It is known that RSA is a cryptosystem which is used for the security of data transmission. This tutorial introduces how to use RSA to generate a pair of public and private keys on Windows.
Download and install OpenSSL https://www.openssl.org/community/binaries.html.
Find libeay32.lib, ssleay32.lib and libeay32.dll.
The following sample code will generate a public key “public.pem” and a private key “private.pem”.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | #include <stdio.h>#include <openssl/rsa.h>#include <openssl/pem.h>bool generate_key(){ int ret = 0; RSA *r = NULL; BIGNUM *bne = NULL; BIO *bp_public = NULL, *bp_private = NULL; int bits = 2048; unsigned long e = RSA_F4; // 1. generate rsa key bne = BN_new(); ret = BN_set_word(bne,e); if(ret != 1){ goto free_all; } r = RSA_new(); ret = RSA_generate_key_ex(r, bits, bne, NULL); if(ret != 1){ goto free_all; } // 2. save public key bp_public = BIO_new_file("public.pem", "w+"); ret = PEM_write_bio_RSAPublicKey(bp_public, r); if(ret != 1){ goto free_all; } // 3. save private key bp_private = BIO_new_file("private.pem", "w+"); ret = PEM_write_bio_RSAPrivateKey(bp_private, r, NULL, NULL, 0, NULL, NULL); // 4. freefree_all: BIO_free_all(bp_public); BIO_free_all(bp_private); RSA_free(r); BN_free(bne); return (ret == 1);}int main(int argc, char* argv[]) { generate_key(); return 0;} |
You can feel free to download the sample code, and run it in Visual Studio.
https://www.codepool.biz/how-to-use-openssl-generate-rsa-keys-cc.html