They claim the physical copies are encrypted [1]. [1] http://blog.coinbase.com/post/33197656699/coinbase-now-storing-87-of-customer-funds-offline http://blog.c

They claim the physical copies are encrypted [1]. [1] http://blog.coinbase.com/post/33197656699/coinbase-now-storing-87-of-customer-funds-offline http://blog.coinbase.com/post/33197656699/coinbase-now-stori...