/* * Copyright 2013-2023 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 */ /* * Simple AES CCM authenticated encryption with additional data (AEAD) * demonstration program. */ #include #include #include #include #include /* AES-CCM test data obtained from NIST public test vectors */ /* AES key */ static const unsigned char ccm_key[] = { 0xce, 0xb0, 0x09, 0xae, 0xa4, 0x45, 0x44, 0x51, 0xfe, 0xad, 0xf0, 0xe6, 0xb3, 0x6f, 0x45, 0x55, 0x5d, 0xd0, 0x47, 0x23, 0xba, 0xa4, 0x48, 0xe8 }; /* Unique nonce to be used for this message */ static const unsigned char ccm_nonce[] = { 0x76, 0x40, 0x43, 0xc4, 0x94, 0x60, 0xb7 }; /* * Example of Additional Authenticated Data (AAD), i.e. unencrypted data * which can be authenticated using the generated Tag value. */ static const unsigned char ccm_adata[] = { 0x6e, 0x80, 0xdd, 0x7f, 0x1b, 0xad, 0xf3, 0xa1, 0xc9, 0xab, 0x25, 0xc7, 0x5f, 0x10, 0xbd, 0xe7, 0x8c, 0x23, 0xfa, 0x0e, 0xb8, 0xf9, 0xaa, 0xa5, 0x3a, 0xde, 0xfb, 0xf4, 0xcb, 0xf7, 0x8f, 0xe4 }; /* Example plaintext to encrypt */ static const unsigned char ccm_pt[] = { 0xc8, 0xd2, 0x75, 0xf9, 0x19, 0xe1, 0x7d, 0x7f, 0xe6, 0x9c, 0x2a, 0x1f, 0x58, 0x93, 0x9d, 0xfe, 0x4d, 0x40, 0x37, 0x91, 0xb5, 0xdf, 0x13, 0x10 }; /* Expected ciphertext value */ static const unsigned char ccm_ct[] = { 0x8a, 0x0f, 0x3d, 0x82, 0x29, 0xe4, 0x8e, 0x74, 0x87, 0xfd, 0x95, 0xa2, 0x8a, 0xd3, 0x92, 0xc8, 0x0b, 0x36, 0x81, 0xd4, 0xfb, 0xc7, 0xbb, 0xfd }; /* Expected AEAD Tag value */ static const unsigned char ccm_tag[] = { 0x2d, 0xd6, 0xef, 0x1c, 0x45, 0xd4, 0xcc, 0xb7, 0x23, 0xdc, 0x07, 0x44, 0x14, 0xdb, 0x50, 0x6d }; /* * A library context and property query can be used to select & filter * algorithm implementations. If they are NULL then the default library * context and properties are used. */ static OSSL_LIB_CTX *libctx = NULL; static const char *propq = NULL; static int aes_ccm_encrypt(void) { int ret = 0; EVP_CIPHER_CTX *ctx; EVP_CIPHER *cipher = NULL; int outlen, tmplen; size_t ccm_nonce_len = sizeof(ccm_nonce); size_t ccm_tag_len = sizeof(ccm_tag); unsigned char outbuf[1024]; unsigned char outtag[16]; OSSL_PARAM params[3] = { OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END }; printf("AES CCM Encrypt:\n"); printf("Plaintext:\n"); BIO_dump_fp(stdout, ccm_pt, sizeof(ccm_pt)); /* Create a context for the encrypt operation */ if ((ctx = EVP_CIPHER_CTX_new()) == NULL) goto err; /* Fetch the cipher implementation */ if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL) goto err; /* Set nonce length if default 96 bits is not appropriate */ params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN, &ccm_nonce_len); /* Set tag length */ params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG, NULL, ccm_tag_len); /* * Initialise encrypt operation with the cipher & mode, * nonce length and tag length parameters. */ if (!EVP_EncryptInit_ex2(ctx, cipher, NULL, NULL, params)) goto err; /* Initialise key and nonce */ if (!EVP_EncryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce)) goto err; /* Set plaintext length: only needed if AAD is used */ if (!EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_pt))) goto err; /* Zero or one call to specify any AAD */ if (!EVP_EncryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata))) goto err; /* Encrypt plaintext: can only be called once */ if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, ccm_pt, sizeof(ccm_pt))) goto err; /* Output encrypted block */ printf("Ciphertext:\n"); BIO_dump_fp(stdout, outbuf, outlen); /* Finalise: note get no output for CCM */ if (!EVP_EncryptFinal_ex(ctx, NULL, &tmplen)) goto err; /* Get tag */ params[0] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG, outtag, ccm_tag_len); params[1] = OSSL_PARAM_construct_end(); if (!EVP_CIPHER_CTX_get_params(ctx, params)) goto err; /* Output tag */ printf("Tag:\n"); BIO_dump_fp(stdout, outtag, ccm_tag_len); ret = 1; err: if (!ret) ERR_print_errors_fp(stderr); EVP_CIPHER_free(cipher); EVP_CIPHER_CTX_free(ctx); return ret; } static int aes_ccm_decrypt(void) { int ret = 0; EVP_CIPHER_CTX *ctx; EVP_CIPHER *cipher = NULL; int outlen, rv; unsigned char outbuf[1024]; size_t ccm_nonce_len = sizeof(ccm_nonce); OSSL_PARAM params[3] = { OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END }; printf("AES CCM Decrypt:\n"); printf("Ciphertext:\n"); BIO_dump_fp(stdout, ccm_ct, sizeof(ccm_ct)); if ((ctx = EVP_CIPHER_CTX_new()) == NULL) goto err; /* Fetch the cipher implementation */ if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL) goto err; /* Set nonce length if default 96 bits is not appropriate */ params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN, &ccm_nonce_len); /* Set tag length */ params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG, (unsigned char *)ccm_tag, sizeof(ccm_tag)); /* * Initialise decrypt operation with the cipher & mode, * nonce length and expected tag parameters. */ if (!EVP_DecryptInit_ex2(ctx, cipher, NULL, NULL, params)) goto err; /* Specify key and IV */ if (!EVP_DecryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce)) goto err; /* Set ciphertext length: only needed if we have AAD */ if (!EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_ct))) goto err; /* Zero or one call to specify any AAD */ if (!EVP_DecryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata))) goto err; /* Decrypt plaintext, verify tag: can only be called once */ rv = EVP_DecryptUpdate(ctx, outbuf, &outlen, ccm_ct, sizeof(ccm_ct)); /* Output decrypted block: if tag verify failed we get nothing */ if (rv > 0) { printf("Tag verify successful!\nPlaintext:\n"); BIO_dump_fp(stdout, outbuf, outlen); } else { printf("Tag verify failed!\nPlaintext not available\n"); goto err; } ret = 1; err: if (!ret) ERR_print_errors_fp(stderr); EVP_CIPHER_free(cipher); EVP_CIPHER_CTX_free(ctx); return ret; } int main(int argc, char **argv) { if (!aes_ccm_encrypt()) return EXIT_FAILURE; if (!aes_ccm_decrypt()) return EXIT_FAILURE; return EXIT_SUCCESS; }