Simple algebra expression for computer encryption key length

[skram]

The total processing speed of microprocessors (based on clock rate and number of circuits) is doubling roughly every year. Today, a symmetric session key needs to be 100 bits long to be considered strong. How long will a symmetric session key have to be in 30 years to be considered strong?


Could someone please help me formulate a algebraic expression for this?

Thank you in advance!

 

[stapel]

The total processing speed of microprocessors (based on clock rate and number of circuits) is doubling roughly every year. Today, a symmetric session key needs to be 100 bits long to be considered strong. How long will a symmetric session key have to be in 30 years to be considered strong?

Could someone please help me formulate a algebraic expression for this?

How about using the compound-interest formula you learned back in algebra?

 

[skram]

Thanks y'all.. I was able to get the answer (107374182400) by applying the compound interest/future value formula.

 

[ytrewq]

Wrong

Thanks y'all.. I was able to get the answer (107374182400) by applying the compound interest/future value formula.

if you add 1 bit it doubles the number of possible keys for example 100 bits for today next year its 101. after 30 years its 130 bits... doubling the number of keys produced annually. compound interest formula is not applicable to this situation