JP2013191907A - Stream encryption processing system, anti-tamper device, and stream encryption processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute initialization processing for stream encryption in an anti-tamper device, to perform subsequent encryption/decryption processing by another device, and to make stream encryption algorithm hierarchical in the initialization processing.SOLUTION: An anti-tamper device includes hash function processing means of receiving a held secrete key and an initial value output from a terminal and outputting a corresponding hash value as an initial key, and initialization processing means of performing initialization processing of stream encryption on the basis of the initial key and the initial value output from the terminal, and outputting an initial status after the initialization processing to the terminal. The terminal includes stream encryption processing means of receiving the internal status input from the anti-tamper device and performing encryption or decryption processing of stream encryption.

Description

  The present invention relates to a stream encryption processing system and a stream encryption processing method, and more particularly to a stream encryption processing system, a tamper resistant device, and a stream encryption processing method for concealing a secret key used in stream encryption.

  In recent years, stream ciphers that can be processed at a higher speed than block ciphers have attracted attention. As is well known, this stream cipher is a ciphertext obtained by taking a bitwise exclusive OR with an appropriate random number of the same length from a so-called plaintext consisting of a bit string. If exclusive OR is performed with the same random number bit string as at the time of encryption, the original plaintext can be decrypted (see, for example, Patent Document 1).

JP-A-6-075524

  However, many of the stream ciphers currently in use have a risk that a secret key is derived therefrom when all internal states are stolen. On the other hand, when stream cipher is executed in a tamper-resistant device such as an IC card, there is a problem that the processing speed of encryption / decryption is reduced due to the restriction of the communication speed of the IC card.

  Accordingly, the present invention has been made in view of the above-described problems, and performs initialization processing of stream ciphers in a tamper-resistant device, performs subsequent encryption / decryption processing in another apparatus, and performs initialization. An object of the present invention is to provide a stream encryption processing system, a tamper resistant device, and a stream encryption processing method that hierarchize stream encryption algorithms.

The present invention proposes the following matters in order to solve the above problems.
(1) The present invention is a stream cipher processing system comprising a tamper resistant device and a terminal, wherein the tamper resistant device inputs a secret key held by the terminal and an initial value output from the terminal, and a corresponding hash Based on the hash function processing means for outputting the value as an initial key and the initial key and the initial value output from the terminal, the stream cipher is initialized, and the internal state after the initialization process is sent to the terminal. An initialization processing means for outputting, wherein the terminal comprises a stream cipher processing means for inputting an internal state inputted from the tamper resistant device and for performing encryption or decryption processing of the stream cipher. A stream cipher processing system is proposed.

  According to this invention, the hash function processing means of the tamper resistant device inputs the private key held and the initial value output from the terminal, and outputs the corresponding hash value as the initial key. Further, the initialization processing means performs stream cipher initialization processing based on the initial key and the initial value output from the terminal, and outputs the internal state after the initialization processing to the terminal. On the other hand, the terminal stream encryption processing means inputs the internal state input from the tamper resistant device, and performs encryption or decryption processing of the stream encryption. That is, it is possible to prevent the secret key from being easily estimated from the internal state by executing the initialization process in the tamper resistant device and further adding a one-way hash function in the initialization process. Further, by executing the encryption / decryption process at the terminal, it is possible to prevent a decrease in processing speed in the encryption / decryption process.

  (2) The present invention is a stream cipher processing system comprising a tamper resistant device and a terminal, wherein the tamper resistant device inputs a secret key held by the terminal and an initial value output from the terminal, and an initialization process And a key sequence generation means for outputting an internal state constituted by a key sequence to the terminal, wherein the terminal inputs the internal state input from the tamper resistant device and encrypts or decrypts the stream cipher. A stream cipher processing system characterized in that it comprises stream cipher processing means for performing a digitizing process has been proposed.

  According to this invention, the key sequence generation means of the tamper resistant device inputs the private key held and the initial value output from the terminal, executes the initialization process, and the internal state configured by the key sequence is changed. Output to the terminal. On the other hand, the stream encryption processing means of the terminal inputs the internal state input from the tamper resistant device, and performs stream encryption or decryption processing. That is, the initialization process is executed in the tamper resistant device, and the stream encryption algorithm is hierarchized in the initialization process, so that the secret key cannot be easily estimated from the internal state. Further, by executing the encryption / decryption process at the terminal, it is possible to prevent a decrease in processing speed in the encryption / decryption process.

  (3) The present invention is a tamper resistant device that executes stream cipher initialization processing, and combines a stored secret key with an initial value input from the outside, and outputs a corresponding hash value as an initial key. Hash function processing means for performing initialization processing for stream cipher based on the initial key and the initial value input from the outside, and outputting the internal state after the initialization processing to the outside And a tamper resistant device characterized by comprising:

  According to this invention, the hash function processing means of the tamper resistant device combines the held secret key and the initial value input from the outside, outputs the corresponding hash value as the initial key, and the initialization processing means Based on the initial key and the initial value input from the outside, the stream cipher initialization process is executed, and the internal state after the initialization process is output to the outside. Therefore, the initialization process is executed in the tamper resistant device, and the stream encryption algorithm is hierarchized in the initialization process, so that the secret key cannot be easily estimated from the internal state.

  (4) The present invention is a tamper-proof device that executes initialization processing of stream ciphers, and combines a secret key that is held with an initial value input from the outside to execute initialization processing, and a key sequence A tamper resistant device is provided, characterized by comprising key sequence generation means for outputting the internal state configured by

  According to the present invention, the key sequence generation means of the tamper resistant device combines the private key possessed with the initial value input from the outside, executes the initialization process, and sets the internal state constituted by the key sequence. Output to the outside. Therefore, the initialization process is executed in the tamper resistant device, and the stream encryption algorithm is hierarchized in the initialization process, so that the secret key cannot be easily estimated from the internal state.

  (5) The present invention provides a stream cipher processing method in a stream cipher processing system comprising a tamper resistant device and a terminal, wherein the terminal outputs an initial value to the tamper resistant device, and the tamper resistant method. A second step in which the device combines the input initial value and the private key held therein and inputs the result to the hash function; and the tamper resistant device uses the output value of the hash function as an initial key, and the initial key and the A third step of inputting an initial value input from the terminal into the stream cipher and executing an initialization process; and a fourth step in which the tamper resistant device outputs an internal state after completion of the initialization process to the terminal. A fifth step in which the terminal inputs the input internal state to the stream cipher, and the terminal performs stream cipher processing to encrypt or It proposes a stream cipher processing method characterized by comprising: a sixth step of performing No. of the.

  According to the present invention, the terminal outputs an initial value to the tamper resistant device. The tamper-proof device combines the input initial value and the private key that it holds into the hash function. In addition, the tamper resistant device uses the output value of the hash function as the initial key, inputs the initial key and the initial value input from the terminal into the stream cipher, executes the initialization process, Output the status to the terminal. On the other hand, the terminal inputs the input internal state to the stream cipher and executes stream cipher processing to perform encryption or decryption. That is, it is possible to prevent the secret key from being easily estimated from the internal state by executing the initialization process in the tamper resistant device and further adding a one-way hash function in the initialization process. Further, by executing the encryption / decryption process at the terminal, it is possible to prevent a decrease in processing speed in the encryption / decryption process.

  (6) The present invention provides a stream cipher processing method in a stream cipher processing system including a tamper resistant device and a terminal, wherein the terminal outputs an initial value to the tamper resistant device; A second step in which the device inputs the input initial value and the private key held in the stream cipher to execute an initialization process; and the tamper resistant device operates the initialized stream cipher, A third step of generating a key sequence having the same bit length; a fourth step of outputting the generated key sequence to the terminal by the tamper resistant device; and A fifth step of inputting the state into the stream cipher, and a sixth step in which the terminal performs stream cipher processing to perform encryption or decryption. It proposes a stream cipher processing method comprising the and.

  According to the present invention, the terminal outputs an initial value to the tamper resistant device. The tamper resistant device inputs the input initial value and the private key it holds into the stream cipher and executes an initialization process. Then, the initialized stream cipher is activated, a key sequence having the same bit length as the internal state is generated, and the generated key sequence is output to the terminal. On the other hand, the terminal inputs the input key sequence as an internal state to the stream cipher, and performs stream cipher processing to perform encryption or decryption. That is, the initialization process is executed in the tamper resistant device, and the stream encryption algorithm is hierarchized in the initialization process, so that the secret key cannot be easily estimated from the internal state. Further, by executing the encryption / decryption process at the terminal, it is possible to prevent a decrease in processing speed in the encryption / decryption process.

  According to the present invention, the initialization process is executed in the tamper-resistant device, and in the initialization process, a one-way hash function is added so that the secret key cannot be easily estimated from the internal state. There is an effect that can be. Further, by executing the encryption / decryption process at the terminal, there is an effect that it is possible to prevent a decrease in processing speed in the encryption / decryption process. Further, the initialization process is executed in the tamper-resistant device, and the stream encryption algorithm is hierarchized in the initialization process, thereby making it possible to prevent the secret key from being easily estimated from the internal state. is there.

It is a block diagram of the stream encryption processing system which concerns on 1st Embodiment. It is a processing flow of the stream encryption processing system which concerns on 1st Embodiment. It is a block diagram of the stream encryption processing system which concerns on 2nd Embodiment. It is a processing flow of the stream encryption processing system which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that the constituent elements in the present embodiment can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the present embodiment does not limit the contents of the invention described in the claims.

<First Embodiment>
The first embodiment will be described with reference to FIGS. 1 and 2. In this embodiment, an IC card is exemplified as a tamper resistant device and a personal computer is exemplified as a terminal. However, the present invention can be similarly applied to an IC chip and other tamper resistant devices, a mobile phone, and other terminals. It is.

<Configuration of stream cipher processing system>
As shown in FIG. 1, the stream encryption processing system according to the present embodiment includes an IC card 100 as a tamper resistant device and a personal computer (PC) 200 as a terminal. The IC card 100 includes a secret key storage unit 101, a hash function processing unit 102, and an initialization processing unit 103. A personal computer (PC) 200 includes an initial value generation unit 201 and a stream encryption processing unit 202. And.

  With such a configuration, the initialization process is executed in the tamper-resistant IC card 100 and the stream cipher encryption / decryption process is executed in the personal computer (PC) 200 having a high processing speed.

  Here, the secret key storage unit 101 in the IC card 100 stores a secret key used for the initialization process. The hash function processing unit 102 combines the initial value input from the personal computer (PC) 200 and the secret key stored in the secret key storage unit 101 to generate an initial key using a one-way hash function. The initialization processing unit 103 receives the initial key output from the hash function processing unit 102 and the initial value input from the personal computer (PC) 200, executes initialization processing by stream encryption, and sets the internal state to the personal computer. (PC) 200.

  The initial value generation unit 201 in the personal computer (PC) 200 generates an initial value necessary for the initialization process and outputs it to the IC card 100. The stream cipher processing unit 202 inputs an internal state from the IC card 100 and executes stream cipher encryption / decryption processing.

<Processing of stream cipher processing system>
Next, the processing of the stream encryption processing system according to the present embodiment will be described with reference to FIG.
First, the personal computer (PC) 200 inputs the initial value generated by the initial value generation unit 201 to the IC card 100 (step S101). The IC card 100 combines the input initial value and the secret key stored in the secret key storage unit 101 and inputs them to the hash function processing unit 102 (step S102).

  Further, the output value of the hash function processing unit 102 is used as an initial key, the initial value input from the personal computer (PC) 200 is input as an initial value to the initialization processing unit 103, and initialization processing is performed (step 103). Then, the internal state after completion of the initialization process is output to the personal computer (PC) 200 (step 104).

  On the other hand, the personal computer (PC) 200 inputs the input internal state to the stream encryption processing unit 202 (step S105), executes stream encryption, and performs encryption / decryption processing (step S106).

  Therefore, according to the present embodiment, the initialization process is executed in the tamper-resistant device (IC card 100), and further, in the initialization process, a one-way hash function is added, so that the secret key is changed from the internal state. Can not be easily estimated. Further, by executing the encryption / decryption process on the terminal (personal computer (PC) 200), it is possible to prevent a decrease in processing speed in the encryption / decryption process.

<Second Embodiment>
Next, a second embodiment will be described with reference to FIGS. 3 and 4. In this embodiment, as in the first embodiment, an IC card is exemplified as a tamper resistant device and a personal computer is exemplified as a terminal. However, an IC chip, other tamper resistant devices, a mobile phone, and other devices are described. The same applies to terminals.

<Configuration of stream cipher processing system>
As shown in FIG. 3, the stream encryption processing system according to this embodiment includes an IC card 100 as a tamper resistant device and a personal computer (PC) 200 as a terminal. The IC card 100 includes a secret key storage unit 101 and a key sequence generation unit 104, and the personal computer (PC) 200 includes an initial value generation unit 201 and a stream encryption processing unit 202.

  With such a configuration, the initialization process is executed in the tamper-resistant IC card 100 and the stream cipher encryption / decryption process is executed in the personal computer (PC) 200 having a high processing speed. In addition, about the component which attaches | subjects the same code | symbol as 1st Embodiment, since it has the same function, detailed description is abbreviate | omitted.

  Here, the key sequence generation unit 104 in the IC card 100 inputs the secret key stored in the secret key storage unit 101 and the initial value input from the personal computer (PC) 200, and performs initialization processing by stream encryption. The key sequence having the same bit length as the internal state is generated and output to the personal computer (PC) 200.

<Processing of stream cipher processing system>
Next, processing of the stream encryption processing system according to the present embodiment will be described with reference to FIG.
First, the personal computer (PC) 200 inputs the initial value generated by the initial value generation unit 201 to the IC card 100 (step S201). The IC card 100 inputs the input initial value and the secret key stored in the secret key storage unit 101 to the key sequence generation unit 104, and executes an initialization process (step S202).

  Furthermore, the key sequence generation unit 104 operates the initialized stream cipher to generate a key sequence having the same bit length as the internal state (step 203). The generated key sequence is output to the personal computer (PC) 200 (step 204).

  On the other hand, the personal computer (PC) 200 inputs the input key sequence as an internal state to the stream encryption processing unit 202 (step S205), executes stream encryption, and performs encryption / decryption processing (step S206). .

  Therefore, according to the present embodiment, the initialization process is executed in the tamper-resistant device (IC card 100), and further, in the initialization process, a one-way hash function is added, so that the secret key is changed from the internal state. Can not be easily estimated. Further, by executing the encryption / decryption process on the terminal (personal computer (PC) 200), it is possible to prevent a decrease in processing speed in the encryption / decryption process.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes designs and the like that do not depart from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... IC card, 101 ... Secret key memory | storage part, 102 ... Hash function process part, 103 ... Initialization process part, 104 ... Key sequence production | generation part, 200 ... Personal computer ( PC), 201 ... initial value generation unit, 202 ... stream cipher processing unit

Claims (6)

A stream cipher processing system comprising a tamper resistant device and a terminal,
The tamper resistant device is
A hash function processing means for inputting a secret key to be held and an initial value output from the terminal, and outputting a corresponding hash value as an initial key;
Initialization processing means for performing stream cipher initialization processing based on the initial key and the initial value output from the terminal, and outputting the internal state after the initialization processing to the terminal;
With
The terminal is
A stream cipher processing system comprising stream cipher processing means for inputting an internal state input from the tamper resistant device and performing encryption or decryption processing of the stream cipher. A stream cipher processing system comprising a tamper resistant device and a terminal,
The tamper resistant device is
A key sequence generating means for inputting a secret key to be held and an initial value output from the terminal, executing an initialization process, and outputting an internal state configured by a key sequence to the terminal,
The terminal is
A stream cipher processing system comprising stream cipher processing means for inputting an internal state input from the tamper resistant device and performing encryption or decryption processing of the stream cipher. A tamper-resistant device that performs stream cipher initialization processing,
A hash function processing means for combining a private key possessed with an initial value input from the outside and outputting a corresponding hash value as an initial key;
Initialization processing means for executing initialization processing of stream cipher based on the initial key and the initial value input from the outside, and outputting the internal state after the initialization processing to the outside;
A tamper resistant device characterized by comprising: A tamper-resistant device that performs stream cipher initialization processing,
It is characterized by comprising key sequence generation means for combining a secret key possessed with an initial value input from the outside, executing an initialization process, and outputting an internal state constituted by the key sequence to the outside Tamper resistant device. A stream cipher processing method in a stream cipher processing system comprising a tamper resistant device and a terminal,
A first step in which the terminal outputs an initial value to the tamper resistant device;
A second step in which the tamper-resistant device combines the input initial value and the private key held therein and inputs the result to the hash function;
A third step in which the tamper resistant device uses the output value of the hash function as an initial key, inputs the initial key and an initial value input from the terminal into a stream cipher, and executes an initialization process;
A fourth step in which the tamper resistant device outputs an internal state after completion of the initialization process to the terminal;
A fifth step in which the terminal inputs the input internal state to the stream cipher;
A sixth step in which the terminal performs stream encryption processing to perform encryption or decryption;
A stream encryption processing method comprising: A stream cipher processing method in a stream cipher processing system comprising a tamper resistant device and a terminal,
A first step in which the terminal outputs an initial value to the tamper resistant device;
A second step in which the tamper resistant device performs an initialization process by inputting the input initial value and the private key held in the stream cipher;
A third step in which the tamper resistant device activates the initialized stream cipher and generates a key sequence having the same bit length as the internal state;
A fourth step in which the tamper resistant device outputs the generated key sequence to the terminal;
A fifth step in which the terminal inputs the input key sequence to the stream cipher as an internal state;
A sixth step in which the terminal performs stream encryption processing to perform encryption or decryption;
A stream encryption processing method comprising:

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