JPS59226538A - Initializing vector setting system of ciphering device - Google Patents

Abstract

PURPOSE:To shorten the delay time for data transmission by transmitting only an updating trigger signal from a transmission-side ciphering device to a reception-side ciphering device in case of transmission of communication data to make it unnecessary to transmit an initializing vector from the transmission side to the reception side. CONSTITUTION:In case of transmission of data from a station 1 to a station 2, a transmission request signal of a terminal equipment DTE1 is turned on. When this signal is detected by a ciphering device DEE1, a communication control part 1 instructs a transmission control part 3 to transmit an initializing vector updating trigger signal STA to the station 2, and an initializing vector generating part 5 is instructed to generate the initializing vector. This value is set by a cipher operating circuit 4 to obtain transmission data SD, and this signal STA is transmitted, and a switch 2 is switched from a contact (b) to a contact (a). A carrier detect signal CD transmitted from an MODEM DCE1 to an MODEM DCE2 is turned on. A communication control part 6 receives it, and a reception control part 8 receives the signal STA. The initializing vector is generated in its generating part 10, and its value is set to a pertinent operator 9 to start the operation.

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention is provided between a terminal device or a host (communication control device) (hereinafter both will be simply referred to as the terminal device DTE) and a modem (hereinafter referred to as DCE). Encryption device (hereinafter referred to as D
This relates to a method of setting an initialization vector in the EE (abbreviated as EE).

Conventional technology and problems In an encryption method for encrypting and transmitting information, communication data is encrypted on the sending side using an encryption conversion key, and the communication data is encrypted on the receiving side using a decryption key. A method is used to decode (decipher) the original communication data from the data.

FIG. 1 shows the configuration of a communication system to which the conventional system and the system of the present invention are applied. The figure shows an example of point-to-point communication, where DTEI and DTE2 are terminal devices, and DE
E.I.

DEE2 is an encryption device, DCEl, and DCE2 are modems, and the subscript 1.2 indicates each opposing station connected by a communication line. is the terminal device DT
EIO plaintext communication data is encrypted via the encryption device DEE1, converted into an appropriate modulated signal via the modem DCEI, and transmitted. On the station 2 side, the received signal is demodulated via the modem DCE2, decrypted via the encryption device DEE2, converted into plain text, and sent to the terminal device DTE2.

When transmitting information from station 2 to station 1, the signals are transmitted in the same manner in the reverse order.

In such a system, in order to encrypt communication data using an encryption conversion key on the sending side and decrypt the original communication data from the encrypted communication data using a decryption key on the receiving side, Since the conversion on the sending side and the conversion on the receiving side are performed in a synchronous relationship, the same digital pattern, that is, the initialization vector, is required on the sending and receiving sides. Therefore, when communicating, It is necessary that the required initialization vectors be set at the sender and receiver.

Conventionally, the setting of the initialization vector in the system shown in FIG.
This was done by notifying the receiving DEE from the EE.

FIG. 2 explains the timing of initialization vector setting according to the conventional procedure in the system shown in FIG. Moreover, FIG. 3 shows various control signals at this time.

In FIGS. 2 and 3, ■ is the transmission request signal R3 of the terminal device DTB1, ■ is the response signal CS from the encryption device DEEI, ■ is the communication data from the terminal device DTEI, ■ is the response signal CS from the modem DCHI, ■ indicates data on the communication line.

Now, when communication data is to be sent from the station 1 side to the station 2 side, when the terminal device DTEI turns on the transmission request signal R3, the transmission request signal R3 from the encryption device DEEI turns on. On the station 2 side, the modem DCE2 receives this via the communication line and turns on the carrier detect signal CD, which turns on the carrier detect signal CD from the encryption device 0EE2 and receives it at the terminal device DTE2. Preparations are made. On the other hand, when the modem DCEI receives the transmission request signal RS, it turns on the response signal cs. As a result, the cryptographic device DEEI first sends the initialization vector (■ν) as the transmission data SO, and then sends the initialization vector update trigger signal (ST^).
Send out. These signals are sent to the station 2 side via the modem DC[, J signal line, received via the modem DCE2, and sent to the encryption device DI! E2 Niite received data R[l (I
V), I? D (STA) is produced. Encryption device D
In EE2, an initialization vector is set using the received update trigger signal.

On the other hand, on the side, the data sent from the encryption device DEEI is SO
(IV) Upon completion of the transmission of SD (STA), the response signal CS from the encryption device DEEI turns on, and thereby the transmission data S is sent from the terminal device 111TEI.
Communication data is sent as D. In the transmission data SD shown in FIG. 3, TEXT indicates plaintext communication data. The transmission data SD is encrypted by the encryption device DEEI and transmitted as encrypted transmission data sD*. The transmitted data SD* is sent to the station 2 via the modem DCEI and the communication line, and is received by the modem DCE2 to generate encrypted received data RD*. Received data R
D* is decrypted in the encryption device DEE2 to produce plaintext received data RD that is equal to the transmitted data SO, and the received data RD is sent to the terminal device DTE2.

The data sent in this way on the communication line is
As shown in Figure 3, the initialization vector (IV), update trigger signal (STA), and encrypted communication data (CIPHERTEXT) are arranged in sequence.

In this way, in the conventional initialization vector setting method, as illustrated in FIG. 2 and FIG.
I! It was necessary to notify the receiving side cryptographic device [IEE] from E. Therefore, a data delay or a control signal delay occurs at least for the time required to transfer the initialization vector, and a circuit section for transmitting and receiving the initialization vector is required.

Purpose of the Invention The present invention aims to solve the problems of the prior art, and its purpose is to transmit only an update trigger signal from the sending cryptographic device to the receiving cryptographic device when transmitting communication data. It is an object of the present invention to provide an initialization vector setting method that eliminates the need to send an initialization vector from a transmitting side to a receiving side, thereby reducing delay time in transmitting communication data and requiring a small circuit scale.

Embodiment of the Invention FIG. 4 shows the structure of an embodiment of the system of the present invention. FIG. 5 also shows the embodiment shown in FIG.
This explains the timing of initialization vector setting in the procedure based on the method of the present invention, and FIG. 6 shows various control signals in the case of FIG. 5.

In Figure 4, only the necessary parts are shown to explain the operation when station 1 is the transmitting side and station 2 is the receiving side, but in reality, both stations 12 and 2 are transmitting data to each other. Needless to say, it is configured to be able to operate as both a receiver and receiver.

In FIG. 4, the same parts as in FIG.
liS), 5 is an initialization vector generation circuit (IVGHN
), 6 is a communication control unit (CG), 7 is a switch, 8 is a reception control unit (RCν), 9 is a cryptographic operation unit (DBS)
, 10 is an initialization vector generation circuit (IVGIEN),
11 is a switch. Also, in Fig. 5, the signal ■.

The parts indicated by ■ and ■ are the same as in the case of FIG.

When station 1 becomes a transmitter, station 1 has a terminal bag and a DTE.
When the transmission request signal R3 from I is turned off, the communication control unit 1 in the cryptographic device DEEI detects this and notifies the modem DCEI that the transmission request signal R5 is turned off, and switches the switch 2 to the b side. The OFF state of the transmission request signal R5 in the modem DCEI is transmitted to station 2, which is the receiving section, via the communication line, and therefore, on the station 2 side, the modem D
The carrier detect signal CD in CE2 is turned off, and as a result, the communication control unit 6 in the cryptographic device 0EE2
notifies the terminal device DTE2 that the carrier detect signal CD is off, switches the switch 7 to the b side, and turns off the switch 11.

When transmitting communication data from station 1 to station 2, at the start of transmission, station 1 sends the terminal device DTII! The transmission request signal RS at step 1 is turned on. When the cryptographic device DEEI detects that the transmission request signal R3 from the terminal device DTEI is turned on, the communication control unit 1 instructs the transmission control unit 3 to send an initialization vector update trigger signal STA to the station 2. , instructs the initialization vector generation unit 5 to generate an initialization vector. When the initialization vector generation unit 5 generates the initialization vector (1v), the value is sent to the cryptographic calculator 4.
, and at the same time, the communication control unit 1 instructs the cryptographic calculator 4 to start the calculation. When the transmission control unit 3 finishes transmitting the initialization vector update trigger signal STA as the transmission data SD, the communication control unit 1 switches the switch 2 from the b side to the a side.

In the station 2, when the transmission request signal RS from the modem DCEI in the station 1 is turned on, the carrier detect signal CD in the modem DCE2 is turned on. In the encryption device DEE2, when the communication control unit 6 receives the carrier detect signal C port being turned on and the reception control unit 8 receives the initialization vector update trigger signal STA via the switch 7, the communication control unit 6 transmits the terminal device DTE2. It notifies the carrier detect signal CO that the carrier detect signal CO is on, and also gives an instruction to generate an initialization vector to the initialization vector generation unit IO.

When the initialization vector generation unit 10 generates the initialization vector, it sets the value in the cryptographic calculator 9.

When the initialization vector is set, the communication control unit 6 gives an instruction to the cryptographic calculator 9 to start calculation, switches the switch 7 from the b side to the a side, and turns on the switch 11.

In station 1, when the cryptographic device DEEI finishes sending the initialization vector update trigger signal STA, it turns on the response signal C3. As a result, plaintext communication data is sent from the terminal device DTEI as transmission data SD, is encrypted by the encryption device DBHI, and the encrypted transmission data SD
* is sent to station 2 via the modem DCEI and the communication line. Station 2 receives this via modem DCE2, producing encrypted received data RD*. In the III device DHH2, the received data RD* is received by the cryptographic calculator 9 via the switch 7, and is decrypted using the set initialization vector. The decoded communication data is sent to the terminal device DTE2 via the switch 11.

At this time, the initialization vector generation section 5 of station 1, which became the transmitting section, and the initialization vector generation section 1 of station 2, which became the reception section.
0 has the same initialization vector generation function, is initialized when setting keys for encryption conversion and decryption, etc., and is mutually synchronized, and both cryptographic arithmetic units It is assumed that the same key is set in 4.9. In addition, in the above explanation, the switching timing of switch 2.7 is clearly expressed for convenience, but this means that the transmitted data from the transmitting terminal device is transmitted as the received data of the receiving terminal device, and the switching timing of switch 2.7 is clearly expressed. It is sufficient that the vector update trigger signal is transmitted to the receiving side, and there is no need to specify it in particular.

As described in detail of the invention, according to the initialization vector setting method in the cryptographic device of the present invention, the cryptographic devices on the sending side and the receiving side are provided with an initialization vector generation circuit that generates the same initialization vector, and the sending side When the cryptographic device starts transmitting data from the terminal, it sets the initial value of its initialization vector generation circuit in the cryptographic calculator to encrypt the transmitted data, and notifies the receiving cryptographic device of the initialization vector setting, and In the cryptographic device, the output value of the initialization vector generation circuit is set in the cryptographic calculator based on the notification from the transmitting side, and the received data is decrypted. It is only necessary to send an update trigger signal to the cryptographic device on the side, and there is no need to send an initialization vector from the sending side to the receiving side, which has the advantage of reducing delay time in communication data transmission and requiring a smaller circuit size. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a communication system to which the conventional method and the method of the present invention are applied, and FIG. 2 explains the timing of initialization vector setting according to the conventional procedure in the system shown in FIG. 1. FIG. 3 is a diagram showing various control signals in the procedure of FIG. 2, FIG. 4 is a diagram showing the configuration of an embodiment of the method of the present invention, and FIG. FIG. 6 is a diagram illustrating the timing of the initialization cycle setting in the procedure based on the method of the present invention in the embodiment shown in FIG. 5, and FIG. 6 is a diagram showing various control signals in the procedure shown in FIG. Old 'El, D'rE2--One terminal device or host (communication control device), DUEL, DlE2-Encryption device, DC
EI, l]cU2-・Modem, l-Communication control unit (CC)
, 2-switch, 3-transmission control unit (SNI)),
4-Crypto computing unit (DBS). 5-Initialization filter generation circuit (IVGliN),
6-Communication control unit (CC), 7-Switch, 8-Reception control unit (IICV), 9-Encryption calculator (IIES)
, 1 (1-Initialization vector generation circuit (IVGEN)
, 11-7! , Itsuchi Patent Applicant Fujitsu Limited

Claims (1)

[Claims] In a cryptographic device in which the transmitting side and the receiving side each have cryptographic processing units and the transmitting side and the receiving side encrypt and decrypt communication data using the same initialization vector, the cryptographic device on the transmitting side and the receiving side It is equipped with an initialization vector generation circuit that generates the same initialization vector, and when data transmission from the terminal starts in the sending side cryptographic device, the initial value of the initialization vector generation circuit is set in the cryptographic processing unit to encrypt the transmitted data. At the same time, the receiving cryptographic device is notified of the initialization vector setting, and the receiving cryptographic device uses the notification from the transmitting side to set the output value of the initialization vector generation circuit to the cryptographic calculator and decrypts the received data. An initialization vector setting method in a cryptographic device characterized by performing the following.