diff --git a/build.sbt b/build.sbt
index 3c5e465..5602a1a 100644
--- a/build.sbt
+++ b/build.sbt
@@ -82,36 +82,36 @@
 // Create executable war file
 val executableConfig = config("executable").hide
 Keys.ivyConfigurations += executableConfig
-libraryDependencies	++= Seq(
-  "org.eclipse.jetty"	%	"jetty-security"     % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-webapp"       % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-continuation" % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-server"       % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-xml"          % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-http"         % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-servlet"      % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-io"           % JettyVersion % "executable",
-  "org.eclipse.jetty"	%	"jetty-util"         % JettyVersion % "executable"
+libraryDependencies ++= Seq(
+  "org.eclipse.jetty" % "jetty-security"     % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-webapp"       % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-continuation" % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-server"       % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-xml"          % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-http"         % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-servlet"      % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-io"           % JettyVersion % "executable",
+  "org.eclipse.jetty" % "jetty-util"         % JettyVersion % "executable"
 )
 
-val executableKey	= TaskKey[File]("executable")
-executableKey	:= {
+val executableKey = TaskKey[File]("executable")
+executableKey := {
   import org.apache.ivy.util.ChecksumHelper
   import java.util.jar.{ Manifest => JarManifest }
   import java.util.jar.Attributes.{ Name => AttrName }
 
-  val workDir	= Keys.target.value / "executable"
-  val warName	= Keys.name.value + ".war"
+  val workDir   = Keys.target.value / "executable"
+  val warName   = Keys.name.value + ".war"
 
-  val log		= streams.value.log
+  val log       = streams.value.log
   log info s"building executable webapp in ${workDir}"
 
   // initialize temp directory
-  val temp	= workDir / "webapp"
+  val temp  = workDir / "webapp"
   IO delete temp
 
   // include jetty classes
-  val jettyJars	= Keys.update.value select configurationFilter(name = executableConfig.name)
+  val jettyJars = Keys.update.value select configurationFilter(name = executableConfig.name)
   jettyJars foreach { jar =>
     IO unzip (jar, temp, (name:String) =>
       (name startsWith "javax/") ||
@@ -120,31 +120,34 @@
   }
 
   // include original war file
-  val warFile	= (Keys.`package`).value
+  val warFile   = (Keys.`package`).value
   IO unzip (warFile, temp)
 
   // include launcher classes
-  val classDir		= (Keys.classDirectory in Compile).value
-  val launchClasses	= Seq("JettyLauncher.class" /*, "HttpsSupportConnector.class" */)
+  val classDir      = (Keys.classDirectory in Compile).value
+  val launchClasses = Seq("JettyLauncher.class" /*, "HttpsSupportConnector.class" */)
   launchClasses foreach { name =>
     IO copyFile (classDir / name, temp / name)
   }
 
   // zip it up
   IO delete (temp / "META-INF" / "MANIFEST.MF")
-  val contentMappings	= (temp.*** --- PathFinder(temp)).get pair relativeTo(temp)
-  val manifest		= new JarManifest
-  manifest.getMainAttributes put (AttrName.MANIFEST_VERSION,	"1.0")
-  manifest.getMainAttributes put (AttrName.MAIN_CLASS,		"JettyLauncher")
-  val outputFile		= workDir / warName
+  val contentMappings   = (temp.*** --- PathFinder(temp)).get pair relativeTo(temp)
+  val manifest          = new JarManifest
+  manifest.getMainAttributes put (AttrName.MANIFEST_VERSION,    "1.0")
+  manifest.getMainAttributes put (AttrName.MAIN_CLASS,          "JettyLauncher")
+  val outputFile    = workDir / warName
   IO jar (contentMappings, outputFile, manifest)
 
   // generate checksums
-  Seq("md5", "sha1") foreach { algorithm =>
-    IO.write(
-      workDir / (warName + "." + algorithm),
-      ChecksumHelper computeAsString (outputFile, algorithm)
-    )
+  Seq(
+    "md5"    -> "MD5",
+    "sha1"   -> "SHA-1",
+    "sha256" -> "SHA-256"
+  )
+  .foreach { case (extension, algorithm) =>
+    val checksumFile = workDir / (warName + "." + extension)
+    Checksums generate (outputFile, checksumFile, algorithm)
   }
 
   // done
@@ -153,7 +156,7 @@
 }
 /*
 Keys.artifact in (Compile, executableKey) ~= {
-	_ copy (`type` = "war", extension = "war"))
+    _ copy (`type` = "war", extension = "war"))
 }
 addArtifact(Keys.artifact in (Compile, executableKey), executableKey)
 */
diff --git a/project/Checksums.scala b/project/Checksums.scala
new file mode 100644
index 0000000..dc9d849
--- /dev/null
+++ b/project/Checksums.scala
@@ -0,0 +1,34 @@
+import java.security.MessageDigest;
+import scala.annotation._
+import sbt._
+import sbt.Using._
+
+object Checksums {
+  private val bufferSize = 2048
+
+  def generate(source:File, target:File, algorithm:String):Unit =
+      IO write (target, compute(source, algorithm))
+
+  def compute(file:File, algorithm:String):String =
+      hex(raw(file, algorithm))
+
+  def raw(file:File, algorithm:String):Array[Byte]    =
+      (Using fileInputStream file) { is =>
+        val md  = MessageDigest getInstance algorithm
+        val buf = new Array[Byte](bufferSize)
+        md.reset()
+        @tailrec
+        def loop() {
+          val len = is read buf
+          if (len != -1) {
+            md update (buf, 0, len)
+            loop()
+          }
+        }
+        loop()
+        md.digest()
+      }
+
+  def hex(bytes:Array[Byte]):String =
+      bytes map { it => "%02x" format (it.toInt & 0xff) } mkString ""
+}