From 6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:29:51 +0200 Subject: Adding upstream version 2.06. Signed-off-by: Daniel Baumann --- grub-core/lib/libgcrypt/mpi/mpi-inv.c | 267 ++++++++++++++++++++++++++++++++++ 1 file changed, 267 insertions(+) create mode 100644 grub-core/lib/libgcrypt/mpi/mpi-inv.c (limited to 'grub-core/lib/libgcrypt/mpi/mpi-inv.c') diff --git a/grub-core/lib/libgcrypt/mpi/mpi-inv.c b/grub-core/lib/libgcrypt/mpi/mpi-inv.c new file mode 100644 index 0000000..5d26946 --- /dev/null +++ b/grub-core/lib/libgcrypt/mpi/mpi-inv.c @@ -0,0 +1,267 @@ +/* mpi-inv.c - MPI functions + * Copyright (C) 1998, 2001, 2002, 2003 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this program; if not, see . + */ + +#include +#include +#include +#include "mpi-internal.h" +#include "g10lib.h" + +/**************** + * Calculate the multiplicative inverse X of A mod N + * That is: Find the solution x for + * 1 = (a*x) mod n + */ +int +gcry_mpi_invm( gcry_mpi_t x, gcry_mpi_t a, gcry_mpi_t n ) +{ +#if 0 + gcry_mpi_t u, v, u1, u2, u3, v1, v2, v3, q, t1, t2, t3; + gcry_mpi_t ta, tb, tc; + + u = mpi_copy(a); + v = mpi_copy(n); + u1 = mpi_alloc_set_ui(1); + u2 = mpi_alloc_set_ui(0); + u3 = mpi_copy(u); + v1 = mpi_alloc_set_ui(0); + v2 = mpi_alloc_set_ui(1); + v3 = mpi_copy(v); + q = mpi_alloc( mpi_get_nlimbs(u)+1 ); + t1 = mpi_alloc( mpi_get_nlimbs(u)+1 ); + t2 = mpi_alloc( mpi_get_nlimbs(u)+1 ); + t3 = mpi_alloc( mpi_get_nlimbs(u)+1 ); + while( mpi_cmp_ui( v3, 0 ) ) { + mpi_fdiv_q( q, u3, v3 ); + mpi_mul(t1, v1, q); mpi_mul(t2, v2, q); mpi_mul(t3, v3, q); + mpi_sub(t1, u1, t1); mpi_sub(t2, u2, t2); mpi_sub(t3, u3, t3); + mpi_set(u1, v1); mpi_set(u2, v2); mpi_set(u3, v3); + mpi_set(v1, t1); mpi_set(v2, t2); mpi_set(v3, t3); + } + /* log_debug("result:\n"); + log_mpidump("q =", q ); + log_mpidump("u1=", u1); + log_mpidump("u2=", u2); + log_mpidump("u3=", u3); + log_mpidump("v1=", v1); + log_mpidump("v2=", v2); */ + mpi_set(x, u1); + + mpi_free(u1); + mpi_free(u2); + mpi_free(u3); + mpi_free(v1); + mpi_free(v2); + mpi_free(v3); + mpi_free(q); + mpi_free(t1); + mpi_free(t2); + mpi_free(t3); + mpi_free(u); + mpi_free(v); +#elif 0 + /* Extended Euclid's algorithm (See TAOCP Vol II, 4.5.2, Alg X) + * modified according to Michael Penk's solution for Exercise 35 */ + + /* FIXME: we can simplify this in most cases (see Knuth) */ + gcry_mpi_t u, v, u1, u2, u3, v1, v2, v3, t1, t2, t3; + unsigned k; + int sign; + + u = mpi_copy(a); + v = mpi_copy(n); + for(k=0; !mpi_test_bit(u,0) && !mpi_test_bit(v,0); k++ ) { + mpi_rshift(u, u, 1); + mpi_rshift(v, v, 1); + } + + + u1 = mpi_alloc_set_ui(1); + u2 = mpi_alloc_set_ui(0); + u3 = mpi_copy(u); + v1 = mpi_copy(v); /* !-- used as const 1 */ + v2 = mpi_alloc( mpi_get_nlimbs(u) ); mpi_sub( v2, u1, u ); + v3 = mpi_copy(v); + if( mpi_test_bit(u, 0) ) { /* u is odd */ + t1 = mpi_alloc_set_ui(0); + t2 = mpi_alloc_set_ui(1); t2->sign = 1; + t3 = mpi_copy(v); t3->sign = !t3->sign; + goto Y4; + } + else { + t1 = mpi_alloc_set_ui(1); + t2 = mpi_alloc_set_ui(0); + t3 = mpi_copy(u); + } + do { + do { + if( mpi_test_bit(t1, 0) || mpi_test_bit(t2, 0) ) { /* one is odd */ + mpi_add(t1, t1, v); + mpi_sub(t2, t2, u); + } + mpi_rshift(t1, t1, 1); + mpi_rshift(t2, t2, 1); + mpi_rshift(t3, t3, 1); + Y4: + ; + } while( !mpi_test_bit( t3, 0 ) ); /* while t3 is even */ + + if( !t3->sign ) { + mpi_set(u1, t1); + mpi_set(u2, t2); + mpi_set(u3, t3); + } + else { + mpi_sub(v1, v, t1); + sign = u->sign; u->sign = !u->sign; + mpi_sub(v2, u, t2); + u->sign = sign; + sign = t3->sign; t3->sign = !t3->sign; + mpi_set(v3, t3); + t3->sign = sign; + } + mpi_sub(t1, u1, v1); + mpi_sub(t2, u2, v2); + mpi_sub(t3, u3, v3); + if( t1->sign ) { + mpi_add(t1, t1, v); + mpi_sub(t2, t2, u); + } + } while( mpi_cmp_ui( t3, 0 ) ); /* while t3 != 0 */ + /* mpi_lshift( u3, k ); */ + mpi_set(x, u1); + + mpi_free(u1); + mpi_free(u2); + mpi_free(u3); + mpi_free(v1); + mpi_free(v2); + mpi_free(v3); + mpi_free(t1); + mpi_free(t2); + mpi_free(t3); +#else + /* Extended Euclid's algorithm (See TAOCP Vol II, 4.5.2, Alg X) + * modified according to Michael Penk's solution for Exercise 35 + * with further enhancement */ + gcry_mpi_t u, v, u1, u2=NULL, u3, v1, v2=NULL, v3, t1, t2=NULL, t3; + unsigned k; + int sign; + int odd ; + + u = mpi_copy(a); + v = mpi_copy(n); + + for(k=0; !mpi_test_bit(u,0) && !mpi_test_bit(v,0); k++ ) { + mpi_rshift(u, u, 1); + mpi_rshift(v, v, 1); + } + odd = mpi_test_bit(v,0); + + u1 = mpi_alloc_set_ui(1); + if( !odd ) + u2 = mpi_alloc_set_ui(0); + u3 = mpi_copy(u); + v1 = mpi_copy(v); + if( !odd ) { + v2 = mpi_alloc( mpi_get_nlimbs(u) ); + mpi_sub( v2, u1, u ); /* U is used as const 1 */ + } + v3 = mpi_copy(v); + if( mpi_test_bit(u, 0) ) { /* u is odd */ + t1 = mpi_alloc_set_ui(0); + if( !odd ) { + t2 = mpi_alloc_set_ui(1); t2->sign = 1; + } + t3 = mpi_copy(v); t3->sign = !t3->sign; + goto Y4; + } + else { + t1 = mpi_alloc_set_ui(1); + if( !odd ) + t2 = mpi_alloc_set_ui(0); + t3 = mpi_copy(u); + } + do { + do { + if( !odd ) { + if( mpi_test_bit(t1, 0) || mpi_test_bit(t2, 0) ) { /* one is odd */ + mpi_add(t1, t1, v); + mpi_sub(t2, t2, u); + } + mpi_rshift(t1, t1, 1); + mpi_rshift(t2, t2, 1); + mpi_rshift(t3, t3, 1); + } + else { + if( mpi_test_bit(t1, 0) ) + mpi_add(t1, t1, v); + mpi_rshift(t1, t1, 1); + mpi_rshift(t3, t3, 1); + } + Y4: + ; + } while( !mpi_test_bit( t3, 0 ) ); /* while t3 is even */ + + if( !t3->sign ) { + mpi_set(u1, t1); + if( !odd ) + mpi_set(u2, t2); + mpi_set(u3, t3); + } + else { + mpi_sub(v1, v, t1); + sign = u->sign; u->sign = !u->sign; + if( !odd ) + mpi_sub(v2, u, t2); + u->sign = sign; + sign = t3->sign; t3->sign = !t3->sign; + mpi_set(v3, t3); + t3->sign = sign; + } + mpi_sub(t1, u1, v1); + if( !odd ) + mpi_sub(t2, u2, v2); + mpi_sub(t3, u3, v3); + if( t1->sign ) { + mpi_add(t1, t1, v); + if( !odd ) + mpi_sub(t2, t2, u); + } + } while( mpi_cmp_ui( t3, 0 ) ); /* while t3 != 0 */ + /* mpi_lshift( u3, k ); */ + mpi_set(x, u1); + + mpi_free(u1); + mpi_free(v1); + mpi_free(t1); + if( !odd ) { + mpi_free(u2); + mpi_free(v2); + mpi_free(t2); + } + mpi_free(u3); + mpi_free(v3); + mpi_free(t3); + + mpi_free(u); + mpi_free(v); +#endif + return 1; +} -- cgit v1.2.3