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mkyongmkyong
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add java-crypto
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8 files changed

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‎java-crypto/pom.xml‎

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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
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http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>com.mkyong</groupId>
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<artifactId>crypto</artifactId>
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<version>1.0</version>
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<name>java-crypto</name>
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<url>https://mkyong.com</url>
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<properties>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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<maven.compiler.source>11</maven.compiler.source>
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<maven.compiler.target>11</maven.compiler.target>
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<java.version>11</java.version>
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<junit.version>5.4.0</junit.version>
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</properties>
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<dependencies>
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<dependency>
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<groupId>org.junit.jupiter</groupId>
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<artifactId>junit-jupiter-params</artifactId>
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<version>${junit.version}</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>commons-codec</groupId>
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<artifactId>commons-codec</artifactId>
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<version>1.14</version>
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</dependency>
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</dependencies>
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<build>
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<finalName>java11</finalName>
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<plugins>
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<plugin>
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<groupId>org.apache.maven.plugins</groupId>
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<artifactId>maven-compiler-plugin</artifactId>
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<version>3.8.0</version>
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<configuration>
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<source>${java.version}</source>
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<target>${java.version}</target>
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</configuration>
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</plugin>
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</plugins>
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</build>
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</project>

‎java-crypto/src/main/java/com/mkyong/HelloApp.java‎

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package com.mkyong;
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public class HelloApp {
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public static void main(String[] args) {
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System.out.println("Hello Java Crypto!");
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}
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}

‎java-crypto/src/main/java/com/mkyong/crypto/encryptor/EncryptorAesCbc.java‎

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package com.mkyong.crypto.encryptor;
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import com.mkyong.crypto.utils.CryptoUtils;
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import javax.crypto.Cipher;
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import javax.crypto.SecretKey;
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import javax.crypto.spec.IvParameterSpec;
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import java.nio.ByteBuffer;
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import java.nio.charset.Charset;
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import java.nio.charset.StandardCharsets;
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/**
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* AES-CBC inputs - 16 bytes IV, need the same IV and secret keys for encryption and decryption.
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* <p>
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* The output consist of iv, encrypted content and auth tag in the following format:
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* output = byte[] {i i i c c c c c c ...}
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* <p>
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* i = IV bytes
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* c = content bytes (encrypted content)
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*/
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public class EncryptorAesCbc {
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// AES-CBC, IvParameterSpec, 16 bytes IV
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private static final String ENCRYPT_ALGO = "AES/CBC/PKCS5Padding";
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private static final int IV_LENGTH_BYTE = 16;
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private static final int AES_KEY_BIT = 256;
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private static final Charset UTF_8 = StandardCharsets.UTF_8;
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// AES-CBC needs IvParameterSpec
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public static byte[] encrypt(byte[] pText, SecretKey secret, byte[] iv) throws Exception {
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Cipher cipher = Cipher.getInstance(ENCRYPT_ALGO);
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cipher.init(Cipher.ENCRYPT_MODE, secret, new IvParameterSpec(iv));
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byte[] encryptedText = cipher.doFinal(pText);
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return encryptedText;
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}
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// prefix IV length + IV bytes to cipher text
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public static byte[] encryptWithPrefixIV(byte[] pText, SecretKey secret, byte[] iv) throws Exception {
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byte[] cipherText = encrypt(pText, secret, iv);
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byte[] cipherTextWithIv = ByteBuffer.allocate(iv.length + cipherText.length)
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.put(iv)
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.put(cipherText)
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.array();
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return cipherTextWithIv;
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}
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public static String decrypt(byte[] cText, SecretKey secret, byte[] iv) throws Exception {
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Cipher cipher = Cipher.getInstance(ENCRYPT_ALGO);
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cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
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byte[] plainText = cipher.doFinal(cText);
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return new String(plainText, UTF_8);
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}
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public static String decryptWithPrefixIV(byte[] cText, SecretKey secret) throws Exception {
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ByteBuffer bb = ByteBuffer.wrap(cText);
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byte[] iv = new byte[IV_LENGTH_BYTE];
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bb.get(iv);
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//bb.get(iv, 0, iv.length);
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byte[] cipherText = new byte[bb.remaining()];
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bb.get(cipherText);
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String plainText = decrypt(cipherText, secret, iv);
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return plainText;
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}
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public static void main(String[] args) throws Exception {
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String OUTPUT_FORMAT = "%-30s:%s";
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String pText = "Hello World AES-CBC";
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// encrypt and decrypt need the same key.
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// get AES 256 bits (32 bytes) key
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SecretKey secretKey = CryptoUtils.getAESKey(AES_KEY_BIT);
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// encrypt and decrypt need the same IV.
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// AES-CBC needs IV 128-bit (16 bytes)
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byte[] iv = CryptoUtils.getRandomNonce(IV_LENGTH_BYTE);
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byte[] encryptedText = EncryptorAesCbc.encryptWithPrefixIV(pText.getBytes(UTF_8), secretKey, iv);
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System.out.println("\n------ AES CBC Encryption ------");
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System.out.println(String.format(OUTPUT_FORMAT, "Input (plain text)", pText));
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System.out.println(String.format(OUTPUT_FORMAT, "Key (hex)", CryptoUtils.hex(secretKey.getEncoded())));
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System.out.println(String.format(OUTPUT_FORMAT, "IV (hex)", CryptoUtils.hex(iv)));
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System.out.println(String.format(OUTPUT_FORMAT, "Encrypted (hex) ", CryptoUtils.hex(encryptedText)));
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System.out.println(String.format(OUTPUT_FORMAT, "Encrypted (hex) (block = 16)", CryptoUtils.hexWithBlockSize(encryptedText, 16)));
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System.out.println("\n------ AES CBC Decryption ------");
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System.out.println(String.format(OUTPUT_FORMAT, "Input (hex)", CryptoUtils.hex(encryptedText)));
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System.out.println(String.format(OUTPUT_FORMAT, "Input (hex) (block = 16)", CryptoUtils.hexWithBlockSize(encryptedText, 16)));
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System.out.println(String.format(OUTPUT_FORMAT, "Key (hex)", CryptoUtils.hex(secretKey.getEncoded())));
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String decryptedText = EncryptorAesCbc.decryptWithPrefixIV(encryptedText, secretKey);
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System.out.println(String.format(OUTPUT_FORMAT, "Decrypted (plain text)", decryptedText));
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}
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}

‎java-crypto/src/main/java/com/mkyong/crypto/encryptor/EncryptorAesGcm.java‎

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package com.mkyong.crypto.encryptor;
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import com.mkyong.crypto.utils.CryptoUtils;
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import javax.crypto.Cipher;
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import javax.crypto.SecretKey;
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import javax.crypto.spec.GCMParameterSpec;
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import java.nio.ByteBuffer;
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import java.nio.charset.Charset;
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import java.nio.charset.StandardCharsets;
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/**
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* AES-GCM inputs - 12 bytes IV, need the same IV and secret keys for encryption and decryption.
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* <p>
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* The output consist of iv, encrypted content and auth tag in the following format:
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* output = byte[] {i i i c c c c c c ...}
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* <p>
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* i = IV bytes
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* c = content bytes (encrypted content, auth tag)
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*/
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public class EncryptorAesGcm {
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// AES-CBC
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// IvParameterSpec, 16 bytes IV
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// private static final String ENCRYPT_ALGO = "AES/CBC/PKCS5Padding";
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private static final String ENCRYPT_ALGO = "AES/GCM/NoPadding";
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private static final int TAG_LENGTH_BIT = 128;
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private static final int IV_LENGTH_BYTE = 12;
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private static final int AES_KEY_BIT = 256;
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private static final Charset UTF_8 = StandardCharsets.UTF_8;
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// AES-GCM needs GCMParameterSpec
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public static byte[] encrypt(byte[] pText, SecretKey secret, byte[] iv) throws Exception {
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Cipher cipher = Cipher.getInstance(ENCRYPT_ALGO);
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cipher.init(Cipher.ENCRYPT_MODE, secret, new GCMParameterSpec(TAG_LENGTH_BIT, iv));
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byte[] encryptedText = cipher.doFinal(pText);
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return encryptedText;
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}
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// prefix IV length + IV bytes to cipher text
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public static byte[] encryptWithPrefixIV(byte[] pText, SecretKey secret, byte[] iv) throws Exception {
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byte[] cipherText = encrypt(pText, secret, iv);
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byte[] cipherTextWithIv = ByteBuffer.allocate(iv.length + cipherText.length)
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.put(iv)
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.put(cipherText)
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.array();
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return cipherTextWithIv;
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}
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public static String decrypt(byte[] cText, SecretKey secret, byte[] iv) throws Exception {
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Cipher cipher = Cipher.getInstance(ENCRYPT_ALGO);
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cipher.init(Cipher.DECRYPT_MODE, secret, new GCMParameterSpec(TAG_LENGTH_BIT, iv));
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byte[] plainText = cipher.doFinal(cText);
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return new String(plainText, UTF_8);
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}
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public static String decryptWithPrefixIV(byte[] cText, SecretKey secret) throws Exception {
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ByteBuffer bb = ByteBuffer.wrap(cText);
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byte[] iv = new byte[IV_LENGTH_BYTE];
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bb.get(iv);
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//bb.get(iv, 0, iv.length);
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byte[] cipherText = new byte[bb.remaining()];
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bb.get(cipherText);
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String plainText = decrypt(cipherText, secret, iv);
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return plainText;
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}
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public static void main(String[] args) throws Exception {
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String OUTPUT_FORMAT = "%-30s:%s";
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String pText = "Hello World AES-GCM, Welcome to Cryptography!";
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// encrypt and decrypt need the same key.
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// get AES 256 bits (32 bytes) key
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SecretKey secretKey = CryptoUtils.getAESKey(AES_KEY_BIT);
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// encrypt and decrypt need the same IV.
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// AES-GCM needs IV 96-bit (12 bytes)
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byte[] iv = CryptoUtils.getRandomNonce(IV_LENGTH_BYTE);
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byte[] encryptedText = EncryptorAesGcm.encryptWithPrefixIV(pText.getBytes(UTF_8), secretKey, iv);
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System.out.println("\n------ AES GCM Encryption ------");
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System.out.println(String.format(OUTPUT_FORMAT, "Input (plain text)", pText));
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System.out.println(String.format(OUTPUT_FORMAT, "Key (hex)", CryptoUtils.hex(secretKey.getEncoded())));
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System.out.println(String.format(OUTPUT_FORMAT, "IV (hex)", CryptoUtils.hex(iv)));
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System.out.println(String.format(OUTPUT_FORMAT, "Encrypted (hex) ", CryptoUtils.hex(encryptedText)));
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System.out.println(String.format(OUTPUT_FORMAT, "Encrypted (hex) (block = 16)", CryptoUtils.hexWithBlockSize(encryptedText, 16)));
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System.out.println("\n------ AES GCM Decryption ------");
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System.out.println(String.format(OUTPUT_FORMAT, "Input (hex)", CryptoUtils.hex(encryptedText)));
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System.out.println(String.format(OUTPUT_FORMAT, "Input (hex) (block = 16)", CryptoUtils.hexWithBlockSize(encryptedText, 16)));
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System.out.println(String.format(OUTPUT_FORMAT, "Key (hex)", CryptoUtils.hex(secretKey.getEncoded())));
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String decryptedText = EncryptorAesGcm.decryptWithPrefixIV(encryptedText, secretKey);
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System.out.println(String.format(OUTPUT_FORMAT, "Decrypted (plain text)", decryptedText));
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}
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}

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