mpi: Add MPI helper modular exponentiation, Least Leak Intended.
* mpi/Makefile.am (libmpi_la_SOURCES): Add mpih-pow.c. * mpi/mpi-internal.h (_gcry_mpih_powm_lli): New. * mpi/mpi-pow.c (_gcry_mpi_get_powm_config): New. (USE_ALGORITHM_LLI_EXPONENTIATION): New, enabled as default. [USE_ALGORITHM_LLI_EXPONENTIATION] (_gcry_mpi_powm): Call _gcry_mpih_powm_lli when it's on secure memory. * mpi/mpih-pow.c (_gcry_mpih_powm_lli): New. * src/gcrypt-int.h (_gcry_mpi_get_powm_config): New. * src/global.c (print_config): Call _gcry_mpi_get_powm_config.
- GnuPG-bug-id: T7490
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>