openssl学习之ccm,gcm 模式
openssl
传输层安全性/安全套接层及其加密库
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openssl中添加了对AES ccm 和gcm模式的支持。下面的内容主要是对这两个模式相关资料的收集以及整理。
一,CCM
CCM (counter with CBC-MAC)定义在分组长度为128位的加密算法中,如,AES 的分组长度为128。组成AES-CCM算法的关键组成是CTR工作模式以及CMAC认证算法。Wifi 的WPE协议中使用了AES-CCM。在HMAC中我们介绍CCM是属于一种E&M(认证并且加密),首先我们来看一下AES-CCM模式的输入输出。
首先介绍两个参数设置:
L:长度域,取值为2~8 ,openssl中缺省的为8。
M:tag的长度,合法的值为:4,6,8,10,12,14 和16。openssl中缺省的为12
key | 16,24,32 |
None | 15-L |
Message to authenticate and encrypt | len(Msg) |
Additional authenticated data | len(AAD) |
对附加数据长度有:0<= len(AAD)< 2^64;
/* 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
};
// 随机数,每次加密针对相同的KEY使用不同的NONCE。否则会破坏CCM模式的安全性(RFC3610)
static const unsigned char ccm_nonce[] = {
0x76,0x40,0x43,0xc4,0x94,0x60,0xb7
};
//附加数据
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
};
//plaintext 表示明文
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
};
//ciphertext 表示密文
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
};
//tag 表示tag数据
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*/
//输入输出需设置为NULL
EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_pt));
/* Zero or one call to specify any AAD */
//设置AAD,out参数需设置为NULL
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();
}
GCM基于并行化设计,因此可以提供高效的吞吐率和低成本、低时延。本质是消息在变形的CTR模式下加密,密文结果与密钥以及消息长度在GF(2^128)域上相乘,计算流程如下所示。其输入输出和CCM基本一致。CCM和GCM的具体计算过程可以参看《密码学与网络安全》第五版,书中有详细的介绍。FRC5288 中介绍了TLS1.2 中的GCM应用。下面贴出openssl中AES-GCM的实例。
/* Simple AES GCM 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-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();
}
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传输层安全性/安全套接层及其加密库
最近提交(Master分支:1 个月前 )
fd39d1c8
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/25095)
2 个月前
ae87c488
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/25095)
2 个月前
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