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sasc:laboratoare:04 [2017/03/16 15:19] marios.choudary |
sasc:laboratoare:04 [2017/03/16 16:21] (current) marios.choudary |
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| We defined security of encryption scheme E against an eavesdropper in two ways: | We defined security of encryption scheme E against an eavesdropper in two ways: | ||
| - | * $Pr[A(c_b)=b] \le negl(n)$ | + | * $Pr[A(c_b)=b] \le \frac{1}{2} + negl(n)$ |
| - | * $|Pr[A(c_1)=1] - Pr[A(c_0)=1]| \le \frac{1}{2} + negl(n)$ | + | * $|Pr[A(c_1)=1] - Pr[A(c_0)=1]| \le negl(n)$ |
| where $A(c_i) = j$ means that when the adversary receives the encryption of message $i$ he returns the bit $b'=j$. | where $A(c_i) = j$ means that when the adversary receives the encryption of message $i$ he returns the bit $b'=j$. | ||
