text: /* 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_grpc/base.h>
  
  #include <openssl_grpc/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_grpc/aead.h>
  #include <openssl_grpc/base64.h>
  #include <openssl_grpc/cipher.h>
  #include <openssl_grpc/digest.h>
  #include <openssl_grpc/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.
  //
  // 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 expects a pre-hashed input and will fail for signature
  // algorithms which do not support this. 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 expects a pre-hashed input and will fail for signature
  // algorithms which do not support this. 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.
  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.
  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.
  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.
  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
  
  // 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);
  
  
  // 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)
  #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
  
  #define EVP_R_BUFFER_TOO_SMALL 100
  #define EVP_R_COMMAND_NOT_SUPPORTED 101
  #define EVP_R_DECODE_ERROR 102
  #define EVP_R_DIFFERENT_KEY_TYPES 103
  #define EVP_R_DIFFERENT_PARAMETERS 104
  #define EVP_R_ENCODE_ERROR 105
  #define EVP_R_EXPECTING_AN_EC_KEY_KEY 106
  #define EVP_R_EXPECTING_AN_RSA_KEY 107
  #define EVP_R_EXPECTING_A_DSA_KEY 108
  #define EVP_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE 109
  #define EVP_R_INVALID_DIGEST_LENGTH 110
  #define EVP_R_INVALID_DIGEST_TYPE 111
  #define EVP_R_INVALID_KEYBITS 112
  #define EVP_R_INVALID_MGF1_MD 113
  #define EVP_R_INVALID_OPERATION 114
  #define EVP_R_INVALID_PADDING_MODE 115
  #define EVP_R_INVALID_PSS_SALTLEN 116
  #define EVP_R_KEYS_NOT_SET 117
  #define EVP_R_MISSING_PARAMETERS 118
  #define EVP_R_NO_DEFAULT_DIGEST 119
  #define EVP_R_NO_KEY_SET 120
  #define EVP_R_NO_MDC2_SUPPORT 121
  #define EVP_R_NO_NID_FOR_CURVE 122
  #define EVP_R_NO_OPERATION_SET 123
  #define EVP_R_NO_PARAMETERS_SET 124
  #define EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE 125
  #define EVP_R_OPERATON_NOT_INITIALIZED 126
  #define EVP_R_UNKNOWN_PUBLIC_KEY_TYPE 127
  #define EVP_R_UNSUPPORTED_ALGORITHM 128
  #define EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE 129
  #define EVP_R_NOT_A_PRIVATE_KEY 130
  #define EVP_R_INVALID_SIGNATURE 131
  #define EVP_R_MEMORY_LIMIT_EXCEEDED 132
  #define EVP_R_INVALID_PARAMETERS 133
  #define EVP_R_INVALID_PEER_KEY 134
  #define EVP_R_NOT_XOF_OR_INVALID_LENGTH 135
  
  #endif  // OPENSSL_HEADER_EVP_H
  