Fixes for decryption of empty files.

Author: tchudyk

README.MD

@@ -22,7 +22,7 @@ Add dependency:
 <dependency>
     <groupId>com.github.tchudyk</groupId>
     <artifactId>filetype-aes</artifactId>
-    <version>1.0.1</version>
+    <version>1.0.2</version>
 </dependency>
 ```
 

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>pl.codeset</groupId>
     <artifactId>filetype-aes</artifactId>
-    <version>1.0.1</version>
+    <version>1.0.2</version>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

src/main/java/pl/codeset/aesfiletype/AesReader.java

@@ -124,8 +124,10 @@ void decrypt(OutputStream outputStream) throws IOException {
                 bytesRead += read.length;
                 readPayload += read.length;
 
-                cipher.update(read, 0, BLOCK_SIZE, decrypted);
-                hmac.update(read, 0, BLOCK_SIZE);
+                if (read.length > 0) {
+                    cipher.update(read, 0, BLOCK_SIZE, decrypted);
+                    hmac.update(read, 0, BLOCK_SIZE);
+                }
 
                 int readLength = read.length;
                 if (readPayload >= expectedPayloadSize) {
@@ -134,7 +136,9 @@ void decrypt(OutputStream outputStream) throws IOException {
                     readLength = (last > 0 ? last : BLOCK_SIZE);
                 }
 
-                outputStream.write(decrypted, 0, readLength);
+                if (read.length > 0) {
+                    outputStream.write(decrypted, 0, readLength);
+                }
             } while (readPayload < expectedPayloadSize);
 
             outputStream.write(cipher.doFinal());

src/test/java/pl/codeset/aesfiletype/AesFileTest.java

@@ -26,4 +26,21 @@ void encryptDecryptTest(@TempDir Path tempDir) {
 
         assertArrayEquals(inputBytes, bytes);
     }
+
+    @Test
+    void encryptDecryptEmptyTest(@TempDir Path tempDir) {
+
+        byte[] inputBytes = "".getBytes(StandardCharsets.UTF_8);
+        AesFileBuilder.fromBytes(inputBytes)
+                .usePassword("test")
+                .writeToFile(tempDir.resolve("encrypted.aes"))
+                .build();
+
+        AesFile loadedFile = AesFile.openFromFile(tempDir.resolve("encrypted.aes"))
+                .usePassword("test");
+
+        byte[] bytes = loadedFile.decryptToBytes();
+
+        assertArrayEquals(inputBytes, bytes);
+    }
 }