src/Pure/General/bytes.scala

       val b = new Array[Byte](length)
       System.arraycopy(a, offset, b, 0, length)
       new Bytes(b, 0, b.length)
     }
 
-
-  def hex(s: String): Bytes =
-  {
-    def err(): Nothing = error("Malformed hexadecimal representation of bytes\n" + s)
-    val len = s.length
-    if (len % 2 != 0) err()
-
-    val n = len / 2
-    val a = new Array[Byte](n)
-    for (i <- 0 until n) {
-      val j = 2 * i
-      try { a(i) = Integer.parseInt(s.substring(j, j + 2), 16).toByte }
-      catch { case _: NumberFormatException => err() }
-    }
-    new Bytes(a, 0, n)
-  }
 
   def base64(s: String): Bytes =
   {
     val a = Base64.getDecoder.decode(s)
     new Bytes(a, 0, a.length)