[英]decryption of MS office
我正在对加密的MS Excel(使用SHA1进行RC4加密)进行解密,密码是已知的。在vs2010中,我可以对其进行正确解密,但是,我的程序必须在Win和linux下都可以工作。我不知道立即在Linux下获取加密密钥,这类似于在Win下:
int getEncrypKey(HCRYPTKEY *hKey, int blocknum)
{
//------------------------H0 = H(salt, password)-----
BYTE *pbSaltandPwdHash = NULL;
DWORD dwSaltandPwdLen = 0;
pbSaltandPwdHash = SHA1_2(psalt, 16, ppwd, strlen(pwd)/2, &dwSaltandPwdLen);
printf("SHA1 of SaltandPwd:\n");
for(DWORD i = 0 ; i < dwSaltandPwdLen ; i++) {
printf("%2.2x ",pbSaltandPwdHash[i]);
}
printf("\n");
//------------------------H0 = H(salt, password)-----
//------------------------Hfinal = H(H0, block)-----
HCRYPTHASH hHash1 = 0;
CryptCreateHash( hCryptProv, CALG_SHA1, 0, 0, &hHash1) ;
CryptHashData( hHash1, pbSaltandPwdHash, dwSaltandPwdLen, 0) ;
CryptHashData( hHash1, (unsigned char*)&blocknum, sizeof(blocknum), 0) ;
//------------------------Hfinal = H(H0, block)-----
CryptDeriveKey(hCryptProv, CALG_RC4, hHash1, 0x00280000, hKey);
if(hHash1 != 0) CryptDestroyHash(hHash1);
if(pbSaltandPwdHash != NULL) free(pbSaltandPwdHash);
return 0;
}
我知道如何在Linux下获得H0
,但我不知道如何获得hHash1
和hKey
。
这篇文章听起来像是在做同样的事情: 使用OpenSSL API实现Windows CryptoAPI CryptDeriveKey
在openssl中生成哈希的更一般的方法如下:
在您做任何事情之前:
#include <ssl/evp.h>
int main(int argc, char argv[]) // or in an "initialise" type function
{
OpenSSL_add_all_digests()
...
}
然后生成哈希( 省略错误检查 ):
const EVP_MD *digest;
EVP_MD_CTX context;
unsigned char hash[EVP_MAX_MD_SIZE];
unsigned int hash_len;
digest = EVP_get_digestbyname("sha1"); /* choose the hash type here */
EVP_MD_CTX_init(&context);
EVP_DigestInit_ex(&contxt, digest, NULL);
EVP_DigestUpdate(&context, pbSaltandPwdHash, dwSaltandPwdLen);
EVP_DigestUpdate(&context, &blocknum, sizeof(blocknum));
EVP_DigestFinal_ex(&context, hash, &hash_len);
EVP_MD_CTX_cleanup(&context);
/* Now use hash and hash_len as required */
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