demos/evp/aesgcm.c

   1 /* Simple AES GCM test program, uses the same NIST data used for the FIPS
   2  * self test but uses the application level EVP APIs.
   3  */
   4 #include <stdio.h>
   5 #include <openssl/bio.h>
   6 #include <openssl/evp.h>
   7
   8 /* AES-GCM test data from NIST public test vectors */
   9
  10 static const unsigned char gcm_key[] = {
  11         0xee,0xbc,0x1f,0x57,0x48,0x7f,0x51,0x92,0x1c,0x04,0x65,0x66,
  12         0x5f,0x8a,0xe6,0xd1,0x65,0x8b,0xb2,0x6d,0xe6,0xf8,0xa0,0x69,
  13         0xa3,0x52,0x02,0x93,0xa5,0x72,0x07,0x8f
  14 };
  15
  16 static const unsigned char gcm_iv[] = {
  17         0x99,0xaa,0x3e,0x68,0xed,0x81,0x73,0xa0,0xee,0xd0,0x66,0x84
  18 };
  19
  20 static const unsigned char gcm_pt[] = {
  21         0xf5,0x6e,0x87,0x05,0x5b,0xc3,0x2d,0x0e,0xeb,0x31,0xb2,0xea,
  22         0xcc,0x2b,0xf2,0xa5
  23 };
  24
  25 static const unsigned char gcm_aad[] = {
  26         0x4d,0x23,0xc3,0xce,0xc3,0x34,0xb4,0x9b,0xdb,0x37,0x0c,0x43,
  27         0x7f,0xec,0x78,0xde
  28 };
  29
  30 static const unsigned char gcm_ct[] = {
  31         0xf7,0x26,0x44,0x13,0xa8,0x4c,0x0e,0x7c,0xd5,0x36,0x86,0x7e,
  32         0xb9,0xf2,0x17,0x36
  33 };
  34
  35 static const unsigned char gcm_tag[] = {
  36         0x67,0xba,0x05,0x10,0x26,0x2a,0xe4,0x87,0xd7,0x37,0xee,0x62,
  37         0x98,0xf7,0x7e,0x0c
  38 };
  39
  40 void aes_gcm_encrypt(void)
  41         {
  42         EVP_CIPHER_CTX *ctx;
  43         int outlen, tmplen;
  44         unsigned char outbuf[1024];
  45         printf("AES GCM Encrypt:\n");
  46         printf("Plaintext:\n");
  47         BIO_dump_fp(stdout, gcm_pt, sizeof(gcm_pt));
  48         ctx = EVP_CIPHER_CTX_new();
  49         /* Set cipher type and mode */
  50         EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL);
  51         /* Set IV length if default 96 bits is not appropriate */
  52         EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, sizeof(gcm_iv), NULL);
  53         /* Initialise key and IV */
  54         EVP_EncryptInit_ex(ctx, NULL, NULL, gcm_key, gcm_iv);
  55         /* Zero or more calls to specify any AAD */
  56         EVP_EncryptUpdate(ctx, NULL, &outlen, gcm_aad, sizeof(gcm_aad));
  57         /* Encrypt plaintext */
  58         EVP_EncryptUpdate(ctx, outbuf, &outlen, gcm_pt, sizeof(gcm_pt));
  59         /* Output encrypted block */
  60         printf("Ciphertext:\n");
  61         BIO_dump_fp(stdout, outbuf, outlen);
  62         /* Finalise: note get no output for GCM */
  63         EVP_EncryptFinal_ex(ctx, outbuf, &outlen);
  64         /* Get tag */
  65         EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, 16, outbuf);
  66         /* Output tag */
  67         printf("Tag:\n");
  68         BIO_dump_fp(stdout, outbuf, 16);
  69         EVP_CIPHER_CTX_free(ctx);
  70         }
  71
  72 void aes_gcm_decrypt(void)
  73         {
  74         EVP_CIPHER_CTX *ctx;
  75         int outlen, tmplen, rv;
  76         unsigned char outbuf[1024];
  77         printf("AES GCM Derypt:\n");
  78         printf("Ciphertext:\n");
  79         BIO_dump_fp(stdout, gcm_ct, sizeof(gcm_ct));
  80         ctx = EVP_CIPHER_CTX_new();
  81         /* Select cipher */
  82         EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL);
  83         /* Set IV length, omit for 96 bits */
  84         EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, sizeof(gcm_iv), NULL);
  85         /* Specify key and IV */
  86         EVP_DecryptInit_ex(ctx, NULL, NULL, gcm_key, gcm_iv);
  87 #if 0
  88         /* Set expected tag value. A restriction in OpenSSL 1.0.1c and earlier
  89          * required the tag before any AAD or ciphertext */
  90         EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, sizeof(gcm_tag), gcm_tag);
  91 #endif
  92         /* Zero or more calls to specify any AAD */
  93         EVP_DecryptUpdate(ctx, NULL, &outlen, gcm_aad, sizeof(gcm_aad));
  94         /* Decrypt plaintext */
  95         EVP_DecryptUpdate(ctx, outbuf, &outlen, gcm_ct, sizeof(gcm_ct));
  96         /* Output decrypted block */
  97         printf("Plaintext:\n");
  98         BIO_dump_fp(stdout, outbuf, outlen);
  99         /* Set expected tag value. Works in OpenSSL 1.0.1d and later */
 100         EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, sizeof(gcm_tag), gcm_tag);
 101         /* Finalise: note get no output for GCM */
 102         rv = EVP_DecryptFinal_ex(ctx, outbuf, &outlen);
 103         /* Print out return value. If this is not successful authentication
 104          * failed and plaintext is not trustworthy.
 105          */
 106         printf("Tag Verify %s\n", rv > 0 ? "Successful!" : "Failed!");
 107         EVP_CIPHER_CTX_free(ctx);
 108         }
 109
 110 int main(int argc, char **argv)
 111         {
 112         aes_gcm_encrypt();
 113         aes_gcm_decrypt();
 114         }