Mercurial > dropbear

annotate libtommath/bn_mp_exteuclid.c @ 1156:a8f4dade70e5

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avoid getpass when not used some systems (like android's bionic) do not provide getpass. you can disable ENABLE_CLI_PASSWORD_AUTH & ENABLE_CLI_INTERACT_AUTH to avoid its use (and rely on pubkey auth), but the link still fails because the support file calls getpass. do not define this func if both of those auth methods are not used.
author Mike Frysinger <vapier@gentoo.org>
date Wed, 21 Oct 2015 22:39:55 +0800
parents 5ff8218bcee9
children 18154dc469f5
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
284
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parents:
diff changeset
1 #include <tommath.h>
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diff changeset
2 #ifdef BN_MP_EXTEUCLID_C
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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4 *
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5 * LibTomMath is a library that provides multiple-precision
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6 * integer arithmetic as well as number theoretic functionality.
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7 *
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diff changeset
8 * The library was designed directly after the MPI library by
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diff changeset
9 * Michael Fromberger but has been written from scratch with
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10 * additional optimizations in place.
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11 *
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Matt Johnston <matt@ucc.asn.au>
parents:
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12 * The library is free for all purposes without any express
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parents:
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13 * guarantee it works.
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14 *
389
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diff changeset
15 * Tom St Denis, [email protected], http://math.libtomcrypt.com
284
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16 */
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17
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Matt Johnston <matt@ucc.asn.au>
parents:
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18 /* Extended euclidean algorithm of (a, b) produces
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diff changeset
19 a*u1 + b*u2 = u3
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parents:
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20 */
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
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diff changeset
21 int mp_exteuclid(mp_int *a, mp_int *b, mp_int *U1, mp_int *U2, mp_int *U3)
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
22 {
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diff changeset
23 mp_int u1,u2,u3,v1,v2,v3,t1,t2,t3,q,tmp;
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Matt Johnston <matt@ucc.asn.au>
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24 int err;
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25
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
26 if ((err = mp_init_multi(&u1, &u2, &u3, &v1, &v2, &v3, &t1, &t2, &t3, &q, &tmp, NULL)) != MP_OKAY) {
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
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27 return err;
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28 }
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29
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diff changeset
30 /* initialize, (u1,u2,u3) = (1,0,a) */
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Matt Johnston <matt@ucc.asn.au>
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31 mp_set(&u1, 1);
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Matt Johnston <matt@ucc.asn.au>
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32 if ((err = mp_copy(a, &u3)) != MP_OKAY) { goto _ERR; }
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Matt Johnston <matt@ucc.asn.au>
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33
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
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34 /* initialize, (v1,v2,v3) = (0,1,b) */
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Matt Johnston <matt@ucc.asn.au>
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diff changeset
35 mp_set(&v2, 1);
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
36 if ((err = mp_copy(b, &v3)) != MP_OKAY) { goto _ERR; }
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Matt Johnston <matt@ucc.asn.au>
parents:
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37
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
38 /* loop while v3 != 0 */
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Matt Johnston <matt@ucc.asn.au>
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diff changeset
39 while (mp_iszero(&v3) == MP_NO) {
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Matt Johnston <matt@ucc.asn.au>
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diff changeset
40 /* q = u3/v3 */
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Matt Johnston <matt@ucc.asn.au>
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diff changeset
41 if ((err = mp_div(&u3, &v3, &q, NULL)) != MP_OKAY) { goto _ERR; }
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Matt Johnston <matt@ucc.asn.au>
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42
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
43 /* (t1,t2,t3) = (u1,u2,u3) - (v1,v2,v3)q */
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Matt Johnston <matt@ucc.asn.au>
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diff changeset
44 if ((err = mp_mul(&v1, &q, &tmp)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
45 if ((err = mp_sub(&u1, &tmp, &t1)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
46 if ((err = mp_mul(&v2, &q, &tmp)) != MP_OKAY) { goto _ERR; }
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
47 if ((err = mp_sub(&u2, &tmp, &t2)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
48 if ((err = mp_mul(&v3, &q, &tmp)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
49 if ((err = mp_sub(&u3, &tmp, &t3)) != MP_OKAY) { goto _ERR; }
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
50
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
51 /* (u1,u2,u3) = (v1,v2,v3) */
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
52 if ((err = mp_copy(&v1, &u1)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
53 if ((err = mp_copy(&v2, &u2)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
54 if ((err = mp_copy(&v3, &u3)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
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55
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
56 /* (v1,v2,v3) = (t1,t2,t3) */
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
57 if ((err = mp_copy(&t1, &v1)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
58 if ((err = mp_copy(&t2, &v2)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
59 if ((err = mp_copy(&t3, &v3)) != MP_OKAY) { goto _ERR; }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
60 }
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
61
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
62 /* make sure U3 >= 0 */
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
63 if (u3.sign == MP_NEG) {
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Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
64 mp_neg(&u1, &u1);
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
65 mp_neg(&u2, &u2);
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
66 mp_neg(&u3, &u3);
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
67 }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
68
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
69 /* copy result out */
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
70 if (U1 != NULL) { mp_exch(U1, &u1); }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
71 if (U2 != NULL) { mp_exch(U2, &u2); }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
72 if (U3 != NULL) { mp_exch(U3, &u3); }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
73
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
74 err = MP_OKAY;
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
75 _ERR: mp_clear_multi(&u1, &u2, &u3, &v1, &v2, &v3, &t1, &t2, &t3, &q, &tmp, NULL);
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
76 return err;
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
77 }
eed26cff980b propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
78 #endif
389
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Matt Johnston <matt@ucc.asn.au>
parents: 284
diff changeset
79
5ff8218bcee9 propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e)
Matt Johnston <matt@ucc.asn.au>
parents: 284
diff changeset
80 /* $Source: /cvs/libtom/libtommath/bn_mp_exteuclid.c,v $ */
5ff8218bcee9 propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e)
Matt Johnston <matt@ucc.asn.au>
parents: 284
diff changeset
81 /* $Revision: 1.3 $ */
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Matt Johnston <matt@ucc.asn.au>
parents: 284
diff changeset
82 /* $Date: 2006/03/31 14:18:44 $ */