Patent ID: 11876888
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A non-transitory computer readable medium storing an encryption program which causes a computer to function as an encryption device that performs:
an acquisition process of acquiring a plaintext M;
a division process of dividing the plaintext M acquired by the acquisition process, every b bits from a beginning, the b bits being a block size of an encryption function E of a block cipher, thereby generating b-bit values M1, . . . Mm-1 and a value Mm having 1 or more bits to b or less bits;
an S1 calculation process of assigning a b-bit value H1 to a value M0, and for each integer i of i=1, . . . , m in an ascending order, taking a value Mi-1 as input to the encryption function E, thereby calculating a value S1(i), and calculating a value Ci from the value S1(i) and a value Mi;
an S2 calculation process of assigning an r-bit value H2 to a value S2(0), and for each integer i of i=1, . . . , m in an ascending order, calculating a value S2(i) from the value S1(i) calculated by the S1 calculation process and from a value S2(i−1);
a ciphertext generation process of generating a ciphertext C from a value Ci for each integer i of i=1, . . . , m; and
an authenticator generation process of generating a (b+r)-bit authenticator T by using a value S1(m) and a value S2(m).