1/*
2 *  Simple MPI demonstration program
3 *
4 *  Copyright The Mbed TLS Contributors
5 *  SPDX-License-Identifier: Apache-2.0
6 *
7 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
8 *  not use this file except in compliance with the License.
9 *  You may obtain a copy of the License at
10 *
11 *  http://www.apache.org/licenses/LICENSE-2.0
12 *
13 *  Unless required by applicable law or agreed to in writing, software
14 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 *  See the License for the specific language governing permissions and
17 *  limitations under the License.
18 */
19
20#include "mbedtls/build_info.h"
21
22#include "mbedtls/platform.h"
23
24#if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_FS_IO)
25#include "mbedtls/bignum.h"
26
27#include <stdio.h>
28#endif
29
30#if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_FS_IO)
31int main(void)
32{
33    mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_FS_IO not defined.\n");
34    mbedtls_exit(0);
35}
36#else
37
38
39int main(void)
40{
41    int ret = 1;
42    int exit_code = MBEDTLS_EXIT_FAILURE;
43    mbedtls_mpi E, P, Q, N, H, D, X, Y, Z;
44
45    mbedtls_mpi_init(&E); mbedtls_mpi_init(&P); mbedtls_mpi_init(&Q); mbedtls_mpi_init(&N);
46    mbedtls_mpi_init(&H); mbedtls_mpi_init(&D); mbedtls_mpi_init(&X); mbedtls_mpi_init(&Y);
47    mbedtls_mpi_init(&Z);
48
49    MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&P, 10, "2789"));
50    MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&Q, 10, "3203"));
51    MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&E, 10,  "257"));
52    MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&N, &P, &Q));
53
54    mbedtls_printf("\n  Public key:\n\n");
55    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  N = ", &N, 10, NULL));
56    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  E = ", &E, 10, NULL));
57
58    mbedtls_printf("\n  Private key:\n\n");
59    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  P = ", &P, 10, NULL));
60    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  Q = ", &Q, 10, NULL));
61
62#if defined(MBEDTLS_GENPRIME)
63    MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&P, &P, 1));
64    MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&Q, &Q, 1));
65    MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&H, &P, &Q));
66    MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(&D, &E, &H));
67
68    mbedtls_mpi_write_file("  D = E^-1 mod (P-1)*(Q-1) = ",
69                           &D, 10, NULL);
70#else
71    mbedtls_printf("\nTest skipped (MBEDTLS_GENPRIME not defined).\n\n");
72#endif
73    MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&X, 10, "55555"));
74    MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&Y, &X, &E, &N, NULL));
75    MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&Z, &Y, &D, &N, NULL));
76
77    mbedtls_printf("\n  RSA operation:\n\n");
78    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  X (plaintext)  = ", &X, 10, NULL));
79    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  Y (ciphertext) = X^E mod N = ", &Y, 10, NULL));
80    MBEDTLS_MPI_CHK(mbedtls_mpi_write_file("  Z (decrypted)  = Y^D mod N = ", &Z, 10, NULL));
81    mbedtls_printf("\n");
82
83    exit_code = MBEDTLS_EXIT_SUCCESS;
84
85cleanup:
86    mbedtls_mpi_free(&E); mbedtls_mpi_free(&P); mbedtls_mpi_free(&Q); mbedtls_mpi_free(&N);
87    mbedtls_mpi_free(&H); mbedtls_mpi_free(&D); mbedtls_mpi_free(&X); mbedtls_mpi_free(&Y);
88    mbedtls_mpi_free(&Z);
89
90    if (exit_code != MBEDTLS_EXIT_SUCCESS) {
91        mbedtls_printf("\nAn error occurred.\n");
92    }
93
94    mbedtls_exit(exit_code);
95}
96#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_FS_IO */
97