+ public static void main(String[] args) {
+ final String ALGORITHM = "RSA";
+ final String provider = "BC";
+ SecureRandom secureRandom = new SecureRandom();
+ long begin = System.currentTimeMillis();
+ for (int i = 512; i < 1024; i = i + 2) {
+ try {
+ KeyPairGenerator keyGen = KeyPairGenerator.getInstance(ALGORITHM,provider);
+ keyGen.initialize(i, secureRandom);
+ keyGen.generateKeyPair();
+ } catch (Exception e) {
+ System.err.println(i + " : " + e.getMessage());
+ }
+ }
+ System.out.println( (System.currentTimeMillis() - begin) + " ms");
+
+// // String text = "a";
+// String text = "testtesttesttesttesttesttesttesttesttesttesttesttesttesttest";
+// try {
+// System.out.println(text);
+// PrivateKey privateKey;
+// PublicKey publicKey;
+// char[] password = "changeit".toCharArray();
+// String alias = "CN=test";
+// KeyStore keyStore = KeyStore.getInstance("pkcs12");
+// File p12file = new File("test.p12");
+// p12file.delete();
+// if (!p12file.exists()) {
+// keyStore.load(null);
+// generateSelfSignedCertificate(keyStore, new X500Principal(alias), 513, password);
+// try (OutputStream out = new FileOutputStream(p12file)) {
+// keyStore.store(out, password);
+// }
+// }
+// try (InputStream in = new FileInputStream(p12file)) {
+// keyStore.load(in, password);
+// privateKey = (PrivateKey) keyStore.getKey(alias, password);
+// publicKey = keyStore.getCertificateChain(alias)[0].getPublicKey();
+// }
+// // KeyPair key;
+// // final KeyPairGenerator keyGen =
+// // KeyPairGenerator.getInstance(ALGORITHM);
+// // keyGen.initialize(4096, new SecureRandom());
+// // long begin = System.currentTimeMillis();
+// // key = keyGen.generateKeyPair();
+// // System.out.println((System.currentTimeMillis() - begin) + " ms");
+// // keyStore.load(null);
+// // keyStore.setKeyEntry("test", key.getPrivate(), password, null);
+// // try(OutputStream out=new FileOutputStream(p12file)) {
+// // keyStore.store(out, password);
+// // }
+// // privateKey = key.getPrivate();
+// // publicKey = key.getPublic();
+//
+// Cipher encrypt = Cipher.getInstance(ALGORITHM);
+// encrypt.init(Cipher.ENCRYPT_MODE, publicKey);
+// byte[] encrypted = encrypt.doFinal(text.getBytes());
+// String encryptedBase64 = Base64.getEncoder().encodeToString(encrypted);
+// System.out.println(encryptedBase64);
+// byte[] encryptedFromBase64 = Base64.getDecoder().decode(encryptedBase64);
+//
+// Cipher decrypt = Cipher.getInstance(ALGORITHM);
+// decrypt.init(Cipher.DECRYPT_MODE, privateKey);
+// byte[] decrypted = decrypt.doFinal(encryptedFromBase64);
+// System.out.println(new String(decrypted));
+// } catch (Exception e) {
+// e.printStackTrace();
+// }
+
+ }
+