[java] 암호화 AES / RSA

[AES 암,복호화]

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package sample;   import java.io.UnsupportedEncodingException; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException;   import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.NoSuchPaddingException; import javax.crypto.spec.SecretKeySpec;   public class AESEncryptionSample {           public static void main(String[] args) throws NoSuchAlgorithmException                 , NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException                 , BadPaddingException, UnsupportedEncodingException {                   // 암호화에 사용할 키, 디폴트로 128bit(16Byte)         String encryptionKey = "happyprogrammer!";                   // 암호화할 문자열         String target = "Java 마스터!";                          // AES로 암호화 =================================================                    // AES Cipher 객체 생성         Cipher cipher = Cipher.getInstance("AES");                   // 암호화 Chipher 초기화         SecretKeySpec secretKeySpec = new SecretKeySpec(encryptionKey.getBytes(),"AES");         cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);                   // 암호화 완료         byte[] encryptBytes = cipher.doFinal(target.getBytes("UTF-8"));         System.out.println(new String(encryptBytes)); // => 똑같은 암호화키로 복호화                             // AES로 복호화 =================================================                   // 복호화 Chipher 초기화, 똑같은 암호화키로 복호화         cipher.init(cipher.DECRYPT_MODE, secretKeySpec);         byte[] decryptBytes = cipher.doFinal(encryptBytes);         System.out.println(new String(decryptBytes, "UTF-8"));     }       }

 

[RSA 암,복호화]

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package sample;   import java.io.UnsupportedEncodingException; import java.security.InvalidKeyException; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey;   import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.NoSuchPaddingException;       public class RSAEncryptionSample {       public static void main(String[] args) throws NoSuchAlgorithmException             , NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException             , BadPaddingException, UnsupportedEncodingException {                   // 암호화할 문자열         String target = "Java 마스터!";                          // RSA 로 암호화 =================================================                   // RSA 비밀키와 공개키를 생성         KeyPairGenerator keypairgen = KeyPairGenerator.getInstance("RSA");         KeyPair keyPair = keypairgen.generateKeyPair();         RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();         RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();                    // Cipher 객체 생성과 비밀키 초기화         Cipher cipher = Cipher.getInstance("RSA");         cipher.init(Cipher.ENCRYPT_MODE, privateKey);                   // 암호화 완료         byte[] encryptBytes = cipher.doFinal(target.getBytes());         System.out.println(new String(encryptBytes)); // => 암호화되어 읽지못함                   // RSA로 복호화 =================================================                   // 복호화 Chipher 초기화, 비밀키와 쌍인 공개키로 복호화함.         cipher.init(cipher.DECRYPT_MODE, publicKey);         byte[] decryptBytes = cipher.doFinal(encryptBytes);         System.out.println(new String(decryptBytes));     }   }

 

[출처]

https://blog.naver.com/PostView.nhn?blogId=javaking75&logNo=220552245734&categoryNo=64&parentCategoryNo=0&viewDate=&currentPage=1&postListTopCurrentPage=1&from=search 

[Java] 암호화를 위한 Cipher 클래스 (Java로 AES, RSA 암호화, 복호화)