如何在openssl中将纯文本公钥转换为der

Question

如何将以下公钥转换为der编码的公钥？ 谢谢，我可能看到了 i2d_PUBKEY，但我不知道该怎么做。

#include <openssl/evp.h>
#include <openssl/x509.h>

uint8_t *pubkey = NULL;
size_t len = 0;

get_pubkey_function(&pubkey, &len);
printf(pubkey);
/* this step will print out 
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE+GmnZ1UZqKfa81Yh0CG6huQPhYON
Q0W7AE4whuX+oUOg+BewYSOLUwj5zfwRB3i7T07HoltPfAOYeHI57Oe7jA==
-----END PUBLIC KEY-----
*/

Answer 1

    EVP_PKEY *public_key = NULL;
    BIO *bio = NULL;
    bio = BIO_new_mem_buf((void *)pubkey, -1);
    PEM_read_bio_PUBKEY(bio, &public_key, NULL, NULL);
    EXPECT_TRUE(public_key);

我说得对吗？

Answer 2

很晚了，但以防万一有人需要答案：

EVP_PKEY *key = EVP_PKEY_new();
EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, NULL);
EVP_PKEY_keygen_init(ctx); // initialize context
EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, 4096); //making 4096 bits makes it more secure
EVP_PKEY_keygen(ctx, &key); //add context to the key

现在假设

char[64] path = "/path/to/your/file.der"

FILE* key_file = fopen(path, 'w');
if(!i2d_PUBKEY_fp(key_file, key)){    //Writes the key to the file stream.
        fprintf(stderr, "BLOCKCHAIN ERROR! Failed to write public key for account %s\n", username);
        fclose(key_file);
        EVP_PKEY_CTX_free(ctx);
        return -1;
    }
fclose(key_file);
EVP_PKEY_CTX_free(ctx);