/* 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>
#include <openssl/thread.h>

// OpenSSL included digest and cipher functions in this header so we include
// them for users that still expect that.
//
// TODO(fork): clean up callers so that they include what they use.
#include <openssl/aead.h>
#include <openssl/base64.h>
#include <openssl/cipher.h>
#include <openssl/digest.h>
#include <openssl/nid.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.
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.
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);


// 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);

#define EVP_PKEY_NONE NID_undef
#define EVP_PKEY_RSA NID_rsaEncryption
#define EVP_PKEY_RSA_PSS NID_rsassaPss
#define EVP_PKEY_DSA NID_dsa
#define EVP_PKEY_EC NID_X9_62_id_ecPublicKey
#define EVP_PKEY_ED25519 NID_ED25519
#define EVP_PKEY_X25519 NID_X25519

// EVP_PKEY_assign sets the underlying key of |pkey| to |key|, which must be of
// the given type. It returns one if successful or zero if the |type| argument
// is not one of the |EVP_PKEY_*| values or if |key| is NULL.
OPENSSL_EXPORT int EVP_PKEY_assign(EVP_PKEY *pkey, int type, void *key);

// 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);


// Raw keys
//
// Some keys types support a "raw" serialization. Currently the only supported
// raw format is Ed25519, where the public key and private key formats are those
// specified in RFC 8032. Note the RFC 8032 private key format is the 32-byte
// prefix of |ED25519_sign|'s 64-byte private key.

// EVP_PKEY_new_raw_private_key returns a newly allocated |EVP_PKEY| wrapping a
// private key of the specified type. It returns one on success and zero 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 one on success and zero 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, |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, |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.

// 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.
OPENSSL_EXPORT int PKCS5_PBKDF2_HMAC(const char *password, size_t password_len,
                                     const uint8_t *salt, size_t salt_len,
                                     unsigned 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,
                                          unsigned 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 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 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 between the two keys configured in
// |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_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);


// Deprecated functions.

// EVP_PKEY_DH is defined for compatibility, but it is impossible to create an
// |EVP_PKEY| of that type.
#define EVP_PKEY_DH NID_dhKeyAgreement

// 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_PKEY_get0 returns NULL. This function is provided for compatibility with
// OpenSSL but does not return anything. Use the typed |EVP_PKEY_get0_*|
// functions instead.
OPENSSL_EXPORT void *EVP_PKEY_get0(const EVP_PKEY *pkey);

// OpenSSL_add_all_algorithms does nothing.
OPENSSL_EXPORT void OpenSSL_add_all_algorithms(void);

// OPENSSL_add_all_algorithms_conf does nothing.
OPENSSL_EXPORT void OPENSSL_add_all_algorithms_conf(void);

// OpenSSL_add_all_ciphers does nothing.
OPENSSL_EXPORT void OpenSSL_add_all_ciphers(void);

// OpenSSL_add_all_digests does nothing.
OPENSSL_EXPORT void OpenSSL_add_all_digests(void);

// EVP_cleanup does nothing.
OPENSSL_EXPORT void EVP_cleanup(void);

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);

// i2d_PrivateKey marshals a private key from |key| to an ASN.1, DER
// structure. If |outp| is not NULL then the result is written to |*outp| and
// |*outp| is advanced just past the output. It returns the number of bytes in
// the result, whether written or not, or a negative value on error.
//
// RSA keys are serialized as a DER-encoded RSAPublicKey (RFC 3447) 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.
// If |outp| is not NULL then the result is written to |*outp| and
// |*outp| is advanced just past the output. It returns the number of bytes in
// the result, whether written or not, or a negative value on error.
//
// RSA keys are serialized as a DER-encoded RSAPublicKey (RFC 3447) 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 an ASN.1, DER-encoded, private key from |len| bytes at
// |*inp|. If |out| is not NULL then, on exit, a pointer to the result is in
// |*out|. Note that, even if |*out| is already non-NULL on entry, it will not
// be written to. Rather, a fresh |EVP_PKEY| is allocated and the previous one
// is freed. On successful exit, |*inp| is advanced past the DER structure. It
// returns the result or NULL on error.
//
// 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 parse a public key from |len| bytes at |*inp| in a type-
// specific format specified by |type|. If |out| is not NULL then, on exit, a
// pointer to the result is in |*out|. Note that, even if |*out| is already non-
// NULL on entry, it will not be written to. Rather, a fresh |EVP_PKEY| is
// allocated and the previous one is freed. On successful exit, |*inp| is
// advanced past the decoded key. It returns the result or NULL on error.
//
// RSA keys are parsed as a DER-encoded RSAPublicKey (RFC 3447) 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_get0_DH returns NULL.
OPENSSL_EXPORT DH *EVP_PKEY_get0_DH(const EVP_PKEY *pkey);

// EVP_PKEY_get1_DH returns NULL.
OPENSSL_EXPORT DH *EVP_PKEY_get1_DH(const EVP_PKEY *pkey);

// 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.
//
// This function only works on X25519 keys.
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. The function returns the length of the
// buffer on success and zero on error.
//
// This function only works on X25519 keys.
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 a public key from |pkey| as a DER-encoded
// SubjectPublicKeyInfo. If |outp| is not NULL, the result is written to |*outp|
// and |*outp| is advanced just past the output. It returns the number of bytes
// in the result, whether written or not, or a negative value on error.
//
// 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|. It returns a newly-allocated result, or NULL on error. On success,
// |*inp| is advanced past the DER structure. If |out| is not NULL, it also
// frees any existing object pointed by |*out| and writes the result.
//
// 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. If
// |outp| is not NULL, the result is written to |*outp| and
// |*outp| is advanced just past the output. It returns the number of bytes in
// the result, whether written or not, or a negative value on error.
//
// 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|. It returns a newly-allocated result, or NULL on
// error. On success, |*inp| is advanced past the DER structure. If |out| is not
// NULL, it also frees any existing object pointed by |*out| and writes the
// result.
//
// 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. If
// |outp| is not NULL, the result is written to |*outp| and |*outp| is advanced
// just past the output. It returns the number of bytes in the result, whether
// written or not, or a negative value on error.
//
// 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|. It returns a newly-allocated result, or NULL on
// error. On success, |*inp| is advanced past the DER structure. If |out| is not
// NULL, it also frees any existing object pointed by |*out| and writes the
// result.
//
// 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. If
// |outp| is not NULL, the result is written to |*outp| and |*outp| is advanced
// just past the output. It returns the number of bytes in the result, whether
// written or not, or a negative value on error.
//
// 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|. It returns a newly-allocated result, or NULL on
// error. On success, |*inp| is advanced past the DER structure. If |out| is not
// NULL, it also frees any existing object pointed by |*out| and writes the
// result.
//
// Use |EVP_parse_public_key| instead.
OPENSSL_EXPORT EC_KEY *d2i_EC_PUBKEY(EC_KEY **out, const uint8_t **inp,
                                     long len);


// 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
#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__)


// Private structures.

struct evp_pkey_st {
  CRYPTO_refcount_t references;

  // type contains one of the EVP_PKEY_* values or NID_undef and determines
  // which element (if any) of the |pkey| union is valid.
  int type;

  union {
    void *ptr;
    RSA *rsa;
    DSA *dsa;
    DH *dh;
    EC_KEY *ec;
  } pkey;

  // ameth contains a pointer to a method table that contains many ASN.1
  // methods for the key type.
  const EVP_PKEY_ASN1_METHOD *ameth;
} /* EVP_PKEY */;


#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