gnunet-android

bn.h (44476B)

---

 // Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
 // Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef OPENSSL_HEADER_BN_H
 #define OPENSSL_HEADER_BN_H
 
 #include <openssl/base.h>   // IWYU pragma: export
 
 #include <inttypes.h>  // for PRIu64 and friends
 #include <stdio.h>  // for FILE*
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
 
 // BN provides support for working with arbitrary sized integers. For example,
 // although the largest integer supported by the compiler might be 64 bits, BN
 // will allow you to work with much larger numbers.
 //
 // This library is developed for use inside BoringSSL, and uses implementation
 // strategies that may not be ideal for other applications. Non-cryptographic
 // uses should use a more general-purpose integer library, especially if
 // performance-sensitive.
 //
 // Many functions in BN scale quadratically or higher in the bit length of their
 // input. Callers at this layer are assumed to have capped input sizes within
 // their performance tolerances.
 
 
 // BN_ULONG is the native word size when working with big integers.
 //
 // Note: on some platforms, inttypes.h does not define print format macros in
 // C++ unless |__STDC_FORMAT_MACROS| defined. This is due to text in C99 which
 // was never adopted in any C++ standard and explicitly overruled in C++11. As
 // this is a public header, bn.h does not define |__STDC_FORMAT_MACROS| itself.
 // Projects which use |BN_*_FMT*| with outdated C headers may need to define it
 // externally.
 #if defined(OPENSSL_64_BIT)
 typedef uint64_t BN_ULONG;
 #define BN_BITS2 64
 #define BN_DEC_FMT1 "%" PRIu64
 #define BN_HEX_FMT1 "%" PRIx64
 #define BN_HEX_FMT2 "%016" PRIx64
 #elif defined(OPENSSL_32_BIT)
 typedef uint32_t BN_ULONG;
 #define BN_BITS2 32
 #define BN_DEC_FMT1 "%" PRIu32
 #define BN_HEX_FMT1 "%" PRIx32
 #define BN_HEX_FMT2 "%08" PRIx32
 #else
 #error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
 #endif
 
 
 // Allocation and freeing.
 
 // BN_new creates a new, allocated BIGNUM and initialises it.
 OPENSSL_EXPORT BIGNUM *BN_new(void);
 
 // BN_init initialises a stack allocated |BIGNUM|.
 OPENSSL_EXPORT void BN_init(BIGNUM *bn);
 
 // BN_free frees the data referenced by |bn| and, if |bn| was originally
 // allocated on the heap, frees |bn| also.
 OPENSSL_EXPORT void BN_free(BIGNUM *bn);
 
 // BN_clear_free erases and frees the data referenced by |bn| and, if |bn| was
 // originally allocated on the heap, frees |bn| also.
 OPENSSL_EXPORT void BN_clear_free(BIGNUM *bn);
 
 // BN_dup allocates a new BIGNUM and sets it equal to |src|. It returns the
 // allocated BIGNUM on success or NULL otherwise.
 OPENSSL_EXPORT BIGNUM *BN_dup(const BIGNUM *src);
 
 // BN_copy sets |dest| equal to |src| and returns |dest| or NULL on allocation
 // failure.
 OPENSSL_EXPORT BIGNUM *BN_copy(BIGNUM *dest, const BIGNUM *src);
 
 // BN_clear sets |bn| to zero and erases the old data.
 OPENSSL_EXPORT void BN_clear(BIGNUM *bn);
 
 // BN_value_one returns a static BIGNUM with value 1.
 OPENSSL_EXPORT const BIGNUM *BN_value_one(void);
 
 
 // Basic functions.
 
 // BN_num_bits returns the minimum number of bits needed to represent the
 // absolute value of |bn|.
 OPENSSL_EXPORT unsigned BN_num_bits(const BIGNUM *bn);
 
 // BN_num_bytes returns the minimum number of bytes needed to represent the
 // absolute value of |bn|.
 //
 // While |size_t| is the preferred type for byte counts, callers can assume that
 // |BIGNUM|s are bounded such that this value, and its corresponding bit count,
 // will always fit in |int|.
 OPENSSL_EXPORT unsigned BN_num_bytes(const BIGNUM *bn);
 
 // BN_zero sets |bn| to zero.
 OPENSSL_EXPORT void BN_zero(BIGNUM *bn);
 
 // BN_one sets |bn| to one. It returns one on success or zero on allocation
 // failure.
 OPENSSL_EXPORT int BN_one(BIGNUM *bn);
 
 // BN_set_word sets |bn| to |value|. It returns one on success or zero on
 // allocation failure.
 OPENSSL_EXPORT int BN_set_word(BIGNUM *bn, BN_ULONG value);
 
 // BN_set_u64 sets |bn| to |value|. It returns one on success or zero on
 // allocation failure.
 OPENSSL_EXPORT int BN_set_u64(BIGNUM *bn, uint64_t value);
 
 // BN_set_negative sets the sign of |bn|.
 OPENSSL_EXPORT void BN_set_negative(BIGNUM *bn, int sign);
 
 // BN_is_negative returns one if |bn| is negative and zero otherwise.
 OPENSSL_EXPORT int BN_is_negative(const BIGNUM *bn);
 
 
 // Conversion functions.
 
 // BN_bin2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
 // a big-endian number, and returns |ret|. If |ret| is NULL then a fresh
 // |BIGNUM| is allocated and returned. It returns NULL on allocation
 // failure.
 OPENSSL_EXPORT BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret);
 
 // BN_bn2bin serialises the absolute value of |in| to |out| as a big-endian
 // integer, which must have |BN_num_bytes| of space available. It returns the
 // number of bytes written. Note this function leaks the magnitude of |in|. If
 // |in| is secret, use |BN_bn2bin_padded| instead.
 OPENSSL_EXPORT size_t BN_bn2bin(const BIGNUM *in, uint8_t *out);
 
 // BN_lebin2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
 // a little-endian number, and returns |ret|. If |ret| is NULL then a fresh
 // |BIGNUM| is allocated and returned. It returns NULL on allocation
 // failure.
 OPENSSL_EXPORT BIGNUM *BN_lebin2bn(const uint8_t *in, size_t len, BIGNUM *ret);
 
 // BN_bn2le_padded serialises the absolute value of |in| to |out| as a
 // little-endian integer, which must have |len| of space available, padding
 // out the remainder of out with zeros. If |len| is smaller than |BN_num_bytes|,
 // the function fails and returns 0. Otherwise, it returns 1.
 OPENSSL_EXPORT int BN_bn2le_padded(uint8_t *out, size_t len, const BIGNUM *in);
 
 // BN_bn2bin_padded serialises the absolute value of |in| to |out| as a
 // big-endian integer. The integer is padded with leading zeros up to size
 // |len|. If |len| is smaller than |BN_num_bytes|, the function fails and
 // returns 0. Otherwise, it returns 1.
 OPENSSL_EXPORT int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in);
 
 // BN_bn2cbb_padded behaves like |BN_bn2bin_padded| but writes to a |CBB|.
 OPENSSL_EXPORT int BN_bn2cbb_padded(CBB *out, size_t len, const BIGNUM *in);
 
 // BN_bn2hex returns an allocated string that contains a NUL-terminated, hex
 // representation of |bn|. If |bn| is negative, the first char in the resulting
 // string will be '-'. Returns NULL on allocation failure.
 OPENSSL_EXPORT char *BN_bn2hex(const BIGNUM *bn);
 
 // BN_hex2bn parses the leading hex number from |in|, which may be proceeded by
 // a '-' to indicate a negative number and may contain trailing, non-hex data.
 // If |outp| is not NULL, it constructs a BIGNUM equal to the hex number and
 // stores it in |*outp|. If |*outp| is NULL then it allocates a new BIGNUM and
 // updates |*outp|. It returns the number of bytes of |in| processed or zero on
 // error.
 OPENSSL_EXPORT int BN_hex2bn(BIGNUM **outp, const char *in);
 
 // BN_bn2dec returns an allocated string that contains a NUL-terminated,
 // decimal representation of |bn|. If |bn| is negative, the first char in the
 // resulting string will be '-'. Returns NULL on allocation failure.
 //
 // Converting an arbitrarily large integer to decimal is quadratic in the bit
 // length of |a|. This function assumes the caller has capped the input within
 // performance tolerances.
 OPENSSL_EXPORT char *BN_bn2dec(const BIGNUM *a);
 
 // BN_dec2bn parses the leading decimal number from |in|, which may be
 // proceeded by a '-' to indicate a negative number and may contain trailing,
 // non-decimal data. If |outp| is not NULL, it constructs a BIGNUM equal to the
 // decimal number and stores it in |*outp|. If |*outp| is NULL then it
 // allocates a new BIGNUM and updates |*outp|. It returns the number of bytes
 // of |in| processed or zero on error.
 //
 // Converting an arbitrarily large integer to decimal is quadratic in the bit
 // length of |a|. This function assumes the caller has capped the input within
 // performance tolerances.
 OPENSSL_EXPORT int BN_dec2bn(BIGNUM **outp, const char *in);
 
 // BN_asc2bn acts like |BN_dec2bn| or |BN_hex2bn| depending on whether |in|
 // begins with "0X" or "0x" (indicating hex) or not (indicating decimal). A
 // leading '-' is still permitted and comes before the optional 0X/0x. It
 // returns one on success or zero on error.
 OPENSSL_EXPORT int BN_asc2bn(BIGNUM **outp, const char *in);
 
 // BN_print writes a hex encoding of |a| to |bio|. It returns one on success
 // and zero on error.
 OPENSSL_EXPORT int BN_print(BIO *bio, const BIGNUM *a);
 
 // BN_print_fp acts like |BIO_print|, but wraps |fp| in a |BIO| first.
 OPENSSL_EXPORT int BN_print_fp(FILE *fp, const BIGNUM *a);
 
 // BN_get_word returns the absolute value of |bn| as a single word. If |bn| is
 // too large to be represented as a single word, the maximum possible value
 // will be returned.
 OPENSSL_EXPORT BN_ULONG BN_get_word(const BIGNUM *bn);
 
 // BN_get_u64 sets |*out| to the absolute value of |bn| as a |uint64_t| and
 // returns one. If |bn| is too large to be represented as a |uint64_t|, it
 // returns zero.
 OPENSSL_EXPORT int BN_get_u64(const BIGNUM *bn, uint64_t *out);
 
 
 // ASN.1 functions.
 
 // BN_parse_asn1_unsigned parses a non-negative DER INTEGER from |cbs| writes
 // the result to |ret|. It returns one on success and zero on failure.
 OPENSSL_EXPORT int BN_parse_asn1_unsigned(CBS *cbs, BIGNUM *ret);
 
 // BN_marshal_asn1 marshals |bn| as a non-negative DER INTEGER and appends the
 // result to |cbb|. It returns one on success and zero on failure.
 OPENSSL_EXPORT int BN_marshal_asn1(CBB *cbb, const BIGNUM *bn);
 
 
 // BIGNUM pools.
 //
 // Certain BIGNUM operations need to use many temporary variables and
 // allocating and freeing them can be quite slow. Thus such operations typically
 // take a |BN_CTX| parameter, which contains a pool of |BIGNUMs|. The |ctx|
 // argument to a public function may be NULL, in which case a local |BN_CTX|
 // will be created just for the lifetime of that call.
 //
 // A function must call |BN_CTX_start| first. Then, |BN_CTX_get| may be called
 // repeatedly to obtain temporary |BIGNUM|s. All |BN_CTX_get| calls must be made
 // before calling any other functions that use the |ctx| as an argument.
 //
 // Finally, |BN_CTX_end| must be called before returning from the function.
 // When |BN_CTX_end| is called, the |BIGNUM| pointers obtained from
 // |BN_CTX_get| become invalid.
 
 // BN_CTX_new returns a new, empty BN_CTX or NULL on allocation failure.
 OPENSSL_EXPORT BN_CTX *BN_CTX_new(void);
 
 // BN_CTX_free frees all BIGNUMs contained in |ctx| and then frees |ctx|
 // itself.
 OPENSSL_EXPORT void BN_CTX_free(BN_CTX *ctx);
 
 // BN_CTX_start "pushes" a new entry onto the |ctx| stack and allows future
 // calls to |BN_CTX_get|.
 OPENSSL_EXPORT void BN_CTX_start(BN_CTX *ctx);
 
 // BN_CTX_get returns a new |BIGNUM|, or NULL on allocation failure. Once
 // |BN_CTX_get| has returned NULL, all future calls will also return NULL until
 // |BN_CTX_end| is called.
 OPENSSL_EXPORT BIGNUM *BN_CTX_get(BN_CTX *ctx);
 
 // BN_CTX_end invalidates all |BIGNUM|s returned from |BN_CTX_get| since the
 // matching |BN_CTX_start| call.
 OPENSSL_EXPORT void BN_CTX_end(BN_CTX *ctx);
 
 
 // Simple arithmetic
 
 // BN_add sets |r| = |a| + |b|, where |r| may be the same pointer as either |a|
 // or |b|. It returns one on success and zero on allocation failure.
 OPENSSL_EXPORT int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
 
 // BN_uadd sets |r| = |a| + |b|, considering only the absolute values of |a| and
 // |b|. |r| may be the same pointer as either |a| or |b|. It returns one on
 // success and zero on allocation failure.
 OPENSSL_EXPORT int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
 
 // BN_add_word adds |w| to |a|. It returns one on success and zero otherwise.
 OPENSSL_EXPORT int BN_add_word(BIGNUM *a, BN_ULONG w);
 
 // BN_sub sets |r| = |a| - |b|, where |r| may be the same pointer as either |a|
 // or |b|. It returns one on success and zero on allocation failure.
 OPENSSL_EXPORT int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
 
 // BN_usub sets |r| = |a| - |b|, considering only the absolute values of |a| and
 // |b|. The result must be non-negative, i.e. |b| <= |a|. |r| may be the same
 // pointer as either |a| or |b|. It returns one on success and zero on error.
 OPENSSL_EXPORT int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
 
 // BN_sub_word subtracts |w| from |a|. It returns one on success and zero on
 // allocation failure.
 OPENSSL_EXPORT int BN_sub_word(BIGNUM *a, BN_ULONG w);
 
 // BN_mul sets |r| = |a| * |b|, where |r| may be the same pointer as |a| or
 // |b|. Returns one on success and zero otherwise.
 OPENSSL_EXPORT int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                           BN_CTX *ctx);
 
 // BN_mul_word sets |bn| = |bn| * |w|. It returns one on success or zero on
 // allocation failure.
 OPENSSL_EXPORT int BN_mul_word(BIGNUM *bn, BN_ULONG w);
 
 // BN_sqr sets |r| = |a|^2 (i.e. squares), where |r| may be the same pointer as
 // |a|. Returns one on success and zero otherwise. This is more efficient than
 // BN_mul(r, a, a, ctx).
 OPENSSL_EXPORT int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx);
 
 // BN_div divides |numerator| by |divisor| and places the result in |quotient|
 // and the remainder in |rem|. Either of |quotient| or |rem| may be NULL, in
 // which case the respective value is not returned. It returns one on success or
 // zero on error. It is an error condition if |divisor| is zero.
 //
 // The outputs will be such that |quotient| * |divisor| + |rem| = |numerator|,
 // with the quotient rounded towards zero. Thus, if |numerator| is negative,
 // |rem| will be zero or negative. If |divisor| is negative, the sign of
 // |quotient| will be flipped to compensate but otherwise rounding will be as if
 // |divisor| were its absolute value.
 OPENSSL_EXPORT int BN_div(BIGNUM *quotient, BIGNUM *rem,
                           const BIGNUM *numerator, const BIGNUM *divisor,
                           BN_CTX *ctx);
 
 // BN_div_word sets |numerator| = |numerator|/|divisor| and returns the
 // remainder or (BN_ULONG)-1 on error.
 OPENSSL_EXPORT BN_ULONG BN_div_word(BIGNUM *numerator, BN_ULONG divisor);
 
 // BN_sqrt sets |*out_sqrt| (which may be the same |BIGNUM| as |in|) to the
 // square root of |in|, using |ctx|. It returns one on success or zero on
 // error. Negative numbers and non-square numbers will result in an error with
 // appropriate errors on the error queue.
 OPENSSL_EXPORT int BN_sqrt(BIGNUM *out_sqrt, const BIGNUM *in, BN_CTX *ctx);
 
 
 // Comparison functions
 
 // BN_cmp returns a value less than, equal to or greater than zero if |a| is
 // less than, equal to or greater than |b|, respectively.
 OPENSSL_EXPORT int BN_cmp(const BIGNUM *a, const BIGNUM *b);
 
 // BN_cmp_word is like |BN_cmp| except it takes its second argument as a
 // |BN_ULONG| instead of a |BIGNUM|.
 OPENSSL_EXPORT int BN_cmp_word(const BIGNUM *a, BN_ULONG b);
 
 // BN_ucmp returns a value less than, equal to or greater than zero if the
 // absolute value of |a| is less than, equal to or greater than the absolute
 // value of |b|, respectively.
 OPENSSL_EXPORT int BN_ucmp(const BIGNUM *a, const BIGNUM *b);
 
 // BN_equal_consttime returns one if |a| is equal to |b|, and zero otherwise.
 // It takes an amount of time dependent on the sizes of |a| and |b|, but
 // independent of the contents (including the signs) of |a| and |b|.
 OPENSSL_EXPORT int BN_equal_consttime(const BIGNUM *a, const BIGNUM *b);
 
 // BN_abs_is_word returns one if the absolute value of |bn| equals |w| and zero
 // otherwise.
 OPENSSL_EXPORT int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w);
 
 // BN_is_zero returns one if |bn| is zero and zero otherwise.
 OPENSSL_EXPORT int BN_is_zero(const BIGNUM *bn);
 
 // BN_is_one returns one if |bn| equals one and zero otherwise.
 OPENSSL_EXPORT int BN_is_one(const BIGNUM *bn);
 
 // BN_is_word returns one if |bn| is exactly |w| and zero otherwise.
 OPENSSL_EXPORT int BN_is_word(const BIGNUM *bn, BN_ULONG w);
 
 // BN_is_odd returns one if |bn| is odd and zero otherwise.
 OPENSSL_EXPORT int BN_is_odd(const BIGNUM *bn);
 
 // BN_is_pow2 returns 1 if |a| is a power of two, and 0 otherwise.
 OPENSSL_EXPORT int BN_is_pow2(const BIGNUM *a);
 
 
 // Bitwise operations.
 
 // BN_lshift sets |r| equal to |a| << n. The |a| and |r| arguments may be the
 // same |BIGNUM|. It returns one on success and zero on allocation failure.
 OPENSSL_EXPORT int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
 
 // BN_lshift1 sets |r| equal to |a| << 1, where |r| and |a| may be the same
 // pointer. It returns one on success and zero on allocation failure.
 OPENSSL_EXPORT int BN_lshift1(BIGNUM *r, const BIGNUM *a);
 
 // BN_rshift sets |r| equal to |a| >> n, where |r| and |a| may be the same
 // pointer. It returns one on success and zero on allocation failure.
 OPENSSL_EXPORT int BN_rshift(BIGNUM *r, const BIGNUM *a, int n);
 
 // BN_rshift1 sets |r| equal to |a| >> 1, where |r| and |a| may be the same
 // pointer. It returns one on success and zero on allocation failure.
 OPENSSL_EXPORT int BN_rshift1(BIGNUM *r, const BIGNUM *a);
 
 // BN_set_bit sets the |n|th, least-significant bit in |a|. For example, if |a|
 // is 2 then setting bit zero will make it 3. It returns one on success or zero
 // on allocation failure.
 OPENSSL_EXPORT int BN_set_bit(BIGNUM *a, int n);
 
 // BN_clear_bit clears the |n|th, least-significant bit in |a|. For example, if
 // |a| is 3, clearing bit zero will make it two. It returns one on success or
 // zero on allocation failure.
 OPENSSL_EXPORT int BN_clear_bit(BIGNUM *a, int n);
 
 // BN_is_bit_set returns one if the |n|th least-significant bit in |a| exists
 // and is set. Otherwise, it returns zero.
 OPENSSL_EXPORT int BN_is_bit_set(const BIGNUM *a, int n);
 
 // BN_mask_bits truncates |a| so that it is only |n| bits long. It returns one
 // on success or zero if |n| is negative.
 //
 // This differs from OpenSSL which additionally returns zero if |a|'s word
 // length is less than or equal to |n|, rounded down to a number of words. Note
 // word size is platform-dependent, so this behavior is also difficult to rely
 // on in OpenSSL and not very useful.
 OPENSSL_EXPORT int BN_mask_bits(BIGNUM *a, int n);
 
 // BN_count_low_zero_bits returns the number of low-order zero bits in |bn|, or
 // the number of factors of two which divide it. It returns zero if |bn| is
 // zero.
 OPENSSL_EXPORT int BN_count_low_zero_bits(const BIGNUM *bn);
 
 
 // Modulo arithmetic.
 
 // BN_mod_word returns |a| mod |w| or (BN_ULONG)-1 on error.
 OPENSSL_EXPORT BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
 
 // BN_mod_pow2 sets |r| = |a| mod 2^|e|. It returns 1 on success and
 // 0 on error.
 OPENSSL_EXPORT int BN_mod_pow2(BIGNUM *r, const BIGNUM *a, size_t e);
 
 // BN_nnmod_pow2 sets |r| = |a| mod 2^|e| where |r| is always positive.
 // It returns 1 on success and 0 on error.
 OPENSSL_EXPORT int BN_nnmod_pow2(BIGNUM *r, const BIGNUM *a, size_t e);
 
 // BN_mod is a helper macro that calls |BN_div| and discards the quotient.
 #define BN_mod(rem, numerator, divisor, ctx) \
   BN_div(NULL, (rem), (numerator), (divisor), (ctx))
 
 // BN_nnmod is a non-negative modulo function. It acts like |BN_mod|, but 0 <=
 // |rem| < |divisor| is always true. It returns one on success and zero on
 // error.
 OPENSSL_EXPORT int BN_nnmod(BIGNUM *rem, const BIGNUM *numerator,
                             const BIGNUM *divisor, BN_CTX *ctx);
 
 // BN_mod_add sets |r| = |a| + |b| mod |m|. It returns one on success and zero
 // on error.
 OPENSSL_EXPORT int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                               const BIGNUM *m, BN_CTX *ctx);
 
 // BN_mod_add_quick acts like |BN_mod_add| but requires that |a| and |b| be
 // non-negative and less than |m|.
 OPENSSL_EXPORT int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                                     const BIGNUM *m);
 
 // BN_mod_sub sets |r| = |a| - |b| mod |m|. It returns one on success and zero
 // on error.
 OPENSSL_EXPORT int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                               const BIGNUM *m, BN_CTX *ctx);
 
 // BN_mod_sub_quick acts like |BN_mod_sub| but requires that |a| and |b| be
 // non-negative and less than |m|.
 OPENSSL_EXPORT int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                                     const BIGNUM *m);
 
 // BN_mod_mul sets |r| = |a|*|b| mod |m|. It returns one on success and zero
 // on error.
 OPENSSL_EXPORT int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                               const BIGNUM *m, BN_CTX *ctx);
 
 // BN_mod_sqr sets |r| = |a|^2 mod |m|. It returns one on success and zero
 // on error.
 OPENSSL_EXPORT int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
                               BN_CTX *ctx);
 
 // BN_mod_lshift sets |r| = (|a| << n) mod |m|, where |r| and |a| may be the
 // same pointer. It returns one on success and zero on error.
 OPENSSL_EXPORT int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n,
                                  const BIGNUM *m, BN_CTX *ctx);
 
 // BN_mod_lshift_quick acts like |BN_mod_lshift| but requires that |a| be
 // non-negative and less than |m|.
 OPENSSL_EXPORT int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n,
                                        const BIGNUM *m);
 
 // BN_mod_lshift1 sets |r| = (|a| << 1) mod |m|, where |r| and |a| may be the
 // same pointer. It returns one on success and zero on error.
 OPENSSL_EXPORT int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
                                   BN_CTX *ctx);
 
 // BN_mod_lshift1_quick acts like |BN_mod_lshift1| but requires that |a| be
 // non-negative and less than |m|.
 OPENSSL_EXPORT int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a,
                                         const BIGNUM *m);
 
 // BN_mod_sqrt returns a newly-allocated |BIGNUM|, r, such that
 // r^2 == a (mod p). It returns NULL on error or if |a| is not a square mod |p|.
 // In the latter case, it will add |BN_R_NOT_A_SQUARE| to the error queue.
 // If |a| is a square and |p| > 2, there are two possible square roots. This
 // function may return either and may even select one non-deterministically.
 //
 // This function only works if |p| is a prime. If |p| is composite, it may fail
 // or return an arbitrary value. Callers should not pass attacker-controlled
 // values of |p|.
 OPENSSL_EXPORT BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p,
                                    BN_CTX *ctx);
 
 
 // Random and prime number generation.
 
 // The following are values for the |top| parameter of |BN_rand|.
 #define BN_RAND_TOP_ANY    (-1)
 #define BN_RAND_TOP_ONE     0
 #define BN_RAND_TOP_TWO     1
 
 // The following are values for the |bottom| parameter of |BN_rand|.
 #define BN_RAND_BOTTOM_ANY  0
 #define BN_RAND_BOTTOM_ODD  1
 
 // BN_rand sets |rnd| to a random number of length |bits|. It returns one on
 // success and zero otherwise.
 //
 // |top| must be one of the |BN_RAND_TOP_*| values. If |BN_RAND_TOP_ONE|, the
 // most-significant bit, if any, will be set. If |BN_RAND_TOP_TWO|, the two
 // most significant bits, if any, will be set. If |BN_RAND_TOP_ANY|, no extra
 // action will be taken and |BN_num_bits(rnd)| may not equal |bits| if the most
 // significant bits randomly ended up as zeros.
 //
 // |bottom| must be one of the |BN_RAND_BOTTOM_*| values. If
 // |BN_RAND_BOTTOM_ODD|, the least-significant bit, if any, will be set. If
 // |BN_RAND_BOTTOM_ANY|, no extra action will be taken.
 OPENSSL_EXPORT int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
 
 // BN_pseudo_rand is an alias for |BN_rand|.
 OPENSSL_EXPORT int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
 
 // BN_rand_range is equivalent to |BN_rand_range_ex| with |min_inclusive| set
 // to zero and |max_exclusive| set to |range|.
 OPENSSL_EXPORT int BN_rand_range(BIGNUM *rnd, const BIGNUM *range);
 
 // BN_rand_range_ex sets |rnd| to a random value in
 // [min_inclusive..max_exclusive). It returns one on success and zero
 // otherwise.
 OPENSSL_EXPORT int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive,
                                     const BIGNUM *max_exclusive);
 
 // BN_pseudo_rand_range is an alias for BN_rand_range.
 OPENSSL_EXPORT int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range);
 
 #define BN_GENCB_GENERATED 0
 #define BN_GENCB_PRIME_TEST 1
 
 // bn_gencb_st, or |BN_GENCB|, holds a callback function that is used by
 // generation functions that can take a very long time to complete. Use
 // |BN_GENCB_set| to initialise a |BN_GENCB| structure.
 //
 // The callback receives the address of that |BN_GENCB| structure as its last
 // argument and the user is free to put an arbitrary pointer in |arg|. The other
 // arguments are set as follows:
 // - event=BN_GENCB_GENERATED, n=i:   after generating the i'th possible prime
 //                                    number.
 // - event=BN_GENCB_PRIME_TEST, n=-1: when finished trial division primality
 //                                    checks.
 // - event=BN_GENCB_PRIME_TEST, n=i:  when the i'th primality test has finished.
 //
 // The callback can return zero to abort the generation progress or one to
 // allow it to continue.
 //
 // When other code needs to call a BN generation function it will often take a
 // BN_GENCB argument and may call the function with other argument values.
 struct bn_gencb_st {
   void *arg;        // callback-specific data
   int (*callback)(int event, int n, struct bn_gencb_st *);
 };
 
 // BN_GENCB_new returns a newly-allocated |BN_GENCB| object, or NULL on
 // allocation failure. The result must be released with |BN_GENCB_free| when
 // done.
 OPENSSL_EXPORT BN_GENCB *BN_GENCB_new(void);
 
 // BN_GENCB_free releases memory associated with |callback|.
 OPENSSL_EXPORT void BN_GENCB_free(BN_GENCB *callback);
 
 // BN_GENCB_set configures |callback| to call |f| and sets |callout->arg| to
 // |arg|.
 OPENSSL_EXPORT void BN_GENCB_set(BN_GENCB *callback,
                                  int (*f)(int event, int n, BN_GENCB *),
                                  void *arg);
 
 // BN_GENCB_call calls |callback|, if not NULL, and returns the return value of
 // the callback, or 1 if |callback| is NULL.
 OPENSSL_EXPORT int BN_GENCB_call(BN_GENCB *callback, int event, int n);
 
 // BN_GENCB_get_arg returns |callback->arg|.
 OPENSSL_EXPORT void *BN_GENCB_get_arg(const BN_GENCB *callback);
 
 // BN_generate_prime_ex sets |ret| to a prime number of |bits| length. If safe
 // is non-zero then the prime will be such that (ret-1)/2 is also a prime.
 // (This is needed for Diffie-Hellman groups to ensure that the only subgroups
 // are of size 2 and (p-1)/2.).
 //
 // If |add| is not NULL, the prime will fulfill the condition |ret| % |add| ==
 // |rem| in order to suit a given generator. (If |rem| is NULL then |ret| %
 // |add| == 1.)
 //
 // If |cb| is not NULL, it will be called during processing to give an
 // indication of progress. See the comments for |BN_GENCB|. It returns one on
 // success and zero otherwise.
 OPENSSL_EXPORT int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
                                         const BIGNUM *add, const BIGNUM *rem,
                                         BN_GENCB *cb);
 
 // BN_prime_checks_for_validation can be used as the |checks| argument to the
 // primarily testing functions when validating an externally-supplied candidate
 // prime. It gives a false positive rate of at most 2^{-128}. (The worst case
 // false positive rate for a single iteration is 1/4 per
 // https://eprint.iacr.org/2018/749. (1/4)^64 = 2^{-128}.)
 #define BN_prime_checks_for_validation 64
 
 // BN_prime_checks_for_generation can be used as the |checks| argument to the
 // primality testing functions when generating random primes. It gives a false
 // positive rate at most the security level of the corresponding RSA key size.
 //
 // Note this value only performs enough checks if the candidate prime was
 // selected randomly. If validating an externally-supplied candidate, especially
 // one that may be selected adversarially, use |BN_prime_checks_for_validation|
 // instead.
 #define BN_prime_checks_for_generation 0
 
 // bn_primality_result_t enumerates the outcomes of primality-testing.
 enum bn_primality_result_t {
   bn_probably_prime,
   bn_composite,
   bn_non_prime_power_composite,
 };
 
 // BN_enhanced_miller_rabin_primality_test tests whether |w| is probably a prime
 // number using the Enhanced Miller-Rabin Test (FIPS 186-4 C.3.2) with
 // |checks| iterations and returns the result in |out_result|. Enhanced
 // Miller-Rabin tests primality for odd integers greater than 3, returning
 // |bn_probably_prime| if the number is probably prime,
 // |bn_non_prime_power_composite| if the number is a composite that is not the
 // power of a single prime, and |bn_composite| otherwise. It returns one on
 // success and zero on failure. If |cb| is not NULL, then it is called during
 // each iteration of the primality test.
 //
 // See |BN_prime_checks_for_validation| and |BN_prime_checks_for_generation| for
 // recommended values of |checks|.
 OPENSSL_EXPORT int BN_enhanced_miller_rabin_primality_test(
     enum bn_primality_result_t *out_result, const BIGNUM *w, int checks,
     BN_CTX *ctx, BN_GENCB *cb);
 
 // BN_primality_test sets |*is_probably_prime| to one if |candidate| is
 // probably a prime number by the Miller-Rabin test or zero if it's certainly
 // not.
 //
 // If |do_trial_division| is non-zero then |candidate| will be tested against a
 // list of small primes before Miller-Rabin tests. The probability of this
 // function returning a false positive is at most 2^{2*checks}. See
 // |BN_prime_checks_for_validation| and |BN_prime_checks_for_generation| for
 // recommended values of |checks|.
 //
 // If |cb| is not NULL then it is called during the checking process. See the
 // comment above |BN_GENCB|.
 //
 // The function returns one on success and zero on error.
 OPENSSL_EXPORT int BN_primality_test(int *is_probably_prime,
                                      const BIGNUM *candidate, int checks,
                                      BN_CTX *ctx, int do_trial_division,
                                      BN_GENCB *cb);
 
 // BN_is_prime_fasttest_ex returns one if |candidate| is probably a prime
 // number by the Miller-Rabin test, zero if it's certainly not and -1 on error.
 //
 // If |do_trial_division| is non-zero then |candidate| will be tested against a
 // list of small primes before Miller-Rabin tests. The probability of this
 // function returning one when |candidate| is composite is at most 2^{2*checks}.
 // See |BN_prime_checks_for_validation| and |BN_prime_checks_for_generation| for
 // recommended values of |checks|.
 //
 // If |cb| is not NULL then it is called during the checking process. See the
 // comment above |BN_GENCB|.
 //
 // WARNING: deprecated. Use |BN_primality_test|.
 OPENSSL_EXPORT int BN_is_prime_fasttest_ex(const BIGNUM *candidate, int checks,
                                            BN_CTX *ctx, int do_trial_division,
                                            BN_GENCB *cb);
 
 // BN_is_prime_ex acts the same as |BN_is_prime_fasttest_ex| with
 // |do_trial_division| set to zero.
 //
 // WARNING: deprecated: Use |BN_primality_test|.
 OPENSSL_EXPORT int BN_is_prime_ex(const BIGNUM *candidate, int checks,
                                   BN_CTX *ctx, BN_GENCB *cb);
 
 
 // Number theory functions
 
 // BN_gcd sets |r| = gcd(|a|, |b|). It returns one on success and zero
 // otherwise.
 OPENSSL_EXPORT int BN_gcd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                           BN_CTX *ctx);
 
 // BN_mod_inverse sets |out| equal to |a|^-1, mod |n|. If |out| is NULL, a
 // fresh BIGNUM is allocated. It returns the result or NULL on error.
 //
 // If |n| is even then the operation is performed using an algorithm that avoids
 // some branches but which isn't constant-time. This function shouldn't be used
 // for secret values; use |BN_mod_inverse_blinded| instead. Or, if |n| is
 // guaranteed to be prime, use
 // |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
 // advantage of Fermat's Little Theorem.
 OPENSSL_EXPORT BIGNUM *BN_mod_inverse(BIGNUM *out, const BIGNUM *a,
                                       const BIGNUM *n, BN_CTX *ctx);
 
 // BN_mod_inverse_blinded sets |out| equal to |a|^-1, mod |n|, where |n| is the
 // Montgomery modulus for |mont|. |a| must be non-negative and must be less
 // than |n|. |n| must be greater than 1. |a| is blinded (masked by a random
 // value) to protect it against side-channel attacks. On failure, if the failure
 // was caused by |a| having no inverse mod |n| then |*out_no_inverse| will be
 // set to one; otherwise it will be set to zero.
 //
 // Note this function may incorrectly report |a| has no inverse if the random
 // blinding value has no inverse. It should only be used when |n| has few
 // non-invertible elements, such as an RSA modulus.
 OPENSSL_EXPORT int BN_mod_inverse_blinded(BIGNUM *out, int *out_no_inverse,
                                           const BIGNUM *a,
                                           const BN_MONT_CTX *mont, BN_CTX *ctx);
 
 // BN_mod_inverse_odd sets |out| equal to |a|^-1, mod |n|. |a| must be
 // non-negative and must be less than |n|. |n| must be odd. This function
 // shouldn't be used for secret values; use |BN_mod_inverse_blinded| instead.
 // Or, if |n| is guaranteed to be prime, use
 // |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
 // advantage of Fermat's Little Theorem. It returns one on success or zero on
 // failure. On failure, if the failure was caused by |a| having no inverse mod
 // |n| then |*out_no_inverse| will be set to one; otherwise it will be set to
 // zero.
 int BN_mod_inverse_odd(BIGNUM *out, int *out_no_inverse, const BIGNUM *a,
                        const BIGNUM *n, BN_CTX *ctx);
 
 
 // Montgomery arithmetic.
 
 // BN_MONT_CTX contains the precomputed values needed to work in a specific
 // Montgomery domain.
 
 // BN_MONT_CTX_new_for_modulus returns a fresh |BN_MONT_CTX| given the modulus,
 // |mod| or NULL on error. Note this function assumes |mod| is public.
 OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new_for_modulus(const BIGNUM *mod,
                                                         BN_CTX *ctx);
 
 // BN_MONT_CTX_new_consttime behaves like |BN_MONT_CTX_new_for_modulus| but
 // treats |mod| as secret.
 OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new_consttime(const BIGNUM *mod,
                                                       BN_CTX *ctx);
 
 // BN_MONT_CTX_free frees memory associated with |mont|.
 OPENSSL_EXPORT void BN_MONT_CTX_free(BN_MONT_CTX *mont);
 
 // BN_MONT_CTX_copy sets |to| equal to |from|. It returns |to| on success or
 // NULL on error.
 OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to,
                                              const BN_MONT_CTX *from);
 
 // BN_to_montgomery sets |ret| equal to |a| in the Montgomery domain. |a| is
 // assumed to be in the range [0, n), where |n| is the Montgomery modulus. It
 // returns one on success or zero on error.
 OPENSSL_EXPORT int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a,
                                     const BN_MONT_CTX *mont, BN_CTX *ctx);
 
 // BN_from_montgomery sets |ret| equal to |a| * R^-1, i.e. translates values out
 // of the Montgomery domain. |a| is assumed to be in the range [0, n*R), where
 // |n| is the Montgomery modulus. Note n < R, so inputs in the range [0, n*n)
 // are valid. This function returns one on success or zero on error.
 OPENSSL_EXPORT int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a,
                                       const BN_MONT_CTX *mont, BN_CTX *ctx);
 
 // BN_mod_mul_montgomery set |r| equal to |a| * |b|, in the Montgomery domain.
 // Both |a| and |b| must already be in the Montgomery domain (by
 // |BN_to_montgomery|). In particular, |a| and |b| are assumed to be in the
 // range [0, n), where |n| is the Montgomery modulus. It returns one on success
 // or zero on error.
 OPENSSL_EXPORT int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a,
                                          const BIGNUM *b,
                                          const BN_MONT_CTX *mont, BN_CTX *ctx);
 
 
 // Exponentiation.
 
 // BN_exp sets |r| equal to |a|^{|p|}. It does so with a square-and-multiply
 // algorithm that leaks side-channel information. It returns one on success or
 // zero otherwise.
 OPENSSL_EXPORT int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                           BN_CTX *ctx);
 
 // BN_mod_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
 // algorithm for the values provided. It returns one on success or zero
 // otherwise. The |BN_mod_exp_mont_consttime| variant must be used if the
 // exponent is secret.
 OPENSSL_EXPORT int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                               const BIGNUM *m, BN_CTX *ctx);
 
 // BN_mod_exp_mont behaves like |BN_mod_exp| but treats |a| as secret and
 // requires 0 <= |a| < |m|.
 OPENSSL_EXPORT int BN_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                                    const BIGNUM *m, BN_CTX *ctx,
                                    const BN_MONT_CTX *mont);
 
 // BN_mod_exp_mont_consttime behaves like |BN_mod_exp| but treats |a|, |p|, and
 // |m| as secret and requires 0 <= |a| < |m|.
 OPENSSL_EXPORT int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a,
                                              const BIGNUM *p, const BIGNUM *m,
                                              BN_CTX *ctx,
                                              const BN_MONT_CTX *mont);
 
 
 // Deprecated functions
 
 // BN_bn2mpi serialises the value of |in| to |out|, using a format that consists
 // of the number's length in bytes represented as a 4-byte big-endian number,
 // and the number itself in big-endian format, where the most significant bit
 // signals a negative number. (The representation of numbers with the MSB set is
 // prefixed with null byte). |out| must have sufficient space available; to
 // find the needed amount of space, call the function with |out| set to NULL.
 OPENSSL_EXPORT size_t BN_bn2mpi(const BIGNUM *in, uint8_t *out);
 
 // BN_mpi2bn parses |len| bytes from |in| and returns the resulting value. The
 // bytes at |in| are expected to be in the format emitted by |BN_bn2mpi|.
 //
 // If |out| is NULL then a fresh |BIGNUM| is allocated and returned, otherwise
 // |out| is reused and returned. On error, NULL is returned and the error queue
 // is updated.
 OPENSSL_EXPORT BIGNUM *BN_mpi2bn(const uint8_t *in, size_t len, BIGNUM *out);
 
 // BN_mod_exp_mont_word is like |BN_mod_exp_mont| except that the base |a| is
 // given as a |BN_ULONG| instead of a |BIGNUM *|. It returns one on success
 // or zero otherwise.
 OPENSSL_EXPORT int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
                                         const BIGNUM *m, BN_CTX *ctx,
                                         const BN_MONT_CTX *mont);
 
 // BN_mod_exp2_mont calculates (a1^p1) * (a2^p2) mod m. It returns 1 on success
 // or zero otherwise.
 OPENSSL_EXPORT int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1,
                                     const BIGNUM *p1, const BIGNUM *a2,
                                     const BIGNUM *p2, const BIGNUM *m,
                                     BN_CTX *ctx, const BN_MONT_CTX *mont);
 
 // BN_MONT_CTX_new returns a fresh |BN_MONT_CTX| or NULL on allocation failure.
 // Use |BN_MONT_CTX_new_for_modulus| instead.
 OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new(void);
 
 // BN_MONT_CTX_set sets up a Montgomery context given the modulus, |mod|. It
 // returns one on success and zero on error. Use |BN_MONT_CTX_new_for_modulus|
 // instead.
 OPENSSL_EXPORT int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod,
                                    BN_CTX *ctx);
 
 // BN_bn2binpad behaves like |BN_bn2bin_padded|, but it returns |len| on success
 // and -1 on error.
 //
 // Use |BN_bn2bin_padded| instead. It is |size_t|-clean.
 OPENSSL_EXPORT int BN_bn2binpad(const BIGNUM *in, uint8_t *out, int len);
 
 // BN_bn2lebinpad behaves like |BN_bn2le_padded|, but it returns |len| on
 // success and -1 on error.
 //
 // Use |BN_bn2le_padded| instead. It is |size_t|-clean.
 OPENSSL_EXPORT int BN_bn2lebinpad(const BIGNUM *in, uint8_t *out, int len);
 
 // BN_prime_checks is a deprecated alias for |BN_prime_checks_for_validation|.
 // Use |BN_prime_checks_for_generation| or |BN_prime_checks_for_validation|
 // instead. (This defaults to the |_for_validation| value in order to be
 // conservative.)
 #define BN_prime_checks BN_prime_checks_for_validation
 
 // BN_secure_new calls |BN_new|.
 OPENSSL_EXPORT BIGNUM *BN_secure_new(void);
 
 // BN_le2bn calls |BN_lebin2bn|.
 OPENSSL_EXPORT BIGNUM *BN_le2bn(const uint8_t *in, size_t len, BIGNUM *ret);
 
 
 // Private functions
 
 struct bignum_st {
   // d is a pointer to an array of |width| |BN_BITS2|-bit chunks in
   // little-endian order. This stores the absolute value of the number.
   BN_ULONG *d;
   // width is the number of elements of |d| which are valid. This value is not
   // necessarily minimal; the most-significant words of |d| may be zero.
   // |width| determines a potentially loose upper-bound on the absolute value
   // of the |BIGNUM|.
   //
   // Functions taking |BIGNUM| inputs must compute the same answer for all
   // possible widths. |bn_minimal_width|, |bn_set_minimal_width|, and other
   // helpers may be used to recover the minimal width, provided it is not
   // secret. If it is secret, use a different algorithm. Functions may output
   // minimal or non-minimal |BIGNUM|s depending on secrecy requirements, but
   // those which cause widths to unboundedly grow beyond the minimal value
   // should be documented such.
   //
   // Note this is different from historical |BIGNUM| semantics.
   int width;
   // dmax is number of elements of |d| which are allocated.
   int dmax;
   // neg is one if the number if negative and zero otherwise.
   int neg;
   // flags is a bitmask of |BN_FLG_*| values
   int flags;
 };
 
 struct bn_mont_ctx_st {
   // RR is R^2, reduced modulo |N|. It is used to convert to Montgomery form. It
   // is guaranteed to have the same width as |N|.
   BIGNUM RR;
   // N is the modulus. It is always stored in minimal form, so |N.width|
   // determines R.
   BIGNUM N;
   BN_ULONG n0[2];  // least significant words of (R*Ri-1)/N
 };
 
 OPENSSL_EXPORT unsigned BN_num_bits_word(BN_ULONG l);
 
 #define BN_FLG_MALLOCED 0x01
 #define BN_FLG_STATIC_DATA 0x02
 // |BN_FLG_CONSTTIME| has been removed and intentionally omitted so code relying
 // on it will not compile. Consumers outside BoringSSL should use the
 // higher-level cryptographic algorithms exposed by other modules. Consumers
 // within the library should call the appropriate timing-sensitive algorithm
 // directly.
 
 
 #if defined(__cplusplus)
 }  // extern C
 
 #if !defined(BORINGSSL_NO_CXX)
 extern "C++" {
 
 BSSL_NAMESPACE_BEGIN
 
 BORINGSSL_MAKE_DELETER(BIGNUM, BN_free)
 BORINGSSL_MAKE_DELETER(BN_CTX, BN_CTX_free)
 BORINGSSL_MAKE_DELETER(BN_MONT_CTX, BN_MONT_CTX_free)
 
 class BN_CTXScope {
  public:
   BN_CTXScope(BN_CTX *ctx) : ctx_(ctx) { BN_CTX_start(ctx_); }
   ~BN_CTXScope() { BN_CTX_end(ctx_); }
 
  private:
   BN_CTX *ctx_;
 
   BN_CTXScope(BN_CTXScope &) = delete;
   BN_CTXScope &operator=(BN_CTXScope &) = delete;
 };
 
 BSSL_NAMESPACE_END
 
 }  // extern C++
 #endif
 
 #endif
 
 #define BN_R_ARG2_LT_ARG3 100
 #define BN_R_BAD_RECIPROCAL 101
 #define BN_R_BIGNUM_TOO_LONG 102
 #define BN_R_BITS_TOO_SMALL 103
 #define BN_R_CALLED_WITH_EVEN_MODULUS 104
 #define BN_R_DIV_BY_ZERO 105
 #define BN_R_EXPAND_ON_STATIC_BIGNUM_DATA 106
 #define BN_R_INPUT_NOT_REDUCED 107
 #define BN_R_INVALID_RANGE 108
 #define BN_R_NEGATIVE_NUMBER 109
 #define BN_R_NOT_A_SQUARE 110
 #define BN_R_NOT_INITIALIZED 111
 #define BN_R_NO_INVERSE 112
 #define BN_R_PRIVATE_KEY_TOO_LARGE 113
 #define BN_R_P_IS_NOT_PRIME 114
 #define BN_R_TOO_MANY_ITERATIONS 115
 #define BN_R_TOO_MANY_TEMPORARY_VARIABLES 116
 #define BN_R_BAD_ENCODING 117
 #define BN_R_ENCODE_ERROR 118
 #define BN_R_INVALID_INPUT 119
 
 #endif  // OPENSSL_HEADER_BN_H