在c/c++中解決SHA1WithRSA/ras/X509的過程記錄

GOOSasha 8年前發布 | 46K 次閱讀 OpenSSL 加密解密 C/C++開發 C/C++

這里記錄了一種簡單的辦法，在遇到寫c/c++找不到答案時的最簡單找代碼辦法。

方法是：google找php怎么解決，大把的答案，然后看php源代碼是怎么用c實現的。

提出

我們server端在對接google play的時候，遇到了ras加密來驗證參數的實現，官方也沒有什么c的參考代碼，java和php的網上倒是能找到一堆。

java怎么解決

java的實現和本文要說的內容無關，只是隨帶一列：

public static boolean verify(String publicKey, byte[] data, String sign) throws Exception {

        // 解密由base64編碼的公鑰
        byte[] keyBytes = Base64.decodeBase64(publicKey);
        System.out.println(keyBytes.length);
        // 構造X509EncodedKeySpec對象
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);

        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");

        // 取公鑰匙對象
        PublicKey pubKey = keyFactory.generatePublic(keySpec);

        Signature signature = Signature.getInstance("SHA1WithRSA");
        signature.initVerify(pubKey);
        signature.update(data);

        // 驗證簽名是否正常
        return signature.verify(Base64.decodeBase64(sign));
    }

`php怎么解決`

php的實現比較多，隨便找了一個，沒有驗證過：

<?php
$public_key = file_get_contents(dirname(__FILE__).’/rsa_public_key.pem’);
$pkeyid = openssl_pkey_get_public($public_key);
$data = ‘abc’;
$sign = ‘WkMaSsx9Fbj9/YyjoM1X0SLYvaFbsz9VmMaxc42fXxamEEIj5AfqQLrygEZRq0gkLNT4heIwOiSWEAWbfD4imaERKk07ANXEtZJ9jPJvyvg70IVvaYMKAr7bX0dJXmYw4aHnkcWR1kz27Drr6fxPmchB9WCsRmi4VfhVoF1+HRFOp28nIVReGRcbwbW1/bcMisXbitirz9Wq396vY88GUSgbgNdhFXX/kzjRBTjnG+CIhXq4HPdOWovqtPhQoxmK55+V+vxNZk9OPPHHaN3vVswk062NOs2/05yNVObL+PWeg/m43buXYalmkrwEhemdGfjIdNEoSO2D4gikvm43cg==’;
$sign = base64_decode($sign);
if ($pkeyid) {
$verify = openssl_verify($data, $sign, $pkeyid, OPENSSL_ALGO_MD5);
openssl_free_key($pkeyid);
}
var_dump($verify);
?>

`找到代碼`

看到上面的php代碼，關鍵的幾個函數有：openssl_pkey_get_public openssl_verify

然后轉戰最新的php源代碼， https://github.com/php/php-src/blob/80f91fd9d513b83ca88345a2a8c76523e0164789/ext/openssl/openssl.c 。

別問為什么可以定位到這個文件的，github可以直接搜一個庫里的源文件。

忽略一切以zend、zval開頭的邏輯，直接找上面關鍵的函數。

于是就找到了關鍵的頭文件:

/* OpenSSL includes */
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#include <openssl/dh.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/crypto.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/conf.h>
#include <openssl/rand.h>
#include <openssl/ssl.h>
#include <openssl/pkcs12.h>

關鍵的一行key生成代碼:

key = PEM_read_bio_PrivateKey(in, NULL,NULL, passphrase);

關鍵的核心邏輯:

EVP_VerifyInit (&md_ctx, mdtype);
    EVP_VerifyUpdate (&md_ctx, data, data_len);
    err = EVP_VerifyFinal(&md_ctx, (unsigned char *)signature, (unsigned int)signature_len, pkey);
    EVP_MD_CTX_cleanup(&md_ctx);

    if (keyresource == NULL) {
        EVP_PKEY_free(pkey);
    }

這么些核心代碼都找到了，還不會抄嗎？

`最終解決`

通過上面的過程，進行自己的組裝，已經再簡單不過了，為了讓寫c/c++的同學們快速得到google play的rsa驗證代碼，特別貼一下：

int verifiedByRsaPublicKey(const string& publicKey, const string& signature, char* message) {
    char *chPublicKey = const_cast<char *>(publicKey.c_str());

    BIO* mem_bio = NULL;
    if ((mem_bio = BIO_new_mem_buf(chPublicKey, -1)) == NULL) {        //從字符串讀取RSA公鑰
        BIO_free(mem_bio);
        return -3;
    }
    EVP_PKEY *publicRsa = PEM_read_bio_PUBKEY(mem_bio, NULL, NULL, NULL);
    unsigned int slen = signature.length();

    EVP_MD_CTX md_ctx;
    EVP_VerifyInit(&md_ctx, EVP_sha1());
    EVP_VerifyUpdate(&md_ctx, message, strlen(message));
    int err = EVP_VerifyFinal(&md_ctx, (unsigned char*) signature.data(), slen, publicRsa);
    EVP_MD_CTX_cleanup(&md_ctx);
    EVP_PKEY_free(publicRsa);
    return err;
}

`結論`

通過php的解決方案去找到php的實現，是寫c/c++同學們不可不學的一招。

`EOF`

`English Version`

`a story about SHA1WithRSA/ras/X509 with c/c++`

This is a simple solution when you do not know how to develop with c/c++.

The solution is,it will have lots of answer ho to do with php in Google,and then look up the desgin in the source codes of php.

`Question`

We need to verify the parameters by RSA when we devlop the Google Play apps.There is not any reference codes with c/c++.The java or php example are too many in internet.

`How to resolve in java`

It no connection with what we are talking about.Just BTW:

public static boolean verify(String publicKey, byte[] data, String sign) throws Exception {

        // 解密由base64編碼的公鑰
        byte[] keyBytes = Base64.decodeBase64(publicKey);
        System.out.println(keyBytes.length);
        // 構造X509EncodedKeySpec對象
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);

        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");

        // 取公鑰匙對象
        PublicKey pubKey = keyFactory.generatePublic(keySpec);

        Signature signature = Signature.getInstance("SHA1WithRSA");
        signature.initVerify(pubKey);
        signature.update(data);

        // 驗證簽名是否正常
        return signature.verify(Base64.decodeBase64(sign));
    }

`How to resolve in php`

There are too many php examples.Find one without checking:

<?php
$public_key = file_get_contents(dirname(__FILE__).’/rsa_public_key.pem’);
$pkeyid = openssl_pkey_get_public($public_key);
$data = ‘abc’;
$sign = ‘WkMaSsx9Fbj9/YyjoM1X0SLYvaFbsz9VmMaxc42fXxamEEIj5AfqQLrygEZRq0gkLNT4heIwOiSWEAWbfD4imaERKk07ANXEtZJ9jPJvyvg70IVvaYMKAr7bX0dJXmYw4aHnkcWR1kz27Drr6fxPmchB9WCsRmi4VfhVoF1+HRFOp28nIVReGRcbwbW1/bcMisXbitirz9Wq396vY88GUSgbgNdhFXX/kzjRBTjnG+CIhXq4HPdOWovqtPhQoxmK55+V+vxNZk9OPPHHaN3vVswk062NOs2/05yNVObL+PWeg/m43buXYalmkrwEhemdGfjIdNEoSO2D4gikvm43cg==’;
$sign = base64_decode($sign);
if ($pkeyid) {
$verify = openssl_verify($data, $sign, $pkeyid, OPENSSL_ALGO_MD5);
openssl_free_key($pkeyid);
}
var_dump($verify);
?>

`Find the codes`

The key functions are openssl_pkey_get_public and openssl_verify in the codes above mentioned.

Go to the newest php source codes, https://github.com/php/php-src/blob/80f91fd9d513b83ca88345a2a8c76523e0164789/ext/openssl/openssl.c

Dont ask me how to find the file.You can search the file in a project at Github.

Ignore all the codes start with zval and zend.Go to the codes which include the key functions.

And then there is the key header file:

/* OpenSSL includes */
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#include <openssl/dh.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/crypto.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/conf.h>
#include <openssl/rand.h>
#include <openssl/ssl.h>
#include <openssl/pkcs12.h>

The key codes generated pkey:

key = PEM_read_bio_PrivateKey(in, NULL,NULL, passphrase);

The core logic:

EVP_VerifyInit (&md_ctx, mdtype);
    EVP_VerifyUpdate (&md_ctx, data, data_len);
    err = EVP_VerifyFinal(&md_ctx, (unsigned char *)signature, (unsigned int)signature_len, pkey);
    EVP_MD_CTX_cleanup(&md_ctx);

    if (keyresource == NULL) {
        EVP_PKEY_free(pkey);
    }

All of the codes are ready,cant you copy?

`Final`

It is easy to merge the codes above mentioned.

To get the codes faster for any other people,there are the codes about Google play Ras verifying:

int verifiedByRsaPublicKey(const string& publicKey, const string& signature, char* message) {
    char *chPublicKey = const_cast<char *>(publicKey.c_str());

    BIO* mem_bio = NULL;
    if ((mem_bio = BIO_new_mem_buf(chPublicKey, -1)) == NULL) {        //從字符串讀取RSA公鑰
        BIO_free(mem_bio);
        return -3;
    }
    EVP_PKEY *publicRsa = PEM_read_bio_PUBKEY(mem_bio, NULL, NULL, NULL);
    unsigned int slen = signature.length();

    EVP_MD_CTX md_ctx;
    EVP_VerifyInit(&md_ctx, EVP_sha1());
    EVP_VerifyUpdate(&md_ctx, message, strlen(message));
    int err = EVP_VerifyFinal(&md_ctx, (unsigned char*) signature.data(), slen, publicRsa);
    EVP_MD_CTX_cleanup(&md_ctx);
    EVP_PKEY_free(publicRsa);
    return err;
}

`Conclusion`

Is is a good solution for c/c++ developer.You can find the answer in php at first,go to see the c source codes of php at last.

原創文章如轉載，請注明：轉載自五四陳科學院[ http://www.54chen.com ]

來自： http://2014.54chen.com/blog/2016/05/25/a-story-about-sha1withrsa-slash-ras-slash-x509-with-c-slash-c-plus-plus/

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OpenSSL 加密解密 C/C++開發 C/C++