BN_BLINDING_new(3)                  OpenSSL                 BN_BLINDING_new(3)



NAME
       BN_BLINDING_new, BN_BLINDING_free, BN_BLINDING_update, BN_BLINDING_con-
       vert, BN_BLINDING_invert, BN_BLINDING_convert_ex, BN_BLIND-
       ING_invert_ex, BN_BLINDING_set_thread, BN_BLINDING_cmp_thread,
       BN_BLINDING_get_flags, BN_BLINDING_set_flags, BN_BLINDING_create_param
       - blinding related BIGNUM functions.

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/bn.h>

        BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai,
               BIGNUM *mod);
        void BN_BLINDING_free(BN_BLINDING *b);
        int BN_BLINDING_update(BN_BLINDING *b,BN_CTX *ctx);
        int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
        int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
        int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b,
               BN_CTX *ctx);
        int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
               BN_CTX *ctx);

        void BN_BLINDING_set_thread(BN_BLINDING *);
        int BN_BLINDING_cmp_thread(const BN_BLINDING *,
               const CRYPTO_THREADID *);
        unsigned long BN_BLINDING_get_flags(const BN_BLINDING *);
        void BN_BLINDING_set_flags(BN_BLINDING *, unsigned long);
        BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
               const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
               int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                                 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
               BN_MONT_CTX *m_ctx);

DESCRIPTION
       BN_BLINDING_new() allocates a new BN_BLINDING structure and copies the
       A and Ai values into the newly created BN_BLINDING object.

       BN_BLINDING_free() frees the BN_BLINDING structure.

       BN_BLINDING_update() updates the BN_BLINDING parameters by squaring the
       A and Ai or, after specific number of uses and if the necessary parame-
       ters are set, by re-creating the blinding parameters.

       BN_BLINDING_convert_ex() multiplies n with the blinding factor A.  If r
       is not NULL a copy the inverse blinding factor Ai will be returned in r
       (this is useful if a RSA object is shared amoung several threads).
       BN_BLINDING_invert_ex() multiplies n with the inverse blinding factor
       Ai. If r is not NULL it will be used as the inverse blinding.

       BN_BLINDING_convert() and BN_BLINDING_invert() are wrapper functions
       for BN_BLINDING_convert_ex() and BN_BLINDING_invert_ex() with r set to
       NULL.

       BN_BLINDING_set_thread() and BN_BLINDING_cmp_thread() set and compare
       the "thread id" of the BN_BLINDING structure, allowing users of the
       BN_BLINDING structure to provide proper locking if needed for multi-
       threaded use.

       BN_BLINDING_get_flags() returns the BN_BLINDING flags. Currently there
       are two supported flags: BN_BLINDING_NO_UPDATE and BN_BLIND-
       ING_NO_RECREATE. BN_BLINDING_NO_UPDATE inhibits the automatic update of
       the BN_BLINDING parameters after each use and BN_BLINDING_NO_RECREATE
       inhibits the automatic re-creation of the BN_BLINDING parameters after
       a fixed number of uses (currently 32). In newly allocated BN_BLINDING
       objects no flags are set.  BN_BLINDING_set_flags() sets the BN_BLINDING
       parameters flags.

       BN_BLINDING_create_param() creates new BN_BLINDING parameters using the
       exponent e and the modulus m. bn_mod_exp and m_ctx can be used to pass
       special functions for exponentiation (normally BN_mod_exp_mont() and
       BN_MONT_CTX).

RETURN VALUES
       BN_BLINDING_new() returns the newly allocated BN_BLINDING structure or
       NULL in case of an error.

       BN_BLINDING_update(), BN_BLINDING_convert(), BN_BLINDING_invert(),
       BN_BLINDING_convert_ex() and BN_BLINDING_invert_ex() return 1 on suc-
       cess and 0 if an error occured.

       BN_BLINDING_get_thread_id() returns the thread id (a unsigned long
       value) or 0 if not set.  BN_BLINDING_cmp_thread() returns 0 if the
       thread id associated with the BN_BLINDING structure equals the provided
       thread id (which can be obtained by CRYPTO_THREADID_set()), otherwise
       it returns -1 or +1 to indicate the thread ids are different (if the
       target architecture supports ordering of thread ids, this follows the
       traditional "cmp" semantics of memcmp() or strcmp()).

       BN_BLINDING_get_flags() returns the currently set BN_BLINDING flags (a
       unsigned long value).

       BN_BLINDING_create_param() returns the newly created BN_BLINDING param-
       eters or NULL on error.

SEE ALSO
       openssl_bn(3)

HISTORY
       BN_BLINDING_convert_ex, BN_BLINDIND_invert_ex, BN_BLIND-
       ING_get_thread_id, BN_BLINDING_set_thread_id, BN_BLINDING_set_flags,
       BN_BLINDING_get_flags and BN_BLINDING_create_param were first intro-
       duced in OpenSSL 0.9.8

       BN_BLINDING_get_thread_idptr, BN_BLINDING_set_thread_idptr were first
       introduced in OpenSSL 0.9.9

       BN_BLINDING_get_thread_id, BN_BLINDING_set_thread_id, BN_BLIND-
       ING_get_thread_idptr, BN_BLINDING_set_thread_idptr were all deprecated
       in favour of BN_BLINDING_set_thread, BN_BLINDING_cmp_thread which were
       introduced in OpenSSL 0.9.9

AUTHOR
       Nils Larsch for the OpenSSL project (http://www.openssl.org).



0.9.9-dev                         2008-05-09                BN_BLINDING_new(3)
