Java Security

Is there a way to decrypt SHA1? I have encrypted SOAP message's UsernameToken password:

 String sha1Hash = null;
	  try {
	    MessageDigest md = MessageDigest.getInstance("SHA1");
	    byte[] digest = md.digest(text.getBytes());
	    sha1Hash = new String(Base64.encode(digest));
	  } catch (Exception e) {
	    e.printStackTrace();
	  }