The P1735 IEEE standard describes flawed methods for encrypting electronic-design intellectual property (IP), as well as the management of access rights for such IP, including modification of encrypted IP cyphertext to insert hardware trojans. The methods are flawed and, in the most egregious cases, enable attack vectors that allow recovery of the entire underlying plaintext IP. Implementations of IEEE P1735 may be weak to cryptographic attacks that allow an attacker to obtain plaintext intellectual property without the key, among other impacts.