refactors example code (variable names) and base64 usage

kmindi · kmindi · commit 0aa41a87b55b · 2018-05-13T09:29:56.000+02:00
diff --git a/java_landing_page.md b/java_landing_page.md
@@ -9,11 +9,11 @@ is_landingpage: 1
 
 # Available Crypto Scenarios and Use Cases
 
-|                                                 | All in One                             | Easy Object oriented                 |
-|-------------------------------------------------|----------------------------------------|--------------------------------------|
-| Symmetric Encryption                            | [String Encryption (password based) ✔](java_string_encryption_password_based_symmetric.html) <br />[String Encryption (key based) ✔](java_string_encryption_key_based_symmetric.html) <br />[File Encryption ✔](java_file_encryption_symmetric_password_based.html) | [String Encryption with separate class ✔](java_easy_AES_string_encryption.html) <br />[File Encryption with separate class ✔](java_easy_AES_file_encryption.html) |
-| Asymmetric Encryption / Public Key Cryptography | [String Encryption ✔](java_asymmetric_string_encryption.html) |                                      |
-| Key Storage                                     |                                        |                                      |
-| Hashing                                         | [String Hash ✔](java_string_hash.html)      | N/A                                  |
-| Crypto Provider Setup                           |                                        |                                      |
-| Digital Signatures                              | [String Signing ✔](java_string_sign.html)                                       |                                      |
+|                                                 | All in One                             |
+|-------------------------------------------------|----------------------------------------|
+| Symmetric Encryption                            | [Symmetric String Encryption (password based) ✔](java_string_encryption_password_based_symmetric.html) <br />[Symmetric String Encryption (key based) ✔](java_string_encryption_key_based_symmetric.html) <br />[Symmetric File Encryption ✔](java_file_encryption_symmetric_password_based.html) |
+| Asymmetric Encryption / Public Key Cryptography | [Asymmetric String Encryption ✔](java_asymmetric_string_encryption.html) |                                      |
+| Key Storage                                     |                                        |
+| Hashing                                         | [String Hash ✔](java_string_hash.html)      |
+| Crypto Provider Setup                           |                                        |
+| Digital Signatures                              | [String Signing ✔](java_string_sign.html) |
diff --git a/java_string_encryption_asymmetric.md b/java_string_encryption_asymmetric.md
@@ -24,7 +24,7 @@ current_reviews: [
 
 ]
 # Indicates when this example was last updated/created. Reviews don't change this.
-last_updated: "2018-04-28"
+last_updated: "2018-05-13"
 tags: [Java, RSA, Asymmetric, String, Encryption]
 ---
 
diff --git a/java_string_encryption_key_based_symmetric.md b/java_string_encryption_key_based_symmetric.md
@@ -4,6 +4,27 @@ keywords: sample
 summary: "String encryption in Java with key generation"
 permalink: java_string_encryption_key_based_symmetric.html
 folder: Java JDK
+references: [
+    # Place a list of references used to create and/or understand this example.
+    {
+        url: "https://docs.oracle.com/javase/10/docs/api/javax/crypto/Cipher.html",
+        description: "Oracle JDK Cipher Documentation"
+    }
+]
+authors: [
+    {
+        name: "Kai Mindermann",
+        url: "https://github.com/kmindi"
+    }
+]
+# List all reviewers that reviewed this version of the example. When the example is updated all old reviews
+# must be removed from the list below and the code has to be reviewed again. The complete review process
+# is documented in the main repository of CryptoExamples
+current_reviews: [
+
+]
+# Indicates when this example was last updated/created. Reviews don't change this.
+last_updated: "2018-05-13"
 tags: [Java, AES, GCM, Salt, AEAD]
 ---
 
diff --git a/java_string_encryption_password_based_symmetric.md b/java_string_encryption_password_based_symmetric.md
@@ -4,6 +4,27 @@ keywords: sample
 summary: "Password based string encryption in Java"
 permalink: java_string_encryption_password_based_symmetric.html
 folder: Java JDK
+references: [
+    # Place a list of references used to create and/or understand this example.
+    {
+        url: "https://docs.oracle.com/javase/10/docs/api/javax/crypto/Cipher.html",
+        description: "Oracle JDK Cipher Documentation"
+    }
+]
+authors: [
+    {
+        name: "Kai Mindermann",
+        url: "https://github.com/kmindi"
+    }
+]
+# List all reviewers that reviewed this version of the example. When the example is updated all old reviews
+# must be removed from the list below and the code has to be reviewed again. The complete review process
+# is documented in the main repository of CryptoExamples
+current_reviews: [
+
+]
+# Indicates when this example was last updated/created. Reviews don't change this.
+last_updated: "2018-05-13"
 tags: [Java, AES, GCM, PBKDF2, Salt, AEAD]
 ---
 
diff --git a/java_string_hash.md b/java_string_hash.md
@@ -4,6 +4,27 @@ keywords: sample
 summary: "Java based string hashing"
 permalink: java_string_hash.html
 folder: Java JDK
+references: [
+    # Place a list of references used to create and/or understand this example.
+    {
+        url: "https://docs.oracle.com/javase/10/docs/api/java/security/MessageDigest.html",
+        description: "Oracle JDK MessageDigest Documentation"
+    }
+]
+authors: [
+    {
+        name: "Kai Mindermann",
+        url: "https://github.com/kmindi"
+    }
+]
+# List all reviewers that reviewed this version of the example. When the example is updated all old reviews
+# must be removed from the list below and the code has to be reviewed again. The complete review process
+# is documented in the main repository of CryptoExamples
+current_reviews: [
+
+]
+# Indicates when this example was last updated/created. Reviews don't change this.
+last_updated: "2018-05-13"
 tags: [Java, hash, SHA, SHA-512]
 ---
 
diff --git a/java_string_sign.md b/java_string_sign.md
@@ -4,6 +4,27 @@ keywords: sample
 summary: "Java based string signing"
 permalink: java_string_sign.html
 folder: Java JDK
+references: [
+    # Place a list of references used to create and/or understand this example.
+    {
+        url: "https://docs.oracle.com/javase/10/docs/api/java/security/Signature.html",
+        description: "Oracle JDK Signature Documentation"
+    }
+]
+authors: [
+    {
+        name: "Kai Mindermann",
+        url: "https://github.com/kmindi"
+    }
+]
+# List all reviewers that reviewed this version of the example. When the example is updated all old reviews
+# must be removed from the list below and the code has to be reviewed again. The complete review process
+# is documented in the main repository of CryptoExamples
+current_reviews: [
+
+]
+# Indicates when this example was last updated/created. Reviews don't change this.
+last_updated: "2018-05-13"
 tags: [Java, hash, SHA, SHA-512]
 ---
 
diff --git a/src/main/java/com/cryptoexamples/java/ExampleAsymmetricStringEncryptionInOneMethod.java b/src/main/java/com/cryptoexamples/java/ExampleAsymmetricStringEncryptionInOneMethod.java
@@ -17,8 +17,8 @@
  * All in one example for asymmetric encryption and decryption of a string in one method.
  * - Generation of public and private RSA 4096 bit keypair
  * - AES-256 authenticated encryption using GCM
- * - BASE64-encoding as representation for the byte-arrays
- * - UTF-8 encoding of String
+ * - BASE64 encoding as representation for the byte-arrays
+ * - UTF-8 encoding of Strings
  * - Exception handling
  */
 public class ExampleAsymmetricStringEncryptionInOneMethod {
@@ -27,7 +27,6 @@ public class ExampleAsymmetricStringEncryptionInOneMethod {
   public static void main(String[] args) {
     String plainText = "Text that is going to be sent over an insecure channel and must be encrypted at all costs!";
     try {
-
       // GENERATE NEW KEYPAIR
       KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
       /* @see https://www.keylength.com/ */
@@ -38,15 +37,15 @@ public static void main(String[] args) {
       Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding");
       cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());
 
-      byte[] byteCipher = cipher.doFinal(plainText.getBytes());
+      byte[] cipherTextBytes = cipher.doFinal(plainText.getBytes());
 
       // CONVERSION of raw bytes to BASE64 representation
-      String cipherText = new String(Base64.getEncoder().encode(byteCipher));
+      String cipherText = Base64.getEncoder().encodeToString(cipherTextBytes);
 
       // DECRYPTION
       cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
-      byte[] decryptedCipher = cipher.doFinal(Base64.getDecoder().decode(cipherText));
-      String decryptedCipherText = new String(decryptedCipher);
+      byte[] decryptedCipherTextBytes = cipher.doFinal(Base64.getDecoder().decode(cipherText));
+      String decryptedCipherText = new String(decryptedCipherTextBytes);
 
       LOGGER.log(Level.INFO, () -> String.format("Decrypted and original plain text are the same: %b", decryptedCipherText.compareTo(plainText) == 0));
     } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | InvalidParameterException  e) {
diff --git a/src/main/java/com/cryptoexamples/java/ExampleFileEncryptionInOneMethod.java b/src/main/java/com/cryptoexamples/java/ExampleFileEncryptionInOneMethod.java
@@ -63,9 +63,9 @@ public static void main(String[] args) {
 
       // SET UP OUTPUT STREAM and write content of String
       try (
-              FileOutputStream fileOutputStream = new FileOutputStream("encryptedFile.enc");
-              CipherOutputStream encryptedOutputStream = new CipherOutputStream(fileOutputStream, cipher);
-              InputStream stringInputStream = new ByteArrayInputStream(plainText.getBytes(StandardCharsets.UTF_8));
+        FileOutputStream fileOutputStream = new FileOutputStream("encryptedFile.enc");
+        CipherOutputStream encryptedOutputStream = new CipherOutputStream(fileOutputStream, cipher);
+        InputStream stringInputStream = new ByteArrayInputStream(plainText.getBytes(StandardCharsets.UTF_8))
       ) {
         byte[] buffer = new byte[8192];
         while (stringInputStream.read(buffer) > 0) {
@@ -79,7 +79,7 @@ public static void main(String[] args) {
       //cipher.updateAAD(aad);
       try (
               FileInputStream fileInputStream = new FileInputStream("encryptedFile.enc");
-              CipherInputStream cipherInputStream = new CipherInputStream(fileInputStream, cipher);
+              CipherInputStream cipherInputStream = new CipherInputStream(fileInputStream, cipher)
       ) {
         byte[] buffer = new byte[8192];
         while (cipherInputStream.read(buffer) > 0) {
diff --git a/src/main/java/com/cryptoexamples/java/ExampleHashInOneMethod.java b/src/main/java/com/cryptoexamples/java/ExampleHashInOneMethod.java
@@ -9,10 +9,9 @@
 import java.util.logging.Logger;
 
 /**
- * All in one example for hashing of a string in one method;
- * Including
+ * All in one example for hashing of a string in one method.
  * - SHA-512
- * - BASE64-encoding as representation for the byte-arrays
+ * - BASE64 encoding as representation for the byte-arrays
  * - UTF-8 encoding of String
  * - Exception handling
  */
@@ -22,14 +21,14 @@ public class ExampleHashInOneMethod {
   public static void main(String[] args) {
     String plainText = "Text that should be authenticated by comparing the hash of it!";
     try {
-      // https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#MessageDigest
+      // Get MessageDigest Instance
       MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 
       // CREATE HASH
-      byte[] hash = messageDigest.digest(plainText.getBytes(StandardCharsets.UTF_8));
+      byte[] hashBytes = messageDigest.digest(plainText.getBytes(StandardCharsets.UTF_8));
 
       // CONVERT/ENCODE IN BASE64
-      String hashString = new String(Base64.getEncoder().encode(hash),StandardCharsets.UTF_8);
+      String hashString = Base64.getEncoder().encodeToString(hashBytes);
 
       LOGGER.log(Level.INFO, hashString);
     } catch (NoSuchAlgorithmException e) {
diff --git a/src/main/java/com/cryptoexamples/java/ExampleSignatureInOneMethod.java b/src/main/java/com/cryptoexamples/java/ExampleSignatureInOneMethod.java
@@ -12,11 +12,10 @@
 import java.util.logging.Logger;
 
 /**
- * All in one example for cryptographic signing of a string in one method;
- * Including
+ * All in one example for cryptographic signing of a string in one method.
  * - Generation of public and private RSA 4096 bit keypair
  * - SHA-512 with RSA
- * - BASE64-encoding as representation for the byte-arrays
+ * - BASE64 encoding as representation for the byte-arrays
  * - UTF-8 encoding of String
  * - Exception handling
  */
@@ -38,15 +37,14 @@ public static void main(String[] args) {
       signature.update(plainText.getBytes(StandardCharsets.UTF_8));
 
       // SIGN DATA/STRING
-      byte[] signatureForPlainText = signature.sign();
-      String signatureForPlainTextString = new String(Base64.getEncoder().encode(signatureForPlainText),StandardCharsets.UTF_8);
+      String signatureForPlainTextString = Base64.getEncoder().encodeToString(signature.sign());
       LOGGER.log(Level.INFO, () -> String.format("Signature: %s", signatureForPlainTextString));
 
       // VERIFY JUST CREATED SIGNATURE USING PUBLIC KEY
       signature.initVerify(keyPair.getPublic());
       signature.update(plainText.getBytes(StandardCharsets.UTF_8));
 
-      boolean isSignatureCorrect = signature.verify(signatureForPlainText);
+      boolean isSignatureCorrect = signature.verify(Base64.getDecoder().decode(signatureForPlainTextString));
       LOGGER.log(Level.INFO, () -> String.format("Signature is correct: %b", isSignatureCorrect));
     } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
       LOGGER.log(Level.SEVERE, e.getLocalizedMessage(), e);
diff --git a/src/main/java/com/cryptoexamples/java/ExampleStringEncryptionKeyBasedInOneMethod.java b/src/main/java/com/cryptoexamples/java/ExampleStringEncryptionKeyBasedInOneMethod.java
@@ -7,6 +7,7 @@
 import javax.crypto.NoSuchPaddingException;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.GCMParameterSpec;
+import java.nio.charset.StandardCharsets;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.InvalidParameterException;
@@ -17,11 +18,11 @@
 import java.util.logging.Logger;
 
 /**
- * All in one example for encryption and decryption of a string in one method;
- * Including
+ * All in one example for encryption and decryption of a string in one method.
  * - Random key generation using strong secure random number generator
  * - AES-256 authenticated encryption using GCM
- * - BASE64-encoding as representation for the byte-arrays
+ * - BASE64 encoding as representation for the byte-arrays
+ * - UTF-8 encoding of Strings
  * - Exception handling
  */
 public class ExampleStringEncryptionKeyBasedInOneMethod {
@@ -47,18 +48,15 @@ public static void main(String[] args) {
       GCMParameterSpec spec = new GCMParameterSpec(16 * 8, nonce);
       cipher.init(Cipher.ENCRYPT_MODE, key, spec);
 
-      //byte[] aad = "Additional authenticated not encrypted data".getBytes();
-      //cipher.updateAAD(aad);
-
-      byte[] byteCipher = cipher.doFinal(plainText.getBytes());
+      byte[] byteCipher = cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
       // CONVERSION of raw bytes to BASE64 representation
-      String cipherText = new String(Base64.getEncoder().encode(byteCipher));
+      String cipherText = Base64.getEncoder().encodeToString(byteCipher);
 
       // DECRYPTION
       cipher.init(Cipher.DECRYPT_MODE, key, spec);
       //cipher.updateAAD(aad);
       byte[] decryptedCipher = cipher.doFinal(Base64.getDecoder().decode(cipherText));
-      String decryptedCipherText = new String(decryptedCipher);
+      String decryptedCipherText = new String(decryptedCipher, StandardCharsets.UTF_8);
 
       LOGGER.log(Level.INFO, () -> String.format("Decrypted and original plain text are the same: %b", decryptedCipherText.compareTo(plainText) == 0));
     } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | InvalidParameterException | InvalidAlgorithmParameterException e) {
diff --git a/src/main/java/com/cryptoexamples/java/ExampleStringEncryptionPasswordBasedInOneMethod.java b/src/main/java/com/cryptoexamples/java/ExampleStringEncryptionPasswordBasedInOneMethod.java
@@ -10,6 +10,7 @@
 import javax.crypto.spec.GCMParameterSpec;
 import javax.crypto.spec.PBEKeySpec;
 import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.InvalidParameterException;
@@ -22,13 +23,13 @@
 import java.util.logging.Logger;
 
 /**
- * All in one example for encryption and decryption of a string in one method;
- * Including
+ * All in one example for encryption and decryption of a string in one method.
  * - Random password generation using strong secure random number generator
  * - Random salt generation
  * - Key derivation using PBKDF2 HMAC SHA-256,
  * - AES-256 authenticated encryption using GCM
- * - BASE64-encoding as representation for the byte-arrays
+ * - BASE64 encoding as representation for the byte-arrays
+ * - UTF-8 encoding of Strings
  * - Exception handling
  */
 public class ExampleStringEncryptionPasswordBasedInOneMethod {
@@ -39,7 +40,6 @@ public static void main(String[] args) {
     try {
       // GENERATE password (not needed if you have a password already)
       KeyGenerator keyGen = KeyGenerator.getInstance("AES");
-      // Needs unlimited strength policy files http://www.oracle.com/technetwork/java/javase/downloads
       keyGen.init(256);
       String password = Base64.getEncoder().encodeToString(keyGen.generateKey().getEncoded());
 
@@ -50,12 +50,10 @@ public static void main(String[] args) {
 
       // DERIVE key (from password and salt)
       SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
-      // Needs unlimited strength policy files http://www.oracle.com/technetwork/java/javase/downloads
       KeySpec keyspec = new PBEKeySpec(password.toCharArray(), salt, 65536, 256);
       SecretKey tmp = factory.generateSecret(keyspec);
       SecretKey key = new SecretKeySpec(tmp.getEncoded(), "AES");
 
-
       // GENERATE random nonce (number used once)
       final byte[] nonce = new byte[32];
       random.nextBytes(nonce);
@@ -65,18 +63,14 @@ public static void main(String[] args) {
       GCMParameterSpec spec = new GCMParameterSpec(16 * 8, nonce);
       cipher.init(Cipher.ENCRYPT_MODE, key, spec);
 
-      //byte[] aad = "Additional authenticated not encrypted data".getBytes();
-      //cipher.updateAAD(aad);
-
-      byte[] byteCipher = cipher.doFinal(plainText.getBytes());
+      byte[] cipherTextBytes = cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
       // CONVERSION of raw bytes to BASE64 representation
-      String cipherText = new String(Base64.getEncoder().encode(byteCipher));
+      String cipherText = Base64.getEncoder().encodeToString(cipherTextBytes);
 
       // DECRYPTION
       cipher.init(Cipher.DECRYPT_MODE, key, spec);
-      //cipher.updateAAD(aad);
-      byte[] decryptedCipher = cipher.doFinal(Base64.getDecoder().decode(cipherText));
-      String decryptedCipherText = new String(decryptedCipher);
+      byte[] decryptedCipherTextBytes = cipher.doFinal(Base64.getDecoder().decode(cipherText));
+      String decryptedCipherText = new String(decryptedCipherTextBytes, StandardCharsets.UTF_8);
 
       LOGGER.log(Level.INFO, () -> String.format("Decrypted and original plain text are the same: %b", decryptedCipherText.compareTo(plainText) == 0));
     } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | InvalidParameterException | InvalidAlgorithmParameterException | InvalidKeySpecException e) {

Original file line number	Diff line number	Diff line change
`@@ -24,7 +24,7 @@ current_reviews: [`
`24`	`24`
`25`	`25`	`]`
`26`	`26`	`# Indicates when this example was last updated/created. Reviews don't change this.`
`27`		`-last_updated: "2018-04-28"`
	`27`	`+last_updated: "2018-05-13"`
`28`	`28`	`tags: [Java, RSA, Asymmetric, String, Encryption]`
`29`	`29`	`---`
`30`	`30`