情報暗号化の非対称暗号化DHアルゴリズム

非対称暗号化アルゴリズムは対称暗号化アルゴリズムに対して、対称暗号化アルゴリズムについて前のまとめを参照してください.今日はDHアルゴリズムを紹介します.DHは鍵交換アルゴリズムで、受信者は送信者が暗号化したときの鍵に基づいて、受信者の秘密鍵を生成します.一緒に勉強しましょう.
送信者キーの初期化:

KeyPairGenerator sendKeyPairGenerator = KeyPairGenerator.getInstance("DH");
            sendKeyPairGenerator.initialize(512);
            KeyPair sendKeyPair = sendKeyPairGenerator.generateKeyPair();
            byte[] sendPublicKeyEnc = sendKeyPair.getPublic().getEncoded();//       ，      （  、  ...）

受信者キーの初期化:

KeyFactory receiverKeyFactory = KeyFactory.getInstance("DH");
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(sendPublicKeyEnc);
            PublicKey receivePublicKey = receiverKeyFactory.generatePublic(x509EncodedKeySpec);
            DHParameterSpec dhParameterSpec = ((DHPublicKey)receivePublicKey).getParams();
            KeyPairGenerator receiverKeyPairGenerator = KeyPairGenerator.getInstance("DH");
            receiverKeyPairGenerator.initialize(dhParameterSpec);
            KeyPair receiverKeyPair = receiverKeyPairGenerator.generateKeyPair();
            PrivateKey receiverPrivateKey = receiverKeyPair.getPrivate();
            byte[] receiverPublicKeyEnc = receiverKeyPair.getPublic().getEncoded();

受信者キーの構築:

KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH");
            receiverKeyAgreement.init(receiverPrivateKey);
            receiverKeyAgreement.doPhase(receivePublicKey, true);
            
            SecretKey receiverDESKey = receiverKeyAgreement.generateSecret("DES");//   Key

送信者キーの構築:

KeyFactory sendKeyFactory = KeyFactory.getInstance("DH");
            x509EncodedKeySpec = new X509EncodedKeySpec(receiverPublicKeyEnc);
            PublicKey sendPublicKey = sendKeyFactory.generatePublic(x509EncodedKeySpec);
            
            KeyAgreement sendKeyAgreement = KeyAgreement.getInstance("DH");
            sendKeyAgreement.init(sendKeyPair.getPrivate());
            sendKeyAgreement.doPhase(sendPublicKey, true);
            
            SecretKey sendDESKey = sendKeyAgreement.generateSecret("DES");//   Key

送信者の暗号化:

Cipher sendCipher = Cipher.getInstance("DES");
            sendCipher.init(Cipher.ENCRYPT_MODE, sendDESKey);
            byte[] sendResult = sendCipher.doFinal(src.getBytes());
            System.out.println("sendResult ："+Hex.encodeHexString(sendResult));

受信者の復号化:

Cipher receiverCipher = Cipher.getInstance("DES");
            receiverCipher.init(Cipher.DECRYPT_MODE, receiverDESKey);
            byte[] receiverResult = receiverCipher.doFinal(sendResult);
            System.out.println("receiverResult : "+new String (receiverResult));

鍵交換に基づく非対称暗号化アルゴリズム(DH)については,ここまでにまとめる.