From 07a4ff79d23e45f1a45da717b7c1f41a5e1c7c0c Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Tue, 16 Oct 2012 23:03:45 +0000 Subject: [PATCH 1/1] add simple AES GCM code example --- demos/evp/aesgcm.c | 114 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 demos/evp/aesgcm.c diff --git a/demos/evp/aesgcm.c b/demos/evp/aesgcm.c new file mode 100644 index 0000000000..324d8a55b1 --- /dev/null +++ b/demos/evp/aesgcm.c @@ -0,0 +1,114 @@ +/* Simple AES GCM test program, uses the same NIST data used for the FIPS + * self test but uses the application level EVP APIs. + */ +#include +#include +#include + +/* AES-GCM test data from NIST public test vectors */ + +static const unsigned char gcm_key[] = { + 0xee,0xbc,0x1f,0x57,0x48,0x7f,0x51,0x92,0x1c,0x04,0x65,0x66, + 0x5f,0x8a,0xe6,0xd1,0x65,0x8b,0xb2,0x6d,0xe6,0xf8,0xa0,0x69, + 0xa3,0x52,0x02,0x93,0xa5,0x72,0x07,0x8f +}; + +static const unsigned char gcm_iv[] = { + 0x99,0xaa,0x3e,0x68,0xed,0x81,0x73,0xa0,0xee,0xd0,0x66,0x84 +}; + +static const unsigned char gcm_pt[] = { + 0xf5,0x6e,0x87,0x05,0x5b,0xc3,0x2d,0x0e,0xeb,0x31,0xb2,0xea, + 0xcc,0x2b,0xf2,0xa5 +}; + +static const unsigned char gcm_aad[] = { + 0x4d,0x23,0xc3,0xce,0xc3,0x34,0xb4,0x9b,0xdb,0x37,0x0c,0x43, + 0x7f,0xec,0x78,0xde +}; + +static const unsigned char gcm_ct[] = { + 0xf7,0x26,0x44,0x13,0xa8,0x4c,0x0e,0x7c,0xd5,0x36,0x86,0x7e, + 0xb9,0xf2,0x17,0x36 +}; + +static const unsigned char gcm_tag[] = { + 0x67,0xba,0x05,0x10,0x26,0x2a,0xe4,0x87,0xd7,0x37,0xee,0x62, + 0x98,0xf7,0x7e,0x0c +}; + +void aes_gcm_encrypt(void) + { + EVP_CIPHER_CTX *ctx; + int outlen, tmplen; + unsigned char outbuf[1024]; + printf("AES GCM Encrypt:\n"); + printf("Plaintext:\n"); + BIO_dump_fp(stdout, gcm_pt, sizeof(gcm_pt)); + ctx = EVP_CIPHER_CTX_new(); + /* Set cipher type and mode */ + EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL); + /* Set IV length if default 96 bits is not appropriate */ + EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, sizeof(gcm_iv), NULL); + /* Initialise key and IV */ + EVP_EncryptInit_ex(ctx, NULL, NULL, gcm_key, gcm_iv); + /* Zero or more calls to specify any AAD */ + EVP_EncryptUpdate(ctx, NULL, &outlen, gcm_aad, sizeof(gcm_aad)); + /* Encrypt plaintext */ + EVP_EncryptUpdate(ctx, outbuf, &outlen, gcm_pt, sizeof(gcm_pt)); + /* Output encrypted block */ + printf("Ciphertext:\n"); + BIO_dump_fp(stdout, outbuf, outlen); + /* Finalise: note get no output for GCM */ + EVP_EncryptFinal_ex(ctx, outbuf, &outlen); + /* Get tag */ + EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, 16, outbuf); + /* Output tag */ + printf("Tag:\n"); + BIO_dump_fp(stdout, outbuf, 16); + EVP_CIPHER_CTX_free(ctx); + } + +void aes_gcm_decrypt(void) + { + EVP_CIPHER_CTX *ctx; + int outlen, tmplen, rv; + unsigned char outbuf[1024]; + printf("AES GCM Derypt:\n"); + printf("Ciphertext:\n"); + BIO_dump_fp(stdout, gcm_ct, sizeof(gcm_ct)); + ctx = EVP_CIPHER_CTX_new(); + /* Select cipher */ + EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL); + /* Set IV length, omit for 96 bits */ + EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, sizeof(gcm_iv), NULL); + /* Specify key and IV */ + EVP_DecryptInit_ex(ctx, NULL, NULL, gcm_key, gcm_iv); +#if 0 + /* Set expected tag value. A restriction in OpenSSL 1.0.1c and earlier + * required the tag before any AAD or ciphertext */ + EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, sizeof(gcm_tag), gcm_tag); +#endif + /* Zero or more calls to specify any AAD */ + EVP_DecryptUpdate(ctx, NULL, &outlen, gcm_aad, sizeof(gcm_aad)); + /* Decrypt plaintext */ + EVP_DecryptUpdate(ctx, outbuf, &outlen, gcm_ct, sizeof(gcm_ct)); + /* Output decrypted block */ + printf("Plaintext:\n"); + BIO_dump_fp(stdout, outbuf, outlen); + /* Set expected tag value. Works in OpenSSL 1.0.1d and later */ + EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, sizeof(gcm_tag), gcm_tag); + /* Finalise: note get no output for GCM */ + rv = EVP_DecryptFinal_ex(ctx, outbuf, &outlen); + /* Print out return value. If this is not successful authentication + * failed and plaintext is not trustworthy. + */ + printf("Tag Verify %s\n", rv > 0 ? "Successful!" : "Failed!"); + EVP_CIPHER_CTX_free(ctx); + } + +int main(int argc, char **argv) + { + aes_gcm_encrypt(); + aes_gcm_decrypt(); + } -- 2.34.1