A shuffle with proof having a method for proof generating with small computational
resources proportionate to the number of input encrypted messages and a corresponding
method for verification. Shuffle is represented by a generalized transformation.
Combining a proof that the transformation information is retained and a proof of
a condition under which the transformation is met constitute the proof for shuffle.
The two proofs are short proportional to the number of input encrypted messages.
Transformation information retention is proved in such a manner that, since the
response is generated from challenge value in dependency upon transformation, the
condition under which the transformation is met is reflected in the response-challenge
value relation. If the condition under which the transformation corresponding to
the shuffle is selected as the condition for proof, the two proofs may constitute
the proof for shuffle.