Question Consider a variant of the one-time pad with message space {0,1}n , where the key space is restricted to all n-bit strings with an even number of 1’s. Prove that this cipher is not secure by showing an adversary whose semantic security advantage is 1.

FDAFAF The Asker · Computer Science

Consider a variant of the one-time pad with message space {0,1}n , where the key space is restricted to all n-bit strings with an even number of 1’s. Prove that this cipher is not secure by showing an adversary whose semantic security advantage is 1.

Transcribed Image Text: Consider a variant of the one-time pad with message space {0,1}n , where the key space is restricted to all n-bit strings with an even number of 1’s. Prove that this cipher is not secure by showing an adversary whose semantic security advantage is 1.
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Transcribed Image Text: Consider a variant of the one-time pad with message space {0,1}n , where the key space is restricted to all n-bit strings with an even number of 1’s. Prove that this cipher is not secure by showing an adversary whose semantic security advantage is 1.
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TPXET3

&#160; &#160;Our One Time Pad(OTP)is secure and that the chance of&#160;AA&#160;to succeedis&#160;2&#8722;n2&#8722;n&#160;(for&#160;INFO(1n,m)=mINFO(1n,m)=m),because&#160;SS&#160;also has a chance of&#160;2&#8722;n2&#8722;n&#160;to pickthe correct binary string. But as we are tryingto&#160;proove&#160;the security, we can't argue that way.And as soon as we can no longer use that knowledge, the proof nolonger works.semantic security of the one ... See the full answer