/* Simple AES CCM test program, uses the same NIST data used for the FIPS
 * self test but uses the application level EVP APIs.
 */
#include <stdio.h>
#include <openssl/bio.h>
#include <openssl/evp.h>

/* AES-CCM test data from NIST public test vectors */

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
};

static const unsigned char ccm_nonce[] = {
	0x76,0x40,0x43,0xc4,0x94,0x60,0xb7
};

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
};

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
};

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
};

static const unsigned char ccm_tag[] = {
	0x2d,0xd6,0xef,0x1c,0x45,0xd4,0xcc,0xb7,0x23,0xdc,0x07,0x44,
	0x14,0xdb,0x50,0x6d
};

void aes_ccm_encrypt(void)
	{
	EVP_CIPHER_CTX *ctx;
	int outlen, tmplen;
	unsigned char outbuf[1024];
	printf("AES CCM Encrypt:\n");
	printf("Plaintext:\n");
	BIO_dump_fp(stdout, ccm_pt, sizeof(ccm_pt));
	ctx = EVP_CIPHER_CTX_new();
	/* Set cipher type and mode */
	EVP_EncryptInit_ex(ctx, EVP_aes_192_ccm(), NULL, NULL, NULL);
	/* Set nonce length if default 96 bits is not appropriate */
	EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_IVLEN, sizeof(ccm_nonce), NULL);
	/* Set tag length */
	EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_TAG, sizeof(ccm_tag), NULL);
	/* Initialise key and IV */
	EVP_EncryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce);
	/* Set plaintext length: only needed if AAD is used */
	EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_pt));
	/* Zero or one call to specify any AAD */
	EVP_EncryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata));
	/* Encrypt plaintext: can only be called once */
	EVP_EncryptUpdate(ctx, outbuf, &outlen, ccm_pt, sizeof(ccm_pt));
	/* Output encrypted block */
	printf("Ciphertext:\n");
	BIO_dump_fp(stdout, outbuf, outlen);
	/* Finalise: note get no output for CCM */
	EVP_EncryptFinal_ex(ctx, outbuf, &outlen);
	/* Get tag */
	EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_GET_TAG, 16, outbuf);
	/* Output tag */
	printf("Tag:\n");
	BIO_dump_fp(stdout, outbuf, 16);
	EVP_CIPHER_CTX_free(ctx);
	}

void aes_ccm_decrypt(void)
	{
	EVP_CIPHER_CTX *ctx;
	int outlen, tmplen, rv;
	unsigned char outbuf[1024];
	printf("AES CCM Derypt:\n");
	printf("Ciphertext:\n");
	BIO_dump_fp(stdout, ccm_ct, sizeof(ccm_ct));
	ctx = EVP_CIPHER_CTX_new();
	/* Select cipher */
	EVP_DecryptInit_ex(ctx, EVP_aes_192_ccm(), NULL, NULL, NULL);
	/* Set nonce length, omit for 96 bits */
	EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_IVLEN, sizeof(ccm_nonce), NULL);
	/* Set expected tag value */
	EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_TAG,
					sizeof(ccm_tag), (void *)ccm_tag);
	/* Specify key and IV */
	EVP_DecryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce);
	/* Set ciphertext length: only needed if we have AAD */
	EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_ct));
	/* Zero or one call to specify any AAD */
	EVP_DecryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata));
	/* 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("Plaintext:\n");
		BIO_dump_fp(stdout, outbuf, outlen);
		}
	else
		printf("Plaintext not available: tag verify failed.\n");
	EVP_CIPHER_CTX_free(ctx);
	}

int main(int argc, char **argv)
	{
	aes_ccm_encrypt();
	aes_ccm_decrypt();
	}