An obfuscation circuit relies on a tamper-resistant nonvolatile memory which encodes a trusted Boolean function. The Boolean function is used to enable several operations relating to circuit obfuscation, including obfuscation of logic circuitry, obfuscation of operand data, and release of IP blocks. The tamper-resistant nonvolatile memory is part of a trusted integrated circuit structure, i.e., one fabricated by a trusted foundry, separate from another integrated circuit structure which contains the various operational logic circuits of the design and is fabricated by an untrusted foundry. The Boolean function is encoded based on a look-up table implemented as a cascaded multiplexer circuit. Multiple obfuscation functions can be so encoded. The obfuscation functions may be reprogrammed using a protocol that relies on symmetric keys, one of which is stored in the tamper-resistant nonvolatile memory.