1 files changed, 153 insertions, 0 deletions
diff --git a/programs/pkey/pk_decrypt.c b/programs/pkey/pk_decrypt.c
new file mode 100644
index 00000000000..b8f7943d623
--- /dev/null
+++ b/programs/pkey/pk_decrypt.c
@@ -0,0 +1,153 @@
+/*
+ *  Public key-based simple decryption program
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#include "mbedtls/build_info.h"
+
+#include "mbedtls/platform.h"
+
+#if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_PK_PARSE_C) && \
+    defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C)
+#include "mbedtls/error.h"
+#include "mbedtls/pk.h"
+#include "mbedtls/entropy.h"
+#include "mbedtls/ctr_drbg.h"
+
+#include <stdio.h>
+#include <string.h>
+#endif
+
+#if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_PK_PARSE_C) ||  \
+    !defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_ENTROPY_C) || \
+    !defined(MBEDTLS_CTR_DRBG_C)
+int main(void)
+{
+    mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_PK_PARSE_C and/or "
+                   "MBEDTLS_FS_IO and/or MBEDTLS_ENTROPY_C and/or "
+                   "MBEDTLS_CTR_DRBG_C not defined.\n");
+    mbedtls_exit(0);
+}
+#else
+
+
+int main(int argc, char *argv[])
+{
+    FILE *f;
+    int ret = 1;
+    unsigned c;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
+    size_t i, olen = 0;
+    mbedtls_pk_context pk;
+    mbedtls_entropy_context entropy;
+    mbedtls_ctr_drbg_context ctr_drbg;
+    unsigned char result[1024];
+    unsigned char buf[512];
+    const char *pers = "mbedtls_pk_decrypt";
+    ((void) argv);
+
+    mbedtls_pk_init(&pk);
+    mbedtls_entropy_init(&entropy);
+    mbedtls_ctr_drbg_init(&ctr_drbg);
+
+    memset(result, 0, sizeof(result));
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    psa_status_t status = psa_crypto_init();
+    if (status != PSA_SUCCESS) {
+        mbedtls_fprintf(stderr, "Failed to initialize PSA Crypto implementation: %d\n",
+                        (int) status);
+        goto exit;
+    }
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+    if (argc != 2) {
+        mbedtls_printf("usage: mbedtls_pk_decrypt <key_file>\n");
+
+#if defined(_WIN32)
+        mbedtls_printf("\n");
+#endif
+
+        goto exit;
+    }
+
+    mbedtls_printf("\n  . Seeding the random number generator...");
+    fflush(stdout);
+
+    if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
+                                     &entropy, (const unsigned char *) pers,
+                                     strlen(pers))) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_ctr_drbg_seed returned -0x%04x\n",
+                       (unsigned int) -ret);
+        goto exit;
+    }
+
+    mbedtls_printf("\n  . Reading private key from '%s'", argv[1]);
+    fflush(stdout);
+
+    if ((ret = mbedtls_pk_parse_keyfile(&pk, argv[1], "",
+                                        mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_pk_parse_keyfile returned -0x%04x\n",
+                       (unsigned int) -ret);
+        goto exit;
+    }
+
+    /*
+     * Extract the RSA encrypted value from the text file
+     */
+    if ((f = fopen("result-enc.txt", "rb")) == NULL) {
+        mbedtls_printf("\n  ! Could not open %s\n\n", "result-enc.txt");
+        ret = 1;
+        goto exit;
+    }
+
+    i = 0;
+    while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
+           i < (int) sizeof(buf)) {
+        buf[i++] = (unsigned char) c;
+    }
+
+    fclose(f);
+
+    /*
+     * Decrypt the encrypted RSA data and print the result.
+     */
+    mbedtls_printf("\n  . Decrypting the encrypted data");
+    fflush(stdout);
+
+    if ((ret = mbedtls_pk_decrypt(&pk, buf, i, result, &olen, sizeof(result),
+                                  mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
+        mbedtls_printf(" failed\n  ! mbedtls_pk_decrypt returned -0x%04x\n",
+                       (unsigned int) -ret);
+        goto exit;
+    }
+
+    mbedtls_printf("\n  . OK\n\n");
+
+    mbedtls_printf("The decrypted result is: '%s'\n\n", result);
+
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
+exit:
+
+    mbedtls_pk_free(&pk);
+    mbedtls_entropy_free(&entropy);
+    mbedtls_ctr_drbg_free(&ctr_drbg);
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    mbedtls_psa_crypto_free();
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+#if defined(MBEDTLS_ERROR_C)
+    if (exit_code != MBEDTLS_EXIT_SUCCESS) {
+        mbedtls_strerror(ret, (char *) buf, sizeof(buf));
+        mbedtls_printf("  !  Last error was: %s\n", buf);
+    }
+#endif
+
+    mbedtls_exit(exit_code);
+}
+#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
+          MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */