Suppose we have a 2 out of 2 secret sharing scheme where Ali

Suppose we have a “2 out of 2” secret sharing scheme, where Alice and Bob share a secret S. If Trudy obtains Alice’s secret key what information can Trudy discover about S and why?

Solution

Alice and bob share a secret with a 2 out of 2 secret sharing scheme and the secret is divided into two keys and distributed among bob an alice . Now if trudy obtains alice\'s secret key then he gets the half secret as the secret is divided into two parts one part is still with bob so there is no use of alice key alone as it cannot reveal the complete secret S. For complete secret to b known to Trudy he should know both the keys of alice and bob both .