commit 5821895ae9f9194a05d5ac11f3cec4fd0ae752ff
Author: Daniel Gultsch <daniel@gultsch.de>
Date:   Mon Mar 28 12:52:05 2016 +0200

    initial working commit

diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..2fce84f
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>eu.siacs.conversations</groupId>
+    <artifactId>ImageDownloader</artifactId>
+    <version>0.1</version>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.bouncycastle</groupId>
+            <artifactId>bcprov-jdk15on</artifactId>
+            <version>1.54</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>2.4.3</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <filters>
+                                <filter>
+                                    <artifact>*:*</artifact>
+                                    <excludes>
+                                        <exclude>META-INF/*.SF</exclude>
+                                        <exclude>META-INF/*.DSA</exclude>
+                                        <exclude>META-INF/*.RSA</exclude>
+                                    </excludes>
+                                </filter>
+                            </filters>
+                            <transformers>
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>eu.siacs.conversations.Downloader</mainClass>
+                                </transformer>
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.3</version>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>
\ No newline at end of file
diff --git a/src/main/java/eu/siacs/conversations/Downloader.java b/src/main/java/eu/siacs/conversations/Downloader.java
new file mode 100644
index 0000000..d81cc42
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/Downloader.java
@@ -0,0 +1,62 @@
+package eu.siacs.conversations;
+
+import org.bouncycastle.crypto.engines.AESEngine;
+import org.bouncycastle.crypto.io.CipherOutputStream;
+import org.bouncycastle.crypto.modes.AEADBlockCipher;
+import org.bouncycastle.crypto.modes.GCMBlockCipher;
+import org.bouncycastle.crypto.params.AEADParameters;
+import org.bouncycastle.crypto.params.KeyParameter;
+
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+public class Downloader {
+
+    public static void main(String[] args) {
+        if (args.length != 1) {
+            System.err.println("Usage: java -jar ImageDownloader.jar https://url.tld/filename#C0FFEBABE");
+        } else {
+            try {
+                final URL url = new URL(args[0]);
+                OutputStream os = setupOutputStream(new PrintStream(System.out), url.getRef());
+                final HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+                InputStream inputStream = connection.getInputStream();
+                connection.connect();
+                byte[] buffer = new byte[4096];
+                int count;
+				while ((count = inputStream.read(buffer)) != -1) {
+					os.write(buffer, 0, count);
+				}
+            } catch (Exception e) {
+                System.err.println("could not connect to host "+e.getMessage());
+            }
+        }
+    }
+
+    private static OutputStream setupOutputStream(OutputStream os, String reference) {
+        if (reference != null && reference.length() == 96) {
+            byte[] keyAndIv = hexToBytes(reference);
+            byte[] key = new byte[32];
+            byte[] iv = new byte[16];
+            System.arraycopy(keyAndIv, 0, iv, 0, 16);
+            System.arraycopy(keyAndIv, 16, key, 0, 32);
+            AEADBlockCipher cipher = new GCMBlockCipher(new AESEngine());
+            cipher.init(false, new AEADParameters(new KeyParameter(key), 128, iv));
+            return new CipherOutputStream(os, cipher);
+        } else {
+            return os;
+        }
+    }
+
+    private static byte[] hexToBytes(String hex) {
+        int len = hex.length();
+        byte[] array = new byte[len / 2];
+        for (int i = 0; i < len; i += 2) {
+            array[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4) + Character.digit(hex.charAt(i + 1), 16));
+        }
+        return array;
+    }
+}