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下面的测试代码理论上应该给我 NIST 测试套件 58e2fccefa7e3061367f1d57a4e7455a 的结果，但是输出的十六进制转储会产生 9eeaed13b5f591104e2cda197fb99eeaed13b5f591104e2cda197fb9 吗？

#include <iostream>
#include <cstdio>
#include <polarssl/md.h>
#include <polarssl/entropy.h>
#include <polarssl/ctr_drbg.h>
#include <polarssl/cipher.h>
#include <cstdlib>
#include <fstream>


int main(int argc, char** argv) {
const cipher_info_t *cipher_info;
        cipher_info = cipher_info_from_string( "AES-128-GCM" );
        cipher_context_t cipher_ctx;
    cipher_init_ctx (&cipher_ctx,cipher_info);
        std::cout<<"KEYLEN"<<std::endl;
        std::cout<<cipher_info->key_length<<std::endl;
    std::cout<<"IVLEN"<<std::endl;
    std::cout<<cipher_info->iv_size<<std::endl;
unsigned char key[cipher_info->key_length/8];
    unsigned char iv[cipher_info->iv_size];
    memset(key,0x00,cipher_info->key_length/8);
    memset(iv,0x00,cipher_info->iv_size);
    unsigned char iBuffer[10];
    unsigned char oBuffer[1024];
    size_t ilen, olen;


std::ofstream oFile2;
    oFile2.open("testOut",std::ofstream::out | std::ofstream::trunc | std::ofstream::binary);

        cipher_setkey( &cipher_ctx,key,cipher_info->key_length,POLARSSL_ENCRYPT);
        cipher_set_iv( &cipher_ctx, iv, 16 );
        cipher_reset( &cipher_ctx );
    cipher_update( &cipher_ctx, iBuffer, sizeof(iBuffer), oBuffer, &olen );
    oFile2 << oBuffer;
    cipher_finish( &cipher_ctx, oBuffer, &olen );
    oFile2 << oBuffer;
    oFile2.close();
}

这是 nIST 测试：

Variable 
Value 
K  00000000000000000000000000000000
P
IV 000000000000000000000000
H 66e94bd4ef8a2c3b884cfa59ca342b2e
Yo 00000000000000000000000000000001
E ( K,Yo) 58e2fccefa7e3061367f1d57a4e7455a
len(A)||len(C)  00000000000000000000000000000000
GHASH (H,A,C) 00000000000000000000000000000000    
C
T 58e2fccefa7e3061367f1d57a4e7455a

（测试用例 1 http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/proposedmodes/gcm/gcm-revised-spec.pdf）

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1 回答 1

2

我可以看到两个直接的错误：

  1. 纯文本大小设置为 10 个字节，而不是根本没有字节 - 这使得密文太大并且身份验证标签不正确；
  2. IV 是 12 字节设置为 0 而不是 16 字节设置为 0 - 12 是 GCM 模式的默认值 - 这使得密文（如果有）和身份验证标签不正确。

这些问题在以下几行中：

unsigned char iBuffer[10];
...
cipher_update( &cipher_ctx, iBuffer, sizeof(iBuffer), oBuffer, &olen );

和

cipher_set_iv( &cipher_ctx, iv, 16 );

此外，API 似乎要求您使用...write_tag...方法单独检索标签。目前您只能看到 CTR 密文，而不是身份验证标签。

于 2015-05-13T09:39:00.290 回答