LEAF field encryption

[smb at research.att.com]

As promised, I asked Steve Kent -- a member of the review panel -- about
how the LEAF is encrypted.  Here's his answer, reposted with permission.

------- Forwarded Message

To: smb at research.att.com
Subject: Re: Key escrow review 
In-reply-to: Your message of Mon, 14 Mar 94 15:54:22 -0500.
Date: Mon, 14 Mar 94 17:03:18 -0500
From: Steve Kent <kent at BBN.COM>

Steve,

You are right....  SKIPJACK is used to encipher the LEAF, but employing
a complex mode.  The FBI can decode the "outer layer" of the LEAF to
get the chip ID, by using the "family key" but it cannot get at the
traffic key which is encrpted using the device unique key, the splits
for which are held by the escrow agents.

Steve

------- End of Forwarded Message