[#BN_mod_mul_montgomery]
= BN_mod_mul_montgomery
:mrdocs:

Montgomery multiply `a` and `b` modulo `mont's` modulus into `r.`

== Synopsis

Declared in `<openssl/bn.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
BN_mod_mul_montgomery(
    xref:BIGNUM.adoc[BIGNUM]* r,
    xref:BIGNUM.adoc[BIGNUM] const* a,
    xref:BIGNUM.adoc[BIGNUM] const* b,
    xref:BN_MONT_CTX.adoc[BN_MONT_CTX]* mont,
    xref:BN_CTX.adoc[BN_CTX]* ctx);
----

== Return Value

1 on success, or 0 on error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *r*
| Destination product in the Montgomery domain (or ordinary form depending on inputs).
| *a*
| First factor (typically already in Montgomery form).
| *b*
| Second factor (typically already in Montgomery form).
| *mont*
| Montgomery context from BN_MONT_CTX_set().
| *ctx*
| BN_CTX scratch space.
|===


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