OpenSSL在EVP_VerifyFinal失败 [英] OpenSSL Fails at EVP_VerifyFinal

问题描述

经过几天的搜索互联网和openssl docs我打了墙。我尝试使用私钥签署邮件，然后使用公钥验证邮件的真实性。

After a few days of scouring the internet and openssl docs i've hit a wall. I'm attempting to sign a message with a private key, and then verify the authenticity of the message with a public key.

密钥生成代码：

    //Generate RSA Keys
    EVP_PKEY_CTX* KeyCtx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, NULL);
    if (KeyCtx == nullptr)
        return false;

    if (EVP_PKEY_keygen_init(KeyCtx) <= 0)
        return false;

    if (EVP_PKEY_CTX_set_rsa_keygen_bits(KeyCtx, RSA_KeyLen) <= 0)
        return false;

    if (EVP_PKEY_keygen(KeyCtx, &m_ServerKeyPair) <= 0)
        return false;

    if (EVP_PKEY_keygen(KeyCtx, &m_ClientKeyPair) <= 0)
        return false;

    //Write Keys to EVP_PKEYS for actual internal encryption,BIO mem is wiped after read so we need a new copy
    PEM_read_bio_PrivateKey(KeyToPrivBio(m_ServerKeyPair), &m_ServerPrivateKey, NULL, NULL);
    PEM_read_bio_PUBKEY(KeyToPubBio(m_ServerKeyPair), &m_ServerPublicKey, NULL, NULL);
    PEM_read_bio_PrivateKey(KeyToPrivBio(m_ClientKeyPair), &m_ClientPrivateKey, NULL, NULL);
    PEM_read_bio_PUBKEY(KeyToPubBio(m_ClientKeyPair), &m_ClientPublicKey, NULL, NULL);

RSA Sign：

bool SecureCrypto::RSASign(const unsigned char* Msg, size_t MsgLen,unsigned char** EncMsg, size_t& MsgLenEnc)
{
    EVP_PKEY_size(m_ServerPrivateKey);
    *EncMsg = (unsigned char*)malloc(EVP_PKEY_size(m_ServerPrivateKey));

    if (EVP_SignInit_ex(m_RSASignCtx, EVP_sha1(), 0) <= 0)
    {
        printf("Failed Init\n");
        return false;
    }

    if (EVP_SignUpdate(m_RSASignCtx, Msg, MsgLen) <= 0)
    {
        printf("Failed Update\n");
        return false;
    }

    if (EVP_SignFinal(m_RSASignCtx, *EncMsg, &MsgLenEnc, m_ServerPrivateKey) <=0)
    {
        printf("Failed Final Sign\n");
        return false;
    }
    EVP_MD_CTX_cleanup(m_RSASignCtx);

    return true;
}

RSA验证：

bool SecureCrypto::RSAVerifySignature(const unsigned char* MsgHash, size_t MsgHashLen,unsigned char* Msg, size_t MsgLen)
{
    if (EVP_VerifyInit(m_RSAVerifyCtx, EVP_sha1()) <= 0)
    {
        printf("Failed Verify Init\n");
        return false;
    }

    if (EVP_VerifyUpdate(m_RSAVerifyCtx, Msg, MsgLen) <= 0)
    {
        printf("Failed Verify \n");
        return false;
    }

    if (EVP_VerifyFinal(m_RSAVerifyCtx, MsgHash, MsgHashLen, m_ServerPublicKey)<=0);
    {
        printf("Failed Final Verify %s\n",ERR_error_string(ERR_get_error(),NULL));
        return false;
    }
    EVP_MD_CTX_cleanup(m_RSAVerifyCtx);
    return true;
}

密钥生成成功，我已经查看了它创建的密钥有效，并且格式为 ----- BEGIN PRIVATE KEY ----- ，一些大素数， ----- END PRIVATE KEY ----- 。符号似乎成功并返回一个散列。 EVP_Verify在最后一步EVP_VerifyFinal失败，ERR_error_string报告：

Key Generation is successful, and i have viewed the keys it creates they appear to be valid and are in the format -----BEGIN PRIVATE KEY-----, some large prime, -----END PRIVATE KEY-----. Sign appears to be successful and returns a hash. EVP_Verify fails on the last step EVP_VerifyFinal, ERR_error_string reports this:

error:00000000:lib(0):func(0):reason(0)

这显然没有帮助，有人可以指出我可能做错了。这是我第一次潜入openssl，所以这里可能有一些大问题。

Which is obviously not helpful, can someone please point out what i may be doing wrong. This is my first dive into openssl, so there may be some big issues here.

推荐答案

感谢JWW和indiv i解决我的问题，这是一个问题，我使用较旧的API，和不当的返回检查。解决方案：

Thanks to JWW and indiv i was able to solve my problem, it was an issue with me using older API's, and improper return checking. Solution:

bool SecureCrypto::RSASign(const unsigned char* Msg, size_t MsgLen,unsigned char** EncMsg, size_t* MsgLenEnc)
{
    if (EVP_DigestSignInit(m_RSASignCtx,NULL, EVP_sha256(), NULL,m_ServerPrivateKey) <= 0)
    {
        printf("Failed Init\n");
        return false;
    }

    if (EVP_DigestSignUpdate(m_RSASignCtx, Msg, MsgLen) <= 0)
    {
        printf("Failed Update\n");
        return false;
    }

    //Get Hash Size
    if (EVP_DigestSignFinal(m_RSASignCtx, NULL,MsgLenEnc) <=0)
    {
        printf("Failed Final Sign\n");
        return false;
    }

    //Allocate Space for hash
    *EncMsg = (unsigned char*)malloc(*MsgLenEnc);
    if (EVP_DigestSignFinal(m_RSASignCtx, *EncMsg, MsgLenEnc) <= 0)
    {
        printf("Failed Final Sign 1\n");
        return false;
    }

    EVP_MD_CTX_cleanup(m_RSASignCtx);

    return true;
}

bool SecureCrypto::RSAVerifySignature(const unsigned char* MsgHash, size_t MsgHashLen,unsigned char* Msg, size_t MsgLen,bool* Authentic)
{
    if (EVP_DigestVerifyInit(m_RSAVerifyCtx,NULL, EVP_sha256(),NULL,m_ServerPrivateKey) <= 0)
    {
        printf("Failed Verify Init\n");
        return false;
    }

    if (EVP_DigestVerifyUpdate(m_RSAVerifyCtx, Msg, MsgLen) <= 0)
    {
        printf("Failed Verify \n");
        return false;
    }

    int AuthStatus = EVP_DigestVerifyFinal(m_RSAVerifyCtx, (unsigned char*)MsgHash, MsgHashLen);

    if (AuthStatus==1)
    {
        //Message Authentic
        *Authentic = true;
        EVP_MD_CTX_cleanup(m_RSAVerifyCtx);
        return true;
    } else if(AuthStatus==0){
        //Message Not Authentic
        *Authentic = false;
        EVP_MD_CTX_cleanup(m_RSAVerifyCtx);
        return true; //Still did our job correctly
    } else{
        printf("Error\n");
        *Authentic = false;
        EVP_MD_CTX_cleanup(m_RSAVerifyCtx);
        return false;
    }
}

我不能相信我错过了这样一个明显的例子，谢谢对你帮助家伙，对不起我看起来那么愚蠢的哈哈。

I cant believe i missed such an obvious example, thanks for you help guys, sorry i looked so stupid lol.

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