attributes. These are not
// processed and so this function will silently ignore any trailing data in the
// structure.
OPENSSL_EXPORT EVP_PKEY *EVP_parse_private_key(CBS *cbs);

// EVP_marshal_private_key marshals |key| as a DER-encoded PrivateKeyInfo
// structure (RFC 5208) and appends the result to |cbb|. It returns one on
// success and zero on error.
OPENSSL_EXPORT int EVP_marshal_private_key(CBB *cbb, const EVP_PKEY *key);

// EVP_marshal_private_key_v2 marshals |key| as a DER-encoded
// OneAsymmetricKey (RFC 5958) and appends the result to |cbb|. It returns one
// on success and zero on error.
//
// Ed25519 and x25119 are the only private key that supports marshaling as a v2
// PKCS8 structure. All other private key types will return
// UNSUPPORTED_ALGORITHM error.
OPENSSL_EXPORT int EVP_marshal_private_key_v2(CBB *cbb, const EVP_PKEY *key);

// Raw keys
//
// Some keys types support a "raw" serialization. Currently the only supported
// raw formats are X25519 and Ed25519, where the formats are those specified in
// RFC 7748 and RFC 8032, respectively. Note the RFC 8032 private key format
// is the 32-byte prefix of |ED25519_sign|'s 64-byte private key.
// For ML-DSA the public key and private key formats are those specified
// in draft-ietf-lamps-dilithium-certificates-00 and the ML-DSA specification.

// EVP_PKEY_new_raw_private_key returns a newly allocated |EVP_PKEY| wrapping a
// private key of the specified type. It returns NULL on error.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_new_raw_private_key(int type, ENGINE *unused,
                                                      const uint8_t *in,
                                                      size_t len);

// EVP_PKEY_new_raw_public_key returns a newly allocated |EVP_PKEY| wrapping a
// public key of the specified type. It returns NULL on error.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_new_raw_public_key(int type, ENGINE *unused,
                                                     const uint8_t *in,
                                                     size_t len);

// EVP_PKEY_get_raw_private_key outputs the private key for |pkey| in raw form.
// If |out| is NULL, it sets |*out_len| to the size of the raw private key.
// Otherwise, it writes at most |*out_len| bytes to |out| and sets |*out_len| to
// the number of bytes written.
//
// It returns one on success and zero if |pkey| has no private key, the key
// type does not support a raw format, or the buffer is too small.
OPENSSL_EXPORT int EVP_PKEY_get_raw_private_key(const EVP_PKEY *pkey,
                                                uint8_t *out, size_t *out_len);

// EVP_PKEY_get_raw_public_key outputs the public key for |pkey| in raw form.
// If |out| is NULL, it sets |*out_len| to the size of the raw public key.
// Otherwise, it writes at most |*out_len| bytes to |out| and sets |*out_len| to
// the number of bytes written.
//
// It returns one on success and zero if |pkey| has no public key, the key
// type does not support a raw format, or the buffer is too small.
OPENSSL_EXPORT int EVP_PKEY_get_raw_public_key(const EVP_PKEY *pkey,
                                               uint8_t *out, size_t *out_len);


// Signing

// EVP_DigestSignInit sets up |ctx| for a signing operation with |type| and
// |pkey|. The |ctx| argument must have been initialised with
// |EVP_MD_CTX_init|. If |pctx| is not NULL, the |EVP_PKEY_CTX| of the signing
// operation will be written to |*pctx|; this can be used to set alternative
// signing options.
//
// For single-shot signing algorithms which do not use a pre-hash, such as
// Ed25519 and ML-DSA, |type| should be NULL. The |EVP_MD_CTX| itself is
// unused but is present so the API is uniform. See |EVP_DigestSign|.
//
// This function does not mutate |pkey| for thread-safety purposes and may be
// used concurrently with other non-mutating functions on |pkey|.
//
// It returns one on success, or zero on error.
OPENSSL_EXPORT int EVP_DigestSignInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
                                      const EVP_MD *type, ENGINE *e,
                                      EVP_PKEY *pkey);

// EVP_DigestSignUpdate appends |len| bytes from |data| to the data which will
// be signed in |EVP_DigestSignFinal|. It returns one.
//
// This function performs a streaming signing operation and will fail for
// signature algorithms which do not support this. Use |EVP_DigestSign| for a
// single-shot operation.
OPENSSL_EXPORT int EVP_DigestSignUpdate(EVP_MD_CTX *ctx, const void *data,
                                        size_t len);

// EVP_DigestSignFinal signs the data that has been included by one or more
// calls to |EVP_DigestSignUpdate|. If |out_sig| is NULL then |*out_sig_len| is
// set to the maximum number of output bytes. Otherwise, on entry,
// |*out_sig_len| must contain the length of the |out_sig| buffer. If the call
// is successful, the signature is written to |out_sig| and |*out_sig_len| is
// set to its length.
//
// This function performs a streaming signing operation and will fail for
// signature algorithms which do not support this. Use |EVP_DigestSign| for a
// single-shot operation.
//
// It returns one on success, or zero on error.
OPENSSL_EXPORT int EVP_DigestSignFinal(EVP_MD_CTX *ctx, uint8_t *out_sig,
                                       size_t *out_sig_len);

// EVP_DigestSign signs |data_len| bytes from |data| using |ctx|. If |out_sig|
// is NULL then |*out_sig_len| is set to the maximum number of output
// bytes. Otherwise, on entry, |*out_sig_len| must contain the length of the
// |out_sig| buffer. If the call is successful, the signature is written to
// |out_sig| and |*out_sig_len| is set to its length.
//
// It returns one on success and zero on error.
OPENSSL_EXPORT int EVP_DigestSign(EVP_MD_CTX *ctx, uint8_t *out_sig,
                                  size_t *out_sig_len, const uint8_t *data,
                                  size_t data_len);


// Verifying

// EVP_DigestVerifyInit sets up |ctx| for a signature verification operation
// with |type| and |pkey|. The |ctx| argument must have been initialised with
// |EVP_MD_CTX_init|. If |pctx| is not NULL, the |EVP_PKEY_CTX| of the signing
// operation will be written to |*pctx|; this can be used to set alternative
// signing options.
//
// For single-shot signing algorithms which do not use a pre-hash, such as
// Ed25519 and ML-DSA, |type| should be NULL. The |EVP_MD_CTX| itself is
// unused but is present so the API is uniform. See |EVP_DigestVerify|.
//
// This function does not mutate |pkey| for thread-safety purposes and may be
// used concurrently with other non-mutating functions on |pkey|.
//
// It returns one on success, or zero on error.
OPENSSL_EXPORT int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
                                        const EVP_MD *type, ENGINE *e,
                                        EVP_PKEY *pkey);

// EVP_DigestVerifyUpdate appends |len| bytes from |data| to the data which
// will be verified by |EVP_DigestVerifyFinal|. It returns one.
//
// This function performs streaming signature verification and will fail for
// signature algorithms which do not support this. Use |EVP_PKEY_verify_message|
// for a single-shot verification.
OPENSSL_EXPORT int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *data,
                                          size_t len);

// EVP_DigestVerifyFinal verifies that |sig_len| bytes of |sig| are a valid
// signature for the data that has been included by one or more calls to
// |EVP_DigestVerifyUpdate|. It returns one on success and zero otherwise.
//
// This function performs streaming signature verification and will fail for
// signature algorithms which do not support this. Use |EVP_PKEY_verify_message|
// for a single-shot verification.
OPENSSL_EXPORT int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const uint8_t *sig,
                                         size_t sig_len);

// EVP_DigestVerify verifies that |sig_len| bytes from |sig| are a valid
// signature for |data|. It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_DigestVerify(EVP_MD_CTX *ctx, const uint8_t *sig,
                                    size_t sig_len, const uint8_t *data,
                                    size_t len);


// Signing (old functions)

// EVP_SignInit_ex configures |ctx|, which must already have been initialised,
// for a fresh signing operation using the hash function |type|. It returns one
// on success and zero otherwise.
//
// (In order to initialise |ctx|, either obtain it initialised with
// |EVP_MD_CTX_create|, or use |EVP_MD_CTX_init|.)
OPENSSL_EXPORT int EVP_SignInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type,
                                   ENGINE *impl);

// EVP_SignInit is a deprecated version of |EVP_SignInit_ex|.
//
// TODO(fork): remove.
OPENSSL_EXPORT int EVP_SignInit(EVP_MD_CTX *ctx, const EVP_MD *type);

// EVP_SignUpdate appends |len| bytes from |data| to the data which will be
// signed in |EVP_SignFinal|.
OPENSSL_EXPORT int EVP_SignUpdate(EVP_MD_CTX *ctx, const void *data,
                                  size_t len);

// EVP_SignFinal signs the data that has been included by one or more calls to
// |EVP_SignUpdate|, using the key |pkey|, and writes it to |sig|. On entry,
// |sig| must point to at least |EVP_PKEY_size(pkey)| bytes of space. The
// actual size of the signature is written to |*out_sig_len|.
//
// It returns one on success and zero otherwise.
//
// It does not modify |ctx|, thus it's possible to continue to use |ctx| in
// order to sign a longer message. It also does not mutate |pkey| for
// thread-safety purposes and may be used concurrently with other non-mutating
// functions on |pkey|.
OPENSSL_EXPORT int EVP_SignFinal(const EVP_MD_CTX *ctx, uint8_t *sig,
                                 unsigned int *out_sig_len, EVP_PKEY *pkey);


// Verifying (old functions)

// EVP_VerifyInit_ex configures |ctx|, which must already have been
// initialised, for a fresh signature verification operation using the hash
// function |type|. It returns one on success and zero otherwise.
//
// (In order to initialise |ctx|, either obtain it initialised with
// |EVP_MD_CTX_create|, or use |EVP_MD_CTX_init|.)
OPENSSL_EXPORT int EVP_VerifyInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type,
                                     ENGINE *impl);

// EVP_VerifyInit is a deprecated version of |EVP_VerifyInit_ex|.
//
// TODO(fork): remove.
OPENSSL_EXPORT int EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type);

// EVP_VerifyUpdate appends |len| bytes from |data| to the data which will be
// signed in |EVP_VerifyFinal|.
OPENSSL_EXPORT int EVP_VerifyUpdate(EVP_MD_CTX *ctx, const void *data,
                                    size_t len);

// EVP_VerifyFinal verifies that |sig_len| bytes of |sig| are a valid
// signature, by |pkey|, for the data that has been included by one or more
// calls to |EVP_VerifyUpdate|.
//
// It returns one on success and zero otherwise.
//
// It does not modify |ctx|, thus it's possible to continue to use |ctx| in
// order to verify a longer message. It also does not mutate |pkey| for
// thread-safety purposes and may be used concurrently with other non-mutating
// functions on |pkey|.
OPENSSL_EXPORT int EVP_VerifyFinal(EVP_MD_CTX *ctx, const uint8_t *sig,
                                   size_t sig_len, EVP_PKEY *pkey);


// Printing

// EVP_PKEY_print_public prints a textual representation of the public key in
// |pkey| to |out|. Returns one on success or zero otherwise.
OPENSSL_EXPORT int EVP_PKEY_print_public(BIO *out, const EVP_PKEY *pkey,
                                         int indent, ASN1_PCTX *pctx);

// EVP_PKEY_print_private prints a textual representation of the private key in
// |pkey| to |out|. Returns one on success or zero otherwise.
OPENSSL_EXPORT int EVP_PKEY_print_private(BIO *out, const EVP_PKEY *pkey,
                                          int indent, ASN1_PCTX *pctx);

// EVP_PKEY_print_params prints a textual representation of the parameters in
// |pkey| to |out|. Returns one on success or zero otherwise.
OPENSSL_EXPORT int EVP_PKEY_print_params(BIO *out, const EVP_PKEY *pkey,
                                         int indent, ASN1_PCTX *pctx);


// Password stretching.
//
// Password stretching functions take a low-entropy password and apply a slow
// function that results in a key suitable for use in symmetric
// cryptography.

#define PKCS5_SALT_LEN 8

// PKCS5_PBKDF2_HMAC computes |iterations| iterations of PBKDF2 of |password|
// and |salt|, using |digest|, and outputs |key_len| bytes to |out_key|. It
// returns one on success and zero on allocation failure or if |iterations| is
// 0. It's recommended that |iterations| be set to a much higher number (at
// least hundreds of thousands).
OPENSSL_EXPORT int PKCS5_PBKDF2_HMAC(const char *password, size_t password_len,
                                     const uint8_t *salt, size_t salt_len,
                                     uint32_t iterations, const EVP_MD *digest,
                                     size_t key_len, uint8_t *out_key);

// PKCS5_PBKDF2_HMAC_SHA1 is the same as PKCS5_PBKDF2_HMAC, but with |digest|
// fixed to |EVP_sha1|.
OPENSSL_EXPORT int PKCS5_PBKDF2_HMAC_SHA1(const char *password,
                                          size_t password_len,
                                          const uint8_t *salt, size_t salt_len,
                                          uint32_t iterations, size_t key_len,
                                          uint8_t *out_key);

// EVP_PBE_scrypt expands |password| into a secret key of length |key_len| using
// scrypt, as described in RFC 7914, and writes the result to |out_key|. It
// returns one on success and zero on allocation failure, if the memory required
// for the operation exceeds |max_mem|, or if any of the parameters are invalid
// as described below.
//
// |N|, |r|, and |p| are as described in RFC 7914 section 6. They determine the
// cost of the operation. If |max_mem| is zero, a defult limit of 32MiB will be
// used.
//
// The parameters are considered invalid under any of the following conditions:
// - |r| or |p| are zero
// - |p| > (2^30 - 1) / |r|
// - |N| is not a power of two
// - |N| > 2^32
// - |N| > 2^(128 * |r| / 8)
OPENSSL_EXPORT int EVP_PBE_scrypt(const char *password, size_t password_len,
                                  const uint8_t *salt, size_t salt_len,
                                  uint64_t N, uint64_t r, uint64_t p,
                                  size_t max_mem, uint8_t *out_key,
                                  size_t key_len);


// Public key contexts.
//
// |EVP_PKEY_CTX| objects hold the context of an operation (e.g. signing or
// encrypting) that uses a public key.

// EVP_PKEY_CTX_new allocates a fresh |EVP_PKEY_CTX| for use with |pkey|. It
// returns the context or NULL on error.
OPENSSL_EXPORT EVP_PKEY_CTX *EVP_PKEY_CTX_new(EVP_PKEY *pkey, ENGINE *e);

// EVP_PKEY_CTX_new_id allocates a fresh |EVP_PKEY_CTX| for a key of type |id|
// (e.g. |EVP_PKEY_HMAC|). This can be used for key generation where
// |EVP_PKEY_CTX_new| can't be used because there isn't an |EVP_PKEY| to pass
// it. It returns the context or NULL on error.
OPENSSL_EXPORT EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e);

// EVP_PKEY_CTX_free frees |ctx| and the data it owns.
OPENSSL_EXPORT void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx);

// EVP_PKEY_CTX_dup allocates a fresh |EVP_PKEY_CTX| and sets it equal to the
// state of |ctx|. It returns the fresh |EVP_PKEY_CTX| or NULL on error.
OPENSSL_EXPORT EVP_PKEY_CTX *EVP_PKEY_CTX_dup(EVP_PKEY_CTX *ctx);

// EVP_PKEY_CTX_get0_pkey returns the |EVP_PKEY| associated with |ctx|.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_CTX_get0_pkey(EVP_PKEY_CTX *ctx);

// EVP_PKEY_sign_init initialises an |EVP_PKEY_CTX| for a signing operation. It
// should be called before |EVP_PKEY_sign|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_sign_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_sign signs |digest_len| bytes from |digest| using |ctx|. If |sig| is
// NULL, the maximum size of the signature is written to |out_sig_len|.
// Otherwise, |*sig_len| must contain the number of bytes of space available at
// |sig|. If sufficient, the signature will be written to |sig| and |*sig_len|
// updated with the true length. This function will fail for signature
// algorithms like Ed25519 and ML-DSA that do not support signing pre-hashed
// inputs.
//
// WARNING: |digest| must be the output of some hash function on the data to be
// signed. Passing unhashed inputs will not result in a secure signature scheme.
// Use |EVP_DigestSignInit| to sign an unhashed input.
//
// WARNING: Setting |sig| to NULL only gives the maximum size of the
// signature. The actual signature may be smaller.
//
// It returns one on success or zero on error. (Note: this differs from
// OpenSSL, which can also return negative values to indicate an error. )
OPENSSL_EXPORT int EVP_PKEY_sign(EVP_PKEY_CTX *ctx, uint8_t *sig,
                                 size_t *sig_len, const uint8_t *digest,
                                 size_t digest_len);

// EVP_PKEY_verify_init initialises an |EVP_PKEY_CTX| for a signature
// verification operation. It should be called before |EVP_PKEY_verify|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_verify_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_verify verifies that |sig_len| bytes from |sig| are a valid
// signature for |digest|. This function will fail for signature
// algorithms like Ed25519 and ML-DSA that do not support signing pre-hashed
// inputs.
//
// WARNING: |digest| must be the output of some hash function on the data to be
// verified. Passing unhashed inputs will not result in a secure signature
// scheme. Use |EVP_DigestVerifyInit| to verify a signature given the unhashed
// input.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_verify(EVP_PKEY_CTX *ctx, const uint8_t *sig,
                                   size_t sig_len, const uint8_t *digest,
                                   size_t digest_len);

// EVP_PKEY_encrypt_init initialises an |EVP_PKEY_CTX| for an encryption
// operation. It should be called before |EVP_PKEY_encrypt|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_encrypt encrypts |in_len| bytes from |in|. If |out| is NULL, the
// maximum size of the ciphertext is written to |out_len|. Otherwise, |*out_len|
// must contain the number of bytes of space available at |out|. If sufficient,
// the ciphertext will be written to |out| and |*out_len| updated with the true
// length.
//
// WARNING: Setting |out| to NULL only gives the maximum size of the
// ciphertext. The actual ciphertext may be smaller.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx, uint8_t *out,
                                    size_t *out_len, const uint8_t *in,
                                    size_t in_len);

// EVP_PKEY_decrypt_init initialises an |EVP_PKEY_CTX| for a decryption
// operation. It should be called before |EVP_PKEY_decrypt|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_decrypt_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_decrypt decrypts |in_len| bytes from |in|. If |out| is NULL, the
// maximum size of the plaintext is written to |out_len|. Otherwise, |*out_len|
// must contain the number of bytes of space available at |out|. If sufficient,
// the ciphertext will be written to |out| and |*out_len| updated with the true
// length.
//
// WARNING: Setting |out| to NULL only gives the maximum size of the
// plaintext. The actual plaintext may be smaller.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_decrypt(EVP_PKEY_CTX *ctx, uint8_t *out,
                                    size_t *out_len, const uint8_t *in,
                                    size_t in_len);

// EVP_PKEY_verify_recover_init initialises an |EVP_PKEY_CTX| for a public-key
// decryption operation. It should be called before |EVP_PKEY_verify_recover|.
//
// Public-key decryption is a very obscure operation that is only implemented
// by RSA keys. It is effectively a signature verification operation that
// returns the signed message directly. It is almost certainly not what you
// want.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_verify_recover_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_verify_recover decrypts |sig_len| bytes from |sig|. If |out| is
// NULL, the maximum size of the plaintext is written to |out_len|. Otherwise,
// |*out_len| must contain the number of bytes of space available at |out|. If
// sufficient, the ciphertext will be written to |out| and |*out_len| updated
// with the true length.
//
// WARNING: Setting |out| to NULL only gives the maximum size of the
// plaintext. The actual plaintext may be smaller.
//
// See the warning about this operation in |EVP_PKEY_verify_recover_init|. It
// is probably not what you want.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_verify_recover(EVP_PKEY_CTX *ctx, uint8_t *out,
                                           size_t *out_len, const uint8_t *sig,
                                           size_t siglen);

// EVP_PKEY_derive_init initialises an |EVP_PKEY_CTX| for a key derivation
// operation. It should be called before |EVP_PKEY_derive_set_peer| and
// |EVP_PKEY_derive|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_derive_set_peer sets the peer's key to be used for key derivation
// by |ctx| to |peer|. It should be called after |EVP_PKEY_derive_init|. (For
// example, this is used to set the peer's key in (EC)DH.) It returns one on
// success and zero on error.
OPENSSL_EXPORT int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer);

// EVP_PKEY_derive derives a shared key from |ctx|. If |key| is non-NULL then,
// on entry, |out_key_len| must contain the amount of space at |key|. If
// sufficient then the shared key will be written to |key| and |*out_key_len|
// will be set to the length. If |key| is NULL then |out_key_len| will be set to
// the maximum length.
//
// WARNING: Setting |out| to NULL only gives the maximum size of the key. The
// actual key may be smaller.
//
// It returns one on success and zero on error.
OPENSSL_EXPORT int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, uint8_t *key,
                                   size_t *out_key_len);

// EVP_PKEY_keygen_init initialises an |EVP_PKEY_CTX| for a key generation
// operation. It should be called before |EVP_PKEY_keygen|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_keygen_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_keygen performs a key generation operation using the values from
// |ctx|. If |*out_pkey| is non-NULL, it overwrites |*out_pkey| with the
// resulting key. Otherwise, it sets |*out_pkey| to a newly-allocated |EVP_PKEY|
// containing the result. It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY **out_pkey);

// EVP_PKEY_encapsulate is an operation defined for a KEM (Key Encapsulation
// Mechanism). For the KEM specified in |ctx|, the function:
//   1. generates a random value and writes it to |shared_secret|,
//   2. encapsulates the shared secret, producing the ciphertext, by using
//      the public key in |ctx|, and writes the ciphertext to |ciphertext|,
//   3. writes the length of |ciphertext| and |shared_secret| to
//      |ciphertext_len| and |shared_secret_len|.
//
// The function requires that output buffers, |ciphertext| and |shared_secret|,
// be either both NULL or both non-NULL. Otherwise, a failure is returned.
//
// If both |ciphertext| and |shared_secret| are NULL it is assumed that
// the caller is doing a size check: the function will write the size of
// the ciphertext and the shared secret in |ciphertext_len| and
// |shared_secret_len| and return successfully.
//
// If both |ciphertext| and |shared_secret| are not NULL it is assumed that
// the caller is performing the actual operation. The function will check
// additionally if the lengths of the output buffers, |ciphertext_len| and
// |shared_secret_len|, are large enough for the KEM.
//
// NOTE: no allocation is done in the function, the caller is expected to
// provide large enough |ciphertext| and |shared_secret| buffers.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_encapsulate(EVP_PKEY_CTX *ctx          /* IN  */,
                                        uint8_t *ciphertext        /* OUT */,
                                        size_t  *ciphertext_len    /* OUT */,
                                        uint8_t *shared_secret     /* OUT */,
                                        size_t  *shared_secret_len /* OUT */);

// EVP_PKEY_decapsulate is an operation defined for a KEM (Key Encapsulation
// Mechanism). For the KEM specified in |ctx|, the function:
//   1. decapsulates the shared secret from the given |ciphertext| using the
//      secret key configured in |ctx| and writes it to |shared_secret|,
//   2. writes the length of |shared_secret| to |shared_secret_len|.
//
// If the given |shared_secret| is NULL it is assumed that the caller is doing
// a size check: the function will write the size of the shared secret in
// |shared_secret_len| and return successfully.
//
// If |shared_secret| is non-NULL it is assumed that the caller is performing
// the actual operation. The functions will check additionally if the length of
// the output buffer |shared_secret_len| is large enough for the KEM.
//
// NOTE: no allocation is done in the function, the caller is expected to
// provide large enough |shared_secret| buffer.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_decapsulate(EVP_PKEY_CTX *ctx          /* IN  */,
                                        uint8_t *shared_secret     /* OUT */,
                                        size_t  *shared_secret_len /* OUT */,
                                        const uint8_t *ciphertext  /* IN  */,
                                        size_t   ciphertext_len    /* IN  */);

// EVP_PKEY_paramgen_init initialises an |EVP_PKEY_CTX| for a parameter
// generation operation. It should be called before |EVP_PKEY_paramgen|.
//
// It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_paramgen_init(EVP_PKEY_CTX *ctx);

// EVP_PKEY_paramgen performs a parameter generation using the values from
// |ctx|. If |*out_pkey| is non-NULL, it overwrites |*out_pkey| with the
// resulting parameters, but no key. Otherwise, it sets |*out_pkey| to a
// newly-allocated |EVP_PKEY| containing the result. It returns one on success
// or zero on error.
OPENSSL_EXPORT int EVP_PKEY_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY **out_pkey);


// Generic control functions.

// EVP_PKEY_CTX_set_signature_md sets |md| as the digest to be used in a
// signature operation. It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx,
                                                 const EVP_MD *md);

// EVP_PKEY_CTX_get_signature_md sets |*out_md| to the digest to be used in a
// signature operation. It returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx,
                                                 const EVP_MD **out_md);


// RSA specific control functions.

// EVP_PKEY_CTX_set_rsa_padding sets the padding type to use. It should be one
// of the |RSA_*_PADDING| values. Returns one on success or zero on error. By
// default, the padding is |RSA_PKCS1_PADDING|.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int padding);

// EVP_PKEY_CTX_get_rsa_padding sets |*out_padding| to the current padding
// value, which is one of the |RSA_*_PADDING| values. Returns one on success or
// zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx,
                                                int *out_padding);

// EVP_PKEY_CTX_set_rsa_pss_saltlen sets the length of the salt in a PSS-padded
// signature. A value of -1 cause the salt to be the same length as the digest
// in the signature. A value of -2 causes the salt to be the maximum length
// that will fit when signing and recovered from the signature when verifying.
// Otherwise the value gives the size of the salt in bytes.
//
// If unsure, use -1.
//
// Returns one on success or zero on error.
//
// TODO(davidben): The default is currently -2. Switch it to -1.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx,
                                                    int salt_len);

// EVP_PKEY_CTX_get_rsa_pss_saltlen sets |*out_salt_len| to the salt length of
// a PSS-padded signature. See the documentation for
// |EVP_PKEY_CTX_set_rsa_pss_saltlen| for details of the special values that it
// can take.
//
// Returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx,
                                                    int *out_salt_len);

// EVP_PKEY_CTX_set_rsa_keygen_bits sets the size of the desired RSA modulus,
// in bits, for key generation. Returns one on success or zero on
// error.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx,
                                                    int bits);

// EVP_PKEY_CTX_set_rsa_keygen_pubexp sets |e| as the public exponent for key
// generation. Returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx,
                                                      BIGNUM *e);

// EVP_PKEY_CTX_set_rsa_oaep_md sets |md| as the digest used in OAEP padding.
// Returns one on success or zero on error. If unset, the default is SHA-1.
// Callers are recommended to overwrite this default.
//
// TODO(davidben): Remove the default and require callers specify this.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx,
                                                const EVP_MD *md);

// EVP_PKEY_CTX_get_rsa_oaep_md sets |*out_md| to the digest function used in
// OAEP padding. Returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx,
                                                const EVP_MD **out_md);

// EVP_PKEY_CTX_set_rsa_mgf1_md sets |md| as the digest used in MGF1. Returns
// one on success or zero on error.
//
// If unset, the default is the signing hash for |RSA_PKCS1_PSS_PADDING| and the
// OAEP hash for |RSA_PKCS1_OAEP_PADDING|. Callers are recommended to use this
// default and not call this function.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx,
                                                const EVP_MD *md);

// EVP_PKEY_CTX_get_rsa_mgf1_md sets |*out_md| to the digest function used in
// MGF1. Returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx,
                                                const EVP_MD **out_md);

// EVP_PKEY_CTX_set0_rsa_oaep_label sets |label_len| bytes from |label| as the
// label used in OAEP. DANGER: On success, this call takes ownership of |label|
// and will call |OPENSSL_free| on it when |ctx| is destroyed.
//
// Returns one on success or zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx,
                                                    uint8_t *label,
                                                    size_t label_len);

// EVP_PKEY_CTX_get0_rsa_oaep_label sets |*out_label| to point to the internal
// buffer containing the OAEP label (which may be NULL) and returns the length
// of the label or a negative value on error.
//
// WARNING: the return value differs from the usual return value convention.
OPENSSL_EXPORT int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx,
                                                    const uint8_t **out_label);


// EC specific control functions.

// EVP_PKEY_CTX_set_ec_paramgen_curve_nid sets the curve used for
// |EVP_PKEY_keygen| or |EVP_PKEY_paramgen| operations to |nid|. It returns one
// on success and zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx,
                                                          int nid);

// KEM specific functions.

// EVP_PKEY_CTX_kem_set_params sets in |ctx| the parameters associated with the
// KEM defined by the given |nid|. It returns one on success and zero on error.
OPENSSL_EXPORT int EVP_PKEY_CTX_kem_set_params(EVP_PKEY_CTX *ctx, int nid);

// EVP_PKEY_kem_new_raw_public_key generates a new EVP_PKEY object of type
// EVP_PKEY_KEM, initializes the KEM key based on |nid| and populates the
// public key part of the KEM key with the contents of |in|. It returns the
// pointer to the allocated PKEY on sucess and NULL on error.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_kem_new_raw_public_key(
                                    int nid, const uint8_t *in, size_t len);

// EVP_PKEY_kem_new_raw_secret_key generates a new EVP_PKEY object of type
// EVP_PKEY_KEM, initializes the KEM key based on |nid| and populates the
// secret key part of the KEM key with the contents of |in|. It returns the
// pointer to the allocated PKEY on sucess and NULL on error.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_kem_new_raw_secret_key(
                                    int nid, const uint8_t *in, size_t len);

// EVP_PKEY_kem_new_raw_key generates a new EVP_PKEY object of type
// EVP_PKEY_KEM, initializes the KEM key based on |nid| and populates the
// public and secret key parts of the KEM key with the contents of |in_public|
// and |in_secret|. It returns the pointer to the allocated PKEY on sucess and
// NULL on error.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_kem_new_raw_key(int nid,
                                                  const uint8_t *in_public,
                                                  size_t len_public,
                                                  const uint8_t *in_secret,
                                                  size_t len_secret);

// EVP_PKEY_kem_check_key validates that the public key in |key| corresponds
// to the secret key in |key|.
OPENSSL_EXPORT int EVP_PKEY_kem_check_key(EVP_PKEY *key);


// Diffie-Hellman-specific control functions.

// EVP_PKEY_CTX_set_dh_pad configures configures whether |ctx|, which must be an
// |EVP_PKEY_derive| operation, configures the handling of leading zeros in the
// Diffie-Hellman shared secret. If |pad| is zero, leading zeros are removed
// from the secret. If |pad| is non-zero, the fixed-width shared secret is used
// unmodified, as in PKCS #3. If this function is not called, the default is to
// remove leading zeros.
//
// WARNING: The behavior when |pad| is zero leaks information about the shared
// secret. This may result in side channel attacks such as
// https://raccoon-attack.com/, particularly when the same private key is used
// for multiple operations.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad);


// ASN1 functions

// EVP_PKEY_asn1_get_count returns the number of available
// |EVP_PKEY_ASN1_METHOD| structures.
OPENSSL_EXPORT int EVP_PKEY_asn1_get_count(void);

// EVP_PKEY_asn1_get0 returns a pointer to an EVP_PKEY_ASN1_METHOD structure.
// |idx| is the index value, which must be a non-negative value smaller than
// the return value of |EVP_PKEY_asn1_get_count|.
OPENSSL_EXPORT const EVP_PKEY_ASN1_METHOD *EVP_PKEY_asn1_get0(int idx);

// EVP_PKEY_asn1_find finds an |EVP_PKEY_ASN1_METHOD| structure for the given
// key |type|, e.g. |EVP_PKEY_EC| or |EVP_PKEY_RSA|. |pe| is ignored.
OPENSSL_EXPORT const EVP_PKEY_ASN1_METHOD *EVP_PKEY_asn1_find(ENGINE **_pe,
                                                              int type);

// EVP_PKEY_asn1_find_str finds an |EVP_PKEY_ASN1_METHOD| structure by name.
// |pe| is ignored.
// |name| is the name of the key type to find, e.g, "RSA" or "EC".
// |len| is the length of the name.
OPENSSL_EXPORT const EVP_PKEY_ASN1_METHOD *EVP_PKEY_asn1_find_str(
    ENGINE **_pe, const char *name, int len);

// EVP_PKEY_asn1_get0_info retrieves information about an |EVP_PKEY_ASN1_METHOD|
// structure.
// |ppkey_id| is a pointer to get the key type identifier.
// |pkey_base_id| is a pointer to get the base key type. Value will be the same
// as |ppkey_id|.
// |ppkey_flags| is not supported.  Value is set to 0 if pointer is not |NULL|.
// |pinfo| is a pointer to get a text description.
// |ppem_str| is a pointer to get the PEM string name.
// |ameth| is a pointer to the EVP_PKEY_ASN1_METHOD structure.
OPENSSL_EXPORT int EVP_PKEY_asn1_get0_info(int *ppkey_id, int *pkey_base_id,
                                           int *ppkey_flags, const char **pinfo,
                                           const char **ppem_str,
                                           const EVP_PKEY_ASN1_METHOD *ameth);


// EVP_PKEY_CTX keygen/paramgen functions.

typedef int EVP_PKEY_gen_cb(EVP_PKEY_CTX *ctx);

// EVP_PKEY_CTX_set_cb sets |cb| as the key or parameter generation callback
// function for |ctx|. The callback function is then translated and used as the
// underlying |BN_GENCB| for |ctx|. Once |cb| is set for |ctx|, any information
// regarding key or parameter generation can be retrieved via
// |EVP_PKEY_CTX_get_keygen_info|.
// This behavior only applies to |EVP_PKEY|s that have calls to |BN_GENCB|
// available, which is only |EVP_PKEY_RSA|.
//
// TODO: Add support for |EVP_PKEY_DH| once we have param_gen support.
OPENSSL_EXPORT void EVP_PKEY_CTX_set_cb(EVP_PKEY_CTX *ctx, EVP_PKEY_gen_cb *cb);

// EVP_PKEY_CTX_get_keygen_info returns the values associated with the
// |EVP_PKEY_gen_cb|/|BN_GENCB| assigned to |ctx|. This should only be used if
// |EVP_PKEY_CTX_set_cb| has been called. If |idx| is -1, the total number of
// available parameters is returned. Any non-negative value less than the total
// number of available parameters, returns the indexed value in the parameter
// array. We return 0 for any invalid |idx| or key type.
//
// The |idx|s in |ctx->keygen_info| correspond to the following values for
// |BN_GENCB|:
//     1. |ctx->keygen_info[0]| -> |event|
//     2. |ctx->keygen_info[1]| -> |n|
// See documentation for |BN_GENCB| for more details regarding the definition
// of each parameter.
//
// TODO: Add support for |EVP_PKEY_DH| once we have param_gen support.
OPENSSL_EXPORT int EVP_PKEY_CTX_get_keygen_info(EVP_PKEY_CTX *ctx, int idx);

// EVP_PKEY_CTX_set_app_data sets |app_data| for |ctx|.
OPENSSL_EXPORT void EVP_PKEY_CTX_set_app_data(EVP_PKEY_CTX *ctx, void *data);

// EVP_PKEY_CTX_get_app_data returns |ctx|'s |app_data|.
OPENSSL_EXPORT void *EVP_PKEY_CTX_get_app_data(EVP_PKEY_CTX *ctx);


// Deprecated functions.

// EVP_PKEY_RSA2 was historically an alternate form for RSA public keys (OID
// 2.5.8.1.1), but is no longer accepted.
#define EVP_PKEY_RSA2 NID_rsa

// EVP_PKEY_X448 is defined for OpenSSL compatibility, but we do not support
// X448 and attempts to create keys will fail.
#define EVP_PKEY_X448 NID_X448

// EVP_PKEY_ED448 is defined for OpenSSL compatibility, but we do not support
// Ed448 and attempts to create keys will fail.
#define EVP_PKEY_ED448 NID_ED448

// EVP_MD_get_pkey_type returns the NID of the public key signing algorithm
// associated with |md| and RSA. This does not return all potential signing
// algorithms that could work with |md| and should not be used.
OPENSSL_EXPORT int EVP_MD_get_pkey_type(const EVP_MD *md);

// EVP_MD_pkey_type calls |EVP_MD_get_pkey_type|.
OPENSSL_EXPORT int EVP_MD_pkey_type(const EVP_MD *md);

OPENSSL_EXPORT void EVP_CIPHER_do_all_sorted(
    void (*callback)(const EVP_CIPHER *cipher, const char *name,
                     const char *unused, void *arg),
    void *arg);

OPENSSL_EXPORT void EVP_MD_do_all_sorted(void (*callback)(const EVP_MD *cipher,
                                                          const char *name,
                                                          const char *unused,
                                                          void *arg),
                                         void *arg);

// EVP_MD_do_all is the same as |EVP_MD_do_all_sorted|. We include both for
// compatibility reasons.
OPENSSL_EXPORT void EVP_MD_do_all(void (*callback)(const EVP_MD *cipher,
                                                   const char *name,
                                                   const char *unused,
                                                   void *arg),
                                         void *arg);


// i2d_PrivateKey marshals a private key from |key| to type-specific format, as
// described in |i2d_SAMPLE|.
//
// RSA keys are serialized as a DER-encoded RSAPublicKey (RFC 8017) structure.
// EC keys are serialized as a DER-encoded ECPrivateKey (RFC 5915) structure.
//
// Use |RSA_marshal_private_key| or |EC_KEY_marshal_private_key| instead.
OPENSSL_EXPORT int i2d_PrivateKey(const EVP_PKEY *key, uint8_t **outp);

// i2d_PublicKey marshals a public key from |key| to a type-specific format, as
// described in |i2d_SAMPLE|.
//
// RSA keys are serialized as a DER-encoded RSAPublicKey (RFC 8017) structure.
// EC keys are serialized as an EC point per SEC 1.
//
// Use |RSA_marshal_public_key| or |EC_POINT_point2cbb| instead.
OPENSSL_EXPORT int i2d_PublicKey(const EVP_PKEY *key, uint8_t **outp);

// d2i_PrivateKey parses a DER-encoded private key from |len| bytes at |*inp|,
// as described in |d2i_SAMPLE|. The private key must have type |type|,
// otherwise it will be rejected.
//
// This function tries to detect one of several formats. Instead, use
// |EVP_parse_private_key| for a PrivateKeyInfo, |RSA_parse_private_key| for an
// RSAPrivateKey, and |EC_parse_private_key| for an ECPrivateKey.
OPENSSL_EXPORT EVP_PKEY *d2i_PrivateKey(int type, EVP_PKEY **out,
                                        const uint8_t **inp, long len);

// d2i_AutoPrivateKey acts the same as |d2i_PrivateKey|, but detects the type
// of the private key.
//
// This function tries to detect one of several formats. Instead, use
// |EVP_parse_private_key| for a PrivateKeyInfo, |RSA_parse_private_key| for an
// RSAPrivateKey, and |EC_parse_private_key| for an ECPrivateKey.
OPENSSL_EXPORT EVP_PKEY *d2i_AutoPrivateKey(EVP_PKEY **out, const uint8_t **inp,
                                            long len);

// d2i_PublicKey parses a public key from |len| bytes at |*inp| in a type-
// specific format specified by |type|, as described in |d2i_SAMPLE|.
//
// The only supported value for |type| is |EVP_PKEY_RSA|, which parses a
// DER-encoded RSAPublicKey (RFC 8017) structure. Parsing EC keys is not
// supported by this function.
//
// Use |RSA_parse_public_key| instead.
OPENSSL_EXPORT EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **out,
                                       const uint8_t **inp, long len);

// EVP_PKEY_CTX_set_ec_param_enc returns one if |encoding| is
// |OPENSSL_EC_NAMED_CURVE| or zero with an error otherwise.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx,
                                                 int encoding);

// EVP_PKEY_set1_tls_encodedpoint replaces |pkey| with a public key encoded by
// |in|. It returns one on success and zero on error. |len| is the size of |in|.
// Any value of |len| below 1 is interpreted as an invalid input and will result
// in an error.
//
// This function only works on X25519 |EVP_PKEY_X25519| and EC |EVP_PKEY_EC| key
// types. The supported curve for |EVP_PKEY_X25519| is Curve25519. The supported
// curves for |EVP_PKEY_EC| are: NID_secp224r1, NID_X9_62_prime256v1,
// NID_secp384r1, NID_secp521r1
//
// For the EC key type, the EC point representation must be in
// uncompressed form.
OPENSSL_EXPORT int EVP_PKEY_set1_tls_encodedpoint(EVP_PKEY *pkey,
                                                  const uint8_t *in,
                                                  size_t len);

// EVP_PKEY_get1_tls_encodedpoint sets |*out_ptr| to a newly-allocated buffer
// containing the raw encoded public key for |pkey|. The caller must call
// |OPENSSL_free| to release this buffer on success. The function returns the
// length of the buffer on success and zero on error.
//
// This function only works on X25519 |EVP_PKEY_X25519| and EC |EVP_PKEY_EC| key
// types. The supported curve for |EVP_PKEY_X25519| is Curve25519. The supported
// curves for |EVP_PKEY_EC| are: NID_secp224r1, NID_X9_62_prime256v1,
// NID_secp384r1, NID_secp521r1
//
// For the EC key type, the EC point representation must be in
// uncompressed form.
OPENSSL_EXPORT size_t EVP_PKEY_get1_tls_encodedpoint(const EVP_PKEY *pkey,
                                                     uint8_t **out_ptr);

// EVP_PKEY_base_id calls |EVP_PKEY_id|.
OPENSSL_EXPORT int EVP_PKEY_base_id(const EVP_PKEY *pkey);

// EVP_PKEY_CTX_set_rsa_pss_keygen_md returns 0.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_pss_keygen_md(EVP_PKEY_CTX *ctx,
                                                      const EVP_MD *md);

// EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen returns 0.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen(EVP_PKEY_CTX *ctx,
                                                           int salt_len);

// EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md returns 0.
OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md(EVP_PKEY_CTX *ctx,
                                                           const EVP_MD *md);

// i2d_PUBKEY marshals |pkey| as a DER-encoded SubjectPublicKeyInfo, as
// described in |i2d_SAMPLE|.
//
// Use |EVP_marshal_public_key| instead.
OPENSSL_EXPORT int i2d_PUBKEY(const EVP_PKEY *pkey, uint8_t **outp);

// d2i_PUBKEY parses a DER-encoded SubjectPublicKeyInfo from |len| bytes at
// |*inp|, as described in |d2i_SAMPLE|.
//
// Use |EVP_parse_public_key| instead.
OPENSSL_EXPORT EVP_PKEY *d2i_PUBKEY(EVP_PKEY **out, const uint8_t **inp,
                                    long len);

// i2d_RSA_PUBKEY marshals |rsa| as a DER-encoded SubjectPublicKeyInfo
// structure, as described in |i2d_SAMPLE|.
//
// Use |EVP_marshal_public_key| instead.
OPENSSL_EXPORT int i2d_RSA_PUBKEY(const RSA *rsa, uint8_t **outp);

// d2i_RSA_PUBKEY parses an RSA public key as a DER-encoded SubjectPublicKeyInfo
// from |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
// SubjectPublicKeyInfo structures containing other key types are rejected.
//
// Use |EVP_parse_public_key| instead.
OPENSSL_EXPORT RSA *d2i_RSA_PUBKEY(RSA **out, const uint8_t **inp, long len);

// i2d_DSA_PUBKEY marshals |dsa| as a DER-encoded SubjectPublicKeyInfo, as
// described in |i2d_SAMPLE|.
//
// Use |EVP_marshal_public_key| instead.
OPENSSL_EXPORT int i2d_DSA_PUBKEY(const DSA *dsa, uint8_t **outp);

// d2i_DSA_PUBKEY parses a DSA public key as a DER-encoded SubjectPublicKeyInfo
// from |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
// SubjectPublicKeyInfo structures containing other key types are rejected.
//
// Use |EVP_parse_public_key| instead.
OPENSSL_EXPORT DSA *d2i_DSA_PUBKEY(DSA **out, const uint8_t **inp, long len);

// i2d_EC_PUBKEY marshals |ec_key| as a DER-encoded SubjectPublicKeyInfo, as
// described in |i2d_SAMPLE|.
//
// Use |EVP_marshal_public_key| instead.
OPENSSL_EXPORT int i2d_EC_PUBKEY(const EC_KEY *ec_key, uint8_t **outp);

// d2i_EC_PUBKEY parses an EC public key as a DER-encoded SubjectPublicKeyInfo
// from |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
// SubjectPublicKeyInfo structures containing other key types are rejected.
//
// Use |EVP_parse_public_key| instead.
OPENSSL_EXPORT EC_KEY *d2i_EC_PUBKEY(EC_KEY **out, const uint8_t **inp,
                                     long len);

// EVP_PKEY_assign sets the underlying key of |pkey| to |key|, which must be of
// the given type. If successful, it returns one. If the |type| argument
// is one of |EVP_PKEY_RSA|, |EVP_PKEY_DSA|, or |EVP_PKEY_EC| values it calls
// the corresponding |EVP_PKEY_assign_*| functions (which should be used instead).
// Otherwise, if |type| cannot be set via |EVP_PKEY_set_type| or if the key
// is NULL, it returns zero.
OPENSSL_EXPORT int EVP_PKEY_assign(EVP_PKEY *pkey, int type, void *key);

// EVP_PKEY_new_mac_key is deprecated. It allocates a fresh |EVP_PKEY| of
// |type|. Only |EVP_PKEY_HMAC| is supported. |mac_key| is used as the HMAC key,
// NULL |mac_key| will result in a complete zero-key being used, but in that
// case, the length must be zero. This returns the fresh |EVP_PKEY|, or NULL on
// error.
//
// NOTE: Use |HMAC_CTX| directly instead.
OPENSSL_EXPORT EVP_PKEY *EVP_PKEY_new_mac_key(int type, ENGINE *engine,
                                              const uint8_t *mac_key,
                                              size_t mac_key_len);

// EVP_PKEY_get0 returns the consumed key. The type of value returned will be
// one of the following, depending on the type of the |EVP_PKEY|:
// |DH|, |DSA|, |EC_KEY|, or |RSA|.
//
// This function is provided only for compatibility with OpenSSL.
// Prefer the use the typed |EVP_PKEY_get0_*| functions instead.
OPENSSL_EXPORT OPENSSL_DEPRECATED void *EVP_PKEY_get0(const EVP_PKEY *pkey);

// General No-op Functions [Deprecated].

// OpenSSL_add_all_algorithms does nothing. This has been deprecated since
// OpenSSL 1.1.0.
//
// TODO (CryptoAlg-2398): Add |OPENSSL_DEPRECATED|. nginx defines -Werror and
// depends on this.
OPENSSL_EXPORT void OpenSSL_add_all_algorithms(void);

// OPENSSL_add_all_algorithms_conf does nothing. This has been deprecated since
// OpenSSL 1.1.0.
OPENSSL_EXPORT OPENSSL_DEPRECATED void OPENSSL_add_all_algorithms_conf(void);

// OpenSSL_add_all_ciphers does nothing. This has been deprecated since OpenSSL
// 1.1.0.
OPENSSL_EXPORT OPENSSL_DEPRECATED void OpenSSL_add_all_ciphers(void);

// OpenSSL_add_all_digests does nothing. This has been deprecated since OpenSSL
// 1.1.0.
//
// TODO (CryptoAlg-2398): Add |OPENSSL_DEPRECATED|. tpm2-tss defines -Werror and
// depends on this.
OPENSSL_EXPORT void OpenSSL_add_all_digests(void);

// EVP_cleanup does nothing. This has been deprecated since OpenSSL 1.1.0.
OPENSSL_EXPORT OPENSSL_DEPRECATED void EVP_cleanup(void);


// EVP_PKEY_DSA No-ops [Deprecated].
//
// |EVP_PKEY_DSA| is deprecated. It is currently still possible to parse DER
// into a DSA |EVP_PKEY|, but signing or verifying with those objects will not
// work.

#define EVP_PKEY_DSA NID_dsa

// EVP_PKEY_CTX_set_dsa_paramgen_bits returns zero.
OPENSSL_EXPORT OPENSSL_DEPRECATED int EVP_PKEY_CTX_set_dsa_paramgen_bits(
    EVP_PKEY_CTX *ctx, int nbits);

// EVP_PKEY_CTX_set_dsa_paramgen_q_bits returns zero.
OPENSSL_EXPORT OPENSSL_DEPRECATED int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(
    EVP_PKEY_CTX *ctx, int qbits);


// EVP_PKEY_CTX_ctrl_str

// EVP_PKEY_CTX_ctrl_str sets a parameter on |ctx| of type |type| to |value|.
// This function is deprecated and should not be used in new code.
//
// WARNING: This function is difficult to use correctly. New code should use
// the EVP_PKEY_CTX_set1_* or EVP_PKEY_CTX_set_* functions instead.
//
// |ctx| is the context to operate on.
// |type| is the parameter type as a string.
// |value| is the value to set.
//
// It returns 1 for success and 0 or a negative value for failure.
OPENSSL_EXPORT OPENSSL_DEPRECATED int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
                              const char *value);


// Preprocessor compatibility section (hidden).
//
// Historically, a number of APIs were implemented in OpenSSL as macros and
// constants to 'ctrl' functions. To avoid breaking #ifdefs in consumers, this
// section defines a number of legacy macros.

// |BORINGSSL_PREFIX| already makes each of these symbols into macros, so there
// is no need to define conflicting macros.
#if !defined(BORINGSSL_PREFIX)
#define EVP_PKEY_CTX_set_rsa_oaep_md EVP_PKEY_CTX_set_rsa_oaep_md
#define EVP_PKEY_CTX_set0_rsa_oaep_label EVP_PKEY_CTX_set0_rsa_oaep_label
#define EVP_MD_name EVP_MD_name
#define EVP_MD_pkey_type EVP_MD_pkey_type
#endif


// Nodejs compatibility section (hidden).
//
// These defines exist for node.js, with the hope that we can eliminate the
// need for them over time.

#define EVPerr(function, reason) \
  ERR_put_error(ERR_LIB_EVP, 0, reason, __FILE__, __LINE__)


#if defined(__cplusplus)
}  // extern C

extern "C++" {
BSSL_NAMESPACE_BEGIN

BORINGSSL_MAKE_DELETER(EVP_PKEY, EVP_PKEY_free)
BORINGSSL_MAKE_UP_REF(EVP_PKEY, EVP_PKEY_up_ref)
BORINGSSL_MAKE_DELETER(EVP_PKEY_CTX, EVP_PKEY_CTX_free)

BSSL_NAMESPACE_END

}  // extern C++

#endif

#endif  // OPENSSL_HEADER_EVP_H