x509中的char缓冲区的EVP_PKEY(PKCS7) [英] EVP_PKEY from char buffer in x509 (PKCS7)

问题描述

我有一个DER证书，可以从中获取未签名的char缓冲区中的公钥，如下所示，这是正确的获取方法吗?

I have a DER certificate from which I am retrieving the Public key in unsigned char buffer as following, is it the right way of getting?

pStoredPublicKey = X509_get_pubkey(x509);
if(pStoredPublicKey == NULL)
{
        printf(": publicKey is NULL\n");
}
if(pStoredPublicKey->type == EVP_PKEY_RSA) {
        RSA *x = pStoredPublicKey->pkey.rsa;
        bn = x->n;
}
else if(pStoredPublicKey->type == EVP_PKEY_DSA) {

}
else if(pStoredPublicKey->type == EVP_PKEY_EC) {
}
else {
        printf(" : Unkown publicKey\n");
}
//extracts the bytes from public key & convert into unsigned char buffer
buf_len = (size_t) BN_num_bytes (bn);
key = (unsigned char *)malloc (buf_len);
n = BN_bn2bin (bn, (unsigned char *) key);
for (i = 0; i < n; i++)
{
        printf("%02x\n", (unsigned char) key[i]);
}
keyLen = EVP_PKEY_size(pStoredPublicKey);
EVP_PKEY_free(pStoredPublicKey);

并且，使用此未签名的char缓冲区，如何获取RSA的EVP_PKEY? OR 我可以使用以下???，

And, With this unsigned char buffer, How do I get back the EVP_PKEY for RSA? OR Can I use following ???,

EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **a, unsigned char **pp, long length);
int i2d_PublicKey(EVP_PKEY *a, unsigned char **pp);

推荐答案

以下openssl API适用于EVP_PKEY的未签名char缓冲区，

The following openssl API works for unsigned char buffer to EVP_PKEY,

EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **a, unsigned char **pp, long length);
int i2d_PublicKey(EVP_PKEY *a, unsigned char **pp);

而且，以下用于将EVP_PKEY转换为未签名的char缓冲区.

And, the following works for Convert EVP_PKEY to unsigned char buffer.

int pkeyLen;
unsigned char *ucBuf, *uctempBuf;
pkeyLen = i2d_PublicKey(pkey, NULL);
ucBuf = (unsigned char *)malloc(pkeyLen+1);
uctempBuf = ucBuf;
i2d_PublicKey(pkey, &uctempBuf);
int ii;
for (ii = 0; ii < pkeyLen; ii++)
{
        printf("%02x\n", (unsigned char) ucBuf[ii]);
}

谢谢opensid

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