diff options
Diffstat (limited to 'demos/encrypt/rsa_encrypt.c')
| -rw-r--r-- | demos/encrypt/rsa_encrypt.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/demos/encrypt/rsa_encrypt.c b/demos/encrypt/rsa_encrypt.c new file mode 100644 index 0000000000..e3d8981e41 --- /dev/null +++ b/demos/encrypt/rsa_encrypt.c @@ -0,0 +1,243 @@ +/*- + * Copyright 2021 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the Apache License 2.0 (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +/* + * An example that uses EVP_PKEY_encrypt and EVP_PKEY_decrypt methods + * to encrypt and decrypt data using an RSA keypair. + * RSA encryption produces different encrypted output each time it is run, + * hence this is not a known answer test. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <openssl/err.h> +#include <openssl/evp.h> +#include <openssl/decoder.h> +#include <openssl/core_names.h> +#include "rsa_encrypt.h" + +/* Input data to encrypt */ +static const unsigned char msg[] = + "To be, or not to be, that is the question,\n" + "Whether tis nobler in the minde to suffer\n" + "The slings and arrowes of outragious fortune,\n" + "Or to take Armes again in a sea of troubles"; + +/* + * For do_encrypt(), load an RSA public key from pub_key_der[]. + * For do_decrypt(), load an RSA private key from priv_key_der[]. + */ +static EVP_PKEY *get_key(OSSL_LIB_CTX *libctx, const char *propq, int public) +{ + OSSL_DECODER_CTX *dctx = NULL; + EVP_PKEY *pkey = NULL; + int selection; + const unsigned char *data; + size_t data_len; + + if (public) { + selection = EVP_PKEY_PUBLIC_KEY; + data = pub_key_der; + data_len = sizeof(pub_key_der); + } else { + selection = EVP_PKEY_KEYPAIR; + data = priv_key_der; + data_len = sizeof(priv_key_der); + } + dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, "DER", NULL, "RSA", + selection, libctx, propq); + (void)OSSL_DECODER_from_data(dctx, &data, &data_len); + OSSL_DECODER_CTX_free(dctx); + return pkey; +} + +/* Set optional parameters for RSA OAEP Padding */ +static void set_optional_params(OSSL_PARAM *p, const char *propq) +{ + static unsigned char label[] = "label"; + + /* "pkcs1" is used by default if the padding mode is not set */ + *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ASYM_CIPHER_PARAM_PAD_MODE, + OSSL_PKEY_RSA_PAD_MODE_OAEP, 0); + /* No oaep_label is used if this is not set */ + *p++ = OSSL_PARAM_construct_octet_string(OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL, + label, sizeof(label)); + /* "SHA1" is used if this is not set */ + *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST, + "SHA256", 0); + /* + * If a non default property query needs to be specified when fetching the + * OAEP digest then it needs to be specified here. + */ + if (propq != NULL) + *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS, + (char *)propq, 0); + + /* + * OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST and + * OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS can also be optionally added + * here if the MGF1 digest differs from the OAEP digest. + */ + + *p = OSSL_PARAM_construct_end(); +} + +/* + * The length of the input data that can be encrypted is limited by the + * RSA key length minus some additional bytes that depends on the padding mode. + * + */ +static int do_encrypt(OSSL_LIB_CTX *libctx, + const unsigned char *in, size_t in_len, + unsigned char **out, size_t *out_len) +{ + int ret = 0, public = 1; + size_t buf_len = 0; + unsigned char *buf = NULL; + const char *propq = NULL; + EVP_PKEY_CTX *ctx = NULL; + EVP_PKEY *pub_key = NULL; + OSSL_PARAM params[5]; + + /* Get public key */ + pub_key = get_key(libctx, propq, public); + if (pub_key == NULL) { + fprintf(stderr, "Get public key failed.\n"); + goto cleanup; + } + ctx = EVP_PKEY_CTX_new_from_pkey(libctx, pub_key, propq); + if (ctx == NULL) { + fprintf(stderr, "EVP_PKEY_CTX_new_from_pkey() failed.\n"); + goto cleanup; + } + set_optional_params(params, propq); + /* If no optional parameters are required then NULL can be passed */ + if (EVP_PKEY_encrypt_init_ex(ctx, params) <= 0) { + fprintf(stderr, "EVP_PKEY_encrypt_init_ex() failed.\n"); + goto cleanup; + } + /* Calculate the size required to hold the encrypted data */ + if (EVP_PKEY_encrypt(ctx, NULL, &buf_len, in, in_len) <= 0) { + fprintf(stderr, "EVP_PKEY_encrypt() failed.\n"); + goto cleanup; + } + buf = OPENSSL_zalloc(buf_len); + if (buf == NULL) { + fprintf(stderr, "Malloc failed.\n"); + goto cleanup; + } + if (EVP_PKEY_encrypt(ctx, buf, &buf_len, in, in_len) <= 0) { + fprintf(stderr, "EVP_PKEY_encrypt() failed.\n"); + goto cleanup; + } + *out_len = buf_len; + *out = buf; + fprintf(stdout, "Encrypted:\n"); + BIO_dump_indent_fp(stdout, buf, buf_len, 2); + fprintf(stdout, "\n"); + ret = 1; + +cleanup: + if (!ret) + OPENSSL_free(buf); + EVP_PKEY_free(pub_key); + EVP_PKEY_CTX_free(ctx); + return ret; +} + +static int do_decrypt(OSSL_LIB_CTX *libctx, const char *in, size_t in_len, + unsigned char **out, size_t *out_len) +{ + int ret = 0, public = 0; + size_t buf_len = 0; + unsigned char *buf = NULL; + const char *propq = NULL; + EVP_PKEY_CTX *ctx = NULL; + EVP_PKEY *priv_key = NULL; + OSSL_PARAM params[5]; + + /* Get private key */ + priv_key = get_key(libctx, propq, public); + if (priv_key == NULL) { + fprintf(stderr, "Get private key failed.\n"); + goto cleanup; + } + ctx = EVP_PKEY_CTX_new_from_pkey(libctx, priv_key, propq); + if (ctx == NULL) { + fprintf(stderr, "EVP_PKEY_CTX_new_from_pkey() failed.\n"); + goto cleanup; + } + + /* The parameters used for encryption must also be used for decryption */ + set_optional_params(params, propq); + /* If no optional parameters are required then NULL can be passed */ + if (EVP_PKEY_decrypt_init_ex(ctx, params) <= 0) { + fprintf(stderr, "EVP_PKEY_decrypt_init_ex() failed.\n"); + goto cleanup; + } + /* Calculate the size required to hold the decrypted data */ + if (EVP_PKEY_decrypt(ctx, NULL, &buf_len, in, in_len) <= 0) { + fprintf(stderr, "EVP_PKEY_decrypt() failed.\n"); + goto cleanup; + } + buf = OPENSSL_zalloc(buf_len); + if (buf == NULL) { + fprintf(stderr, "Malloc failed.\n"); + goto cleanup; + } + if (EVP_PKEY_decrypt(ctx, buf, &buf_len, in, in_len) <= 0) { + fprintf(stderr, "EVP_PKEY_decrypt() failed.\n"); + goto cleanup; + } + *out_len = buf_len; + *out = buf; + fprintf(stdout, "Decrypted:\n"); + BIO_dump_indent_fp(stdout, buf, buf_len, 2); + fprintf(stdout, "\n"); + ret = 1; + +cleanup: + if (!ret) + OPENSSL_free(buf); + EVP_PKEY_free(priv_key); + EVP_PKEY_CTX_free(ctx); + return ret; +} + +int main(void) +{ + int ret = EXIT_FAILURE; + size_t msg_len = sizeof(msg) - 1; + size_t encrypted_len = 0, decrypted_len = 0; + unsigned char *encrypted = NULL, *decrypted = NULL; + OSSL_LIB_CTX *libctx = NULL; + + if (!do_encrypt(libctx, msg, msg_len, &encrypted, &encrypted_len)) { + fprintf(stderr, "encryption failed.\n"); + goto cleanup; + } + if (!do_decrypt(libctx, encrypted, encrypted_len, + &decrypted, &decrypted_len)) { + fprintf(stderr, "decryption failed.\n"); + goto cleanup; + } + if (CRYPTO_memcmp(msg, decrypted, decrypted_len) != 0) { + fprintf(stderr, "Decrypted data does not match expected value\n"); + goto cleanup; + } + ret = EXIT_SUCCESS; + +cleanup: + OPENSSL_free(decrypted); + OPENSSL_free(encrypted); + OSSL_LIB_CTX_free(libctx); + if (ret != EXIT_SUCCESS) + ERR_print_errors_fp(stderr); + return ret; +} |