Reputation: 2424
Encryption and decryption with a key of 128bit means that the key can't be stored in a long int variable. So what arithmetic operations exactly can be done with this key.
Upvotes: 1
Views: 272
Reputation: 42799
Let me just ask you a question back: How do you multiply or divide if you have only your brain, a pen and paper - and the number is larger than what you can compute directly using your brain?
The same scheme you use for pen and paper mathematics can be applied for numbers that are longer than the CPU register.
For certain crypto algorithms there are also optimized and specialized mathematical operations like Montgomery Multiplication for RSA
Upvotes: 2