Are there any forms of encryption which take a predictable and precisely defined amount of computing power to decrypt?
e.g. Some asymmetric so that I could encrypt something easily but then require someone who wants to decrypt the message to perform 100 Trillion operations to decrypt it?
It's almost always probabilistic - someone guessing the right key the first time could break it very quickly.
It may be possible to reduce variance in cracking times by requiring multiple cracks (use a secret sharing scheme to break up the "real" key in chunks; encrypt each chunk in a crackable way.)
e.g. Some asymmetric so that I could encrypt something easily but then require someone who wants to decrypt the message to perform 100 Trillion operations to decrypt it?