Patent ID: 8275127

Claim:
An information processing apparatus, comprising: a tangible memory unit that stores key data necessary for cryptographic processing; a processor configured to execute various programs and to control starting and ending of the cryptographic processing; and an encryption processing apparatus configured to perform the cryptographic processing, the encryption processing apparatus including a first encryption processing section including a first nonlinear transformation section configured to transform first input information into first nonlinear transformed information, and a first linear transformation section configured to transform the first nonlinear transformed information into first linear transformed information; a second encryption processing section including a second nonlinear transformation section configured to transform second input information into second nonlinear transformed information, and a second linear transformation section configured to transform the second nonlinear transformed information into second linear transformed information; an exclusive-or section configured to perform an exclusive-or operation based on the second linear transformed information and the first linear transformed information, wherein when the first nonlinear transformed information is expressed as a first sequence vector, the first linear transformed information is expressed as a second sequence vector, the second nonlinear transformed information is expressed as a third sequence vector, and the second linear transformed information is expressed as a fourth sequence vector, then (1) a first row vector chosen from a first inverse matrix of a first matrix that transforms the first sequence vector to the second sequence vector, and (2) a second row vector chosen from a second inverse matrix of a second matrix that transforms the third sequence vector to the fourth sequence vector, are linearly independent.