Apparently here is a master HDCP key which can be used to subvert the entire HDCP protection system.
Paper about how this works here:
http://www.cypherpunks.ca/~iang/pubs/hdcp-drm01.pdf
Abstract. We describe a weakness in the High Bandwidth Digital Content Protection
(HDCP) scheme which may lead to practical attacks. HDCP is a proposed
identity-based cryptosystem for use over the Digital Visual Interface bus, a consumer
video bus used to connect personal computers and digital display devices.
Public/private key pairs are assigned to devices by a trusted authority, which possesses
a master secret. If an attacker can recover 40 public/private key pairs that
span the module of public keys, then the authority’s master secret can be recovered
in a few seconds. With the master secret, an attacker can eavesdrop on
communications between any two devices and can spoof any device, both in real
time. Additionally, the attacker can produce new key pairs not on any key revocation
list. Thus the attacker can completely usurp the trusted authority’s power.
Furthermore, the protocol is still insecure even if all devices’ keys are signed by
the central authority.
(HDCP) scheme which may lead to practical attacks. HDCP is a proposed
identity-based cryptosystem for use over the Digital Visual Interface bus, a consumer
video bus used to connect personal computers and digital display devices.
Public/private key pairs are assigned to devices by a trusted authority, which possesses
a master secret. If an attacker can recover 40 public/private key pairs that
span the module of public keys, then the authority’s master secret can be recovered
in a few seconds. With the master secret, an attacker can eavesdrop on
communications between any two devices and can spoof any device, both in real
time. Additionally, the attacker can produce new key pairs not on any key revocation
list. Thus the attacker can completely usurp the trusted authority’s power.
Furthermore, the protocol is still insecure even if all devices’ keys are signed by
the central authority.
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