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)
main(void)31 int 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
main(void)39 int 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
85 cleanup:
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