If data is not encrypted with a piece of secret information (usually a password) with enough entropy to keep it secret in the face of offline attacks, then it i

If data is not encrypted with a piece of secret information (usually a password) with enough entropy to keep it secret in the face of offline attacks, then it is as good as not encrypted, period. The hope that your hardware design is sufficiently complex and non-repairable to prevent your attacker from disassembling it and performing such an attack is not a replacement for proper encryption. And if it is encrypted with a secret with sufficient entropy, then making your hardware design non-repairable serves no reasonable purpose.