PPU PC decrypts at a speed of 1 decryption per 1 nanosecond (ns),then a brute force attack on a 64-bit key would on average take? 2431 ns 2^32 ns 2164 ns 2463 ns None Passive attack is danger than active attack for Integrity as well as availability 2p True False All Private key cryptographic schemes based on the assumed hardness of 2 polr computational problems in number theory True O False Passive attacks easy to stop hard to detect 2 points True False