From a1901f53c12ef44bd05742fdb407dccc826c5143 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Ko=C5=BEusznik?= <jan@kozusznik.cz>
Date: Mon, 3 May 2021 15:53:20 +0200
Subject: [PATCH] solution
---
.../java/java2/koz01/lab13/KeyPairLoader.java | 33 +++++++++
.../java/java2/koz01/lab13/Lab13Decrypt.java | 59 ++++++++++++++++
.../java/java2/koz01/lab13/Lab13Encrypt.java | 68 +++++++++++++++++++
.../java2/koz01/lab13/Lab13GenerateKeys.java | 44 ++++++++++++
4 files changed, 204 insertions(+)
create mode 100644 src/main/java/java2/koz01/lab13/KeyPairLoader.java
create mode 100644 src/main/java/java2/koz01/lab13/Lab13Decrypt.java
create mode 100644 src/main/java/java2/koz01/lab13/Lab13Encrypt.java
create mode 100644 src/main/java/java2/koz01/lab13/Lab13GenerateKeys.java
diff --git a/src/main/java/java2/koz01/lab13/KeyPairLoader.java b/src/main/java/java2/koz01/lab13/KeyPairLoader.java
new file mode 100644
index 0000000..2846724
--- /dev/null
+++ b/src/main/java/java2/koz01/lab13/KeyPairLoader.java
@@ -0,0 +1,33 @@
+package java2.koz01.lab13;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.math.BigInteger;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.RSAPrivateKeySpec;
+import java.security.spec.RSAPublicKeySpec;
+
+public class KeyPairLoader {
+
+ private KeyFactory kf;
+
+ public KeyPairLoader() throws NoSuchAlgorithmException {
+ kf = KeyFactory.getInstance("RSA");
+ }
+
+ public KeyPair load(String file) throws IOException, InvalidKeySpecException {
+ try (BufferedReader br = Files.newBufferedReader(Paths.get(file))) {
+ BigInteger modulus = new BigInteger(br.readLine());
+ BigInteger pubExp = new BigInteger(br.readLine());
+ BigInteger privExp = new BigInteger(br.readLine());
+ RSAPrivateKeySpec priv = new RSAPrivateKeySpec(modulus, privExp);
+ RSAPublicKeySpec pub = new RSAPublicKeySpec(modulus, pubExp);
+ return new KeyPair(kf.generatePublic(pub), kf.generatePrivate(priv));
+ }
+ }
+}
diff --git a/src/main/java/java2/koz01/lab13/Lab13Decrypt.java b/src/main/java/java2/koz01/lab13/Lab13Decrypt.java
new file mode 100644
index 0000000..1af91c7
--- /dev/null
+++ b/src/main/java/java2/koz01/lab13/Lab13Decrypt.java
@@ -0,0 +1,59 @@
+package java2.koz01.lab13;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.security.InvalidKeyException;
+import java.security.KeyPair;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.CipherInputStream;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.spec.SecretKeySpec;
+
+import lombok.extern.log4j.Log4j2;
+
+@Log4j2
+public class Lab13Decrypt {
+
+ public static void main(String[] args) throws InvalidKeyException,
+ NoSuchAlgorithmException, NoSuchPaddingException, IOException,
+ InvalidKeySpecException, IllegalBlockSizeException, BadPaddingException
+ {
+
+ KeyPairLoader keyPairLoader = new KeyPairLoader();
+ KeyPair kp = keyPairLoader.load("keys.rsa");
+
+
+
+ InputStream nis = new FileInputStream(args[0]);
+ Cipher aCipher = Cipher.getInstance("RSA");
+ aCipher.init(Cipher.DECRYPT_MODE, kp.getPrivate());
+ byte[] encrypted = new byte[256];
+ nis.read(encrypted);
+ byte[] keyData = aCipher.doFinal(encrypted);
+ SecretKeySpec skp = new SecretKeySpec(keyData, "AES");
+
+ Cipher cipher = Cipher.getInstance("AES");
+ cipher.init(Cipher.DECRYPT_MODE, skp);
+
+
+ try (InputStream is = new CipherInputStream(nis,
+ cipher);
+ OutputStream os = new FileOutputStream(args[1]))
+ {
+ byte [] buffer = new byte[1024];
+ int len;
+ while (-1 != (len = is.read(buffer))) {
+ os.write(buffer, 0, len);
+ }
+ }
+ log.info("decrypted");
+ }
+}
diff --git a/src/main/java/java2/koz01/lab13/Lab13Encrypt.java b/src/main/java/java2/koz01/lab13/Lab13Encrypt.java
new file mode 100644
index 0000000..6acb767
--- /dev/null
+++ b/src/main/java/java2/koz01/lab13/Lab13Encrypt.java
@@ -0,0 +1,68 @@
+package java2.koz01.lab13;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.security.InvalidKeyException;
+import java.security.KeyPair;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.CipherOutputStream;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.KeyGenerator;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+
+import lombok.extern.log4j.Log4j2;
+
+@Log4j2
+public class Lab13Encrypt {
+
+ public static void main(String[] args) throws NoSuchAlgorithmException,
+ IOException, NoSuchPaddingException, InvalidKeyException,
+ InvalidKeySpecException, IllegalBlockSizeException, BadPaddingException
+ {
+
+ KeyPairLoader keyPairLoader = new KeyPairLoader();
+ KeyPair kp = keyPairLoader.load("keys.rsa");
+ KeyGenerator kg = KeyGenerator.getInstance("AES");
+ kg.init(256);
+ SecretKey sk = kg.generateKey();
+
+
+ /*try (OutputStream os = Files.newOutputStream(Paths.get("secretkey.aes"))) {
+ os.write(sk.getEncoded());
+ }*/
+
+
+ Cipher cipher = Cipher.getInstance("AES");
+ cipher.init(Cipher.ENCRYPT_MODE, sk);
+ // 1. argument - input
+ // 2. argument - output
+ byte[] buffer = new byte[1024];
+ OutputStream nos;
+ try (InputStream is = new FileInputStream(args[0]);
+ OutputStream os = new CipherOutputStream(nos = new FileOutputStream(
+ args[1]),
+ cipher))
+ {
+ Cipher aCipher = Cipher.getInstance("RSA");
+ aCipher.init(Cipher.ENCRYPT_MODE, kp.getPublic());
+ log.info("size of key {}", sk.getEncoded().length);
+ byte[] encrypted = aCipher.doFinal(sk.getEncoded());
+ log.info("size of encrypted {}", encrypted.length);
+ nos.write(encrypted);
+ nos.flush();
+ int len;
+ while (-1 != (len = is.read(buffer))) {
+ os.write(buffer, 0, len);
+ }
+ }
+ log.info("encryption done!");
+ }
+}
diff --git a/src/main/java/java2/koz01/lab13/Lab13GenerateKeys.java b/src/main/java/java2/koz01/lab13/Lab13GenerateKeys.java
new file mode 100644
index 0000000..40f1722
--- /dev/null
+++ b/src/main/java/java2/koz01/lab13/Lab13GenerateKeys.java
@@ -0,0 +1,44 @@
+package java2.koz01.lab13;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.RSAPrivateKeySpec;
+import java.security.spec.RSAPublicKeySpec;
+
+import lombok.extern.log4j.Log4j2;
+
+@Log4j2
+public class Lab13GenerateKeys {
+
+ public static void main(String[] args) throws NoSuchAlgorithmException,
+ IOException, InvalidKeySpecException
+ {
+
+ KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
+ kpg.initialize(2048);
+ KeyPair kp = kpg.generateKeyPair();
+
+ log.info("private: {}", kp.getPrivate());
+ log.info("public: {}", kp.getPublic());
+ KeyFactory kf = KeyFactory.getInstance("RSA");
+ RSAPrivateKeySpec pri = kf.getKeySpec(kp.getPrivate(),
+ RSAPrivateKeySpec.class);
+ RSAPublicKeySpec pub = kf.getKeySpec(kp.getPublic(),
+ RSAPublicKeySpec.class);
+
+ try (BufferedWriter bw = Files.newBufferedWriter(Paths.get("keys.rsa"))) {
+ bw.write(pub.getModulus().toString());
+ bw.newLine();
+ bw.write(pub.getPublicExponent().toString());
+ bw.newLine();
+ bw.write(pri.getPrivateExponent().toString());
+ }
+ }
+}
--
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