The US Postal Service has made over 600 arrests since May in an effort to combat postal crime, including mail theft and robberies targeting postal carriers. To increase security, the Postal Service is replacing universal keys with electronic locks, installing high-security blue boxes, and reducing fraudulent change-of-address transactions. The National Association of Letter Carriers has been demanding better protection for carriers, and the Postal Inspection Service is leading efforts to combat organized mail crime. The theft or assault of postal property carries severe penalties, including prison sentences ranging from 5 to 25 years.