[commons-compress] 02/02: Refactor duplication and magix strings

[gg...@apache.org]

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ggregory pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-compress.git

commit 6d89cdfb3d3f5e846fd5d7082e616a5b2ab56d7c
Author: Gary Gregory <ga...@gmail.com>
AuthorDate: Sat Dec 10 22:21:07 2022 -0500

    Refactor duplication and magix strings
---
 .../compress/archivers/sevenz/AES256Options.java   | 40 +++++++++++++---------
 .../archivers/sevenz/AES256SHA256Decoder.java      |  5 ++-
 2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256Options.java b/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256Options.java
index d6bb17a8..ba23a135 100644
--- a/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256Options.java
+++ b/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256Options.java
@@ -33,9 +33,27 @@ import javax.crypto.spec.SecretKeySpec;
  */
 class AES256Options {
 
+    static final String ALGORITHM = "AES";
+
+    static final String TRANSFORMATION = "AES/CBC/NoPadding";
+
+    static SecretKeySpec newSecretKeySpec(final byte[] bytes) {
+        return new SecretKeySpec(bytes, ALGORITHM);
+    }
+    private static byte[] randomBytes(int size) {
+        byte[] bytes = new byte[size];
+        try {
+            SecureRandom.getInstanceStrong().nextBytes(bytes);
+        } catch (NoSuchAlgorithmException e) {
+            throw new IllegalStateException("No strong secure random available to generate strong AES key", e);
+        }
+        return bytes;
+    }
     private final byte[] salt;
     private final byte[] iv;
+
     private final int numCyclesPower;
+
     private final Cipher cipher;
 
     /**
@@ -59,10 +77,10 @@ class AES256Options {
 
         // NOTE: for security purposes, password is wrapped in a Cipher as soon as possible to not stay in memory
         final byte[] aesKeyBytes = AES256SHA256Decoder.sha256Password(password, numCyclesPower, salt);
-        final SecretKey aesKey = new SecretKeySpec(aesKeyBytes, "AES");
+        final SecretKey aesKey = newSecretKeySpec(aesKeyBytes);
 
         try {
-            cipher = Cipher.getInstance("AES/CBC/NoPadding");
+            cipher = Cipher.getInstance(TRANSFORMATION);
             cipher.init(Cipher.ENCRYPT_MODE, aesKey, new IvParameterSpec(iv));
         } catch (final GeneralSecurityException generalSecurityException) {
             throw new IllegalStateException(
@@ -72,6 +90,10 @@ class AES256Options {
         }
     }
 
+    Cipher getCipher() {
+        return cipher;
+    }
+
     byte[] getIv() {
         return iv;
     }
@@ -83,18 +105,4 @@ class AES256Options {
     byte[] getSalt() {
         return salt;
     }
-
-    Cipher getCipher() {
-        return cipher;
-    }
-
-    private static byte[] randomBytes(int size) {
-        byte[] bytes = new byte[size];
-        try {
-            SecureRandom.getInstanceStrong().nextBytes(bytes);
-        } catch (NoSuchAlgorithmException e) {
-            throw new IllegalStateException("No strong secure random available to generate strong AES key", e);
-        }
-        return bytes;
-    }
 }
diff --git a/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256SHA256Decoder.java b/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256SHA256Decoder.java
index 19d43443..4353bf52 100644
--- a/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256SHA256Decoder.java
+++ b/src/main/java/org/apache/commons/compress/archivers/sevenz/AES256SHA256Decoder.java
@@ -34,7 +34,6 @@ import javax.crypto.CipherInputStream;
 import javax.crypto.CipherOutputStream;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.IvParameterSpec;
-import javax.crypto.spec.SecretKeySpec;
 
 import org.apache.commons.compress.PasswordRequiredException;
 
@@ -87,9 +86,9 @@ class AES256SHA256Decoder extends AbstractCoder {
                     aesKeyBytes = sha256Password(passwordBytes, numCyclesPower, salt);
                 }
 
-                final SecretKey aesKey = new SecretKeySpec(aesKeyBytes, "AES");
+                final SecretKey aesKey = AES256Options.newSecretKeySpec(aesKeyBytes);
                 try {
-                    final Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
+                    final Cipher cipher = Cipher.getInstance(AES256Options.TRANSFORMATION);
                     cipher.init(Cipher.DECRYPT_MODE, aesKey, new IvParameterSpec(iv));
                     cipherInputStream = new CipherInputStream(in, cipher);
                     isInitialized = true;