1 files changed, 65 insertions, 0 deletions
diff --git a/store/works/life/information-security-experiment/rsa.cpp b/store/works/life/information-security-experiment/rsa.cpp
new file mode 100644
index 0000000..5b88284
--- /dev/null
+++ b/store/works/life/information-security-experiment/rsa.cpp
@@ -0,0 +1,65 @@
+#include <openssl/evp.h>
+#include <openssl/rsa.h>
+
+#include <iomanip>
+#include <iostream>
+#include <vector>
+
+int main() {
+
+  auto ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, nullptr);
+  EVP_PKEY *pkey = NULL;
+  EVP_PKEY_keygen_init(ctx);
+  EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, 2048);
+  EVP_PKEY_keygen(ctx, &pkey);
+  EVP_PKEY_CTX_free(ctx);
+  ctx = nullptr;
+
+  unsigned char cleartext[] = "abc";
+  int cleartext_size = sizeof(cleartext) / sizeof(cleartext[0]);
+
+  EVP_MD_CTX *md_ctx = EVP_MD_CTX_create();
+  EVP_DigestInit_ex(md_ctx, EVP_sha256(), NULL);
+  EVP_DigestUpdate(md_ctx, cleartext, cleartext_size);
+  unsigned char digest[EVP_MAX_MD_SIZE];
+  unsigned int digest_size;
+  EVP_DigestFinal_ex(md_ctx, digest, &digest_size);
+  EVP_MD_CTX_destroy(md_ctx);
+  md_ctx = nullptr;
+  std::cout << "SHA256 digest of 'abc' is: " << std::hex << std::setfill('0');
+  for (unsigned int i = 0; i < digest_size; i++) {
+    std::cout << std::setw(2) << (int)digest[i];
+  }
+  std::cout << std::endl;
+
+  std::vector<unsigned char> sig;
+  size_t sig_len;
+
+  ctx = EVP_PKEY_CTX_new(pkey, nullptr);
+  EVP_PKEY_sign_init(ctx);
+  EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING);
+  EVP_PKEY_sign(ctx, nullptr, &sig_len, digest, digest_size);
+  sig.resize(sig_len);
+  EVP_PKEY_sign(ctx, sig.data(), &sig_len, digest, digest_size);
+  EVP_PKEY_CTX_free(ctx);
+
+  std::cout << "Signature: " << std::hex << std::setfill('0');
+  for (auto c : sig) {
+    std::cout << std::setw(2) << static_cast<int>(c);
+  }
+  std::cout << std::endl;
+
+  ctx = EVP_PKEY_CTX_new(pkey, nullptr);
+  EVP_PKEY_verify_init(ctx);
+  EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING);
+  auto result = EVP_PKEY_verify(ctx, sig.data(), sig_len, digest, digest_size);
+  if (result == 1) {
+    std::cout << "Verification succeeded." << std::endl;
+  } else if (result == 0) {
+    std::cout << "Verification failed." << std::endl;
+  } else {
+    std::cerr << "Verification error." << std::endl;
+  }
+
+  return 0;
+}
+\ No newline at end of file