biscuit-java vulnerable to public key confusion in third party block

A flaw in biscuit-java allows a malicious user to create a forged third-party block request that tricks the authority into trusting the wrong cryptographic key. This could lead to unauthorized token validation if the attacker convinces the authority to sign a block with incorrect key associations.

The vulnerability exists in third-party block generation where a crafted ThirdPartyBlock request can cause key confusion between the previous block's public key and keys in the token symbol table. An attacker can submit a malicious request containing mismatched public keys, causing the third-party authority to generate and sign a block with incorrect key trust relationships in the datalog rules, potentially bypassing authorization checks.