Communication methods and systems

Abstract

A communication method and a communication system are provided that can further improve the confidentiality and integrity of communication compared to conventional methods. [Solution] In this embodiment, the certification infrastructure used to establish and operate the encrypted communication channel 5a and the certification infrastructure used in the application layer signature process and application layer encryption process are based on mutually independent trust infrastructures with different certificate authorities or root certificates as the origin of trust. Therefore, even if a vulnerability occurs in the certificate or certificate authority of the encrypted communication channel 5a, the message-level cryptographic protection based on JWS signatures and JWE encryption is not affected. Conversely, even if a breach occurs in the application layer key management system, outer layer encryption by the encrypted communication channel 5a is maintained, ensuring protection of the entire communication channel.

Description

[Technical Field]

[0001] The present invention relates to a communication method and a communication system. [Background technology]

[0002] In communications via the Internet, encrypted communications using TLS (Transport Layer Security) are widely used to prevent eavesdropping and tampering of communication content (see, for example, Patent Document 1). Also, in the application layer, a configuration has been proposed in which signatures and encryption are performed on a communication message basis (see, for example, Patent Document 2), which can increase the integrity of communication data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4431112 [Patent Document 2] Patent No. 7389754 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if TLS communication is simply used in conjunction with standard methods such as JWS (JSON Web Signature) and JWE (JSON Web Encryption), which sign and encrypt individual communication messages, vulnerabilities may still remain. Therefore, there is a need for the development of new communication technologies that can further improve the confidentiality and integrity of communications.

[0005] In view of the above problems, it is an object of the present invention to provide a communication method and a communication system that can further improve the confidentiality and integrity of communications compared to conventional methods. [Means for solving the problem]

[0006] The communication method of the present invention is a communication method for communicating between communication units in a communication system, and comprises: an establishment step of performing a TLS handshake between the communication units to generate a common key and establish an encrypted communication path using TLS; a message generation step in which one of the communication units generates a message including application data to be communicated; an application layer signing step of attaching a JWS signature to the message based on a first key pair; an application layer encryption step of JWE-encrypting the JWS-signed message based on a second key pair to generate a JWE-encrypted message; a transmission step of transmitting the JWE-encrypted message to the other communication unit via the encrypted communication path; and a decryption and verification step in which the receiving communication unit decrypts the encrypted message received via the encrypted communication path and verifies the JWS signature.The certification infrastructure used in the establishment and operation of the encrypted communication path and the certification infrastructure used in the application layer signing step and the application layer encryption step are based on mutually independent trust infrastructures with different certification authorities or root certificates as the origin of trust, thereby achieving threat countermeasures through multi-layer defense.

[0007] In addition, the communication system of the present invention is a communication system for communication between communication units, and comprises: an establishment unit that performs a TLS handshake between the communication units to generate a common key and establish an encrypted communication path using TLS; a message generation unit in which one of the communication units generates a message including application data to be communicated; an application layer signature unit that assigns a JWS signature to the message based on a first key pair; an application layer encryption unit that JWE-encrypts the JWS-signed message based on a second key pair to generate a JWE-encrypted message; a transmission unit that transmits the JWE-encrypted message to the other communication unit via the encrypted communication path; and a decryption verification unit in which the receiving communication unit decrypts the encrypted message received via the encrypted communication path and verifies the JWS signature; and the certification infrastructure used in the establishment and operation of the encrypted communication path and the certification infrastructure used by the application layer signature unit and the application layer encryption unit are based on mutually independent trust infrastructures with different certification authorities or root certificates that serve as the origin of trust, thereby achieving threat countermeasures through multi-layered defense. [Effects of the Invention]

[0008] According to the present invention, rather than simply combining an encrypted communication channel using TLS with message-level encryption using JWS signatures and JWE encryption, the proof infrastructure used for the encrypted communication channel and the proof infrastructure used for JWS signatures and JWE encryption are configured to be independent from each other. This allows for multi-layered protection of communication data, and even if a problem occurs in one trust infrastructure, it is unlikely to affect the other, further improving the confidentiality and integrity of communications. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a communication system. [Figure 2] FIG. 2 is a block diagram showing the configuration of a communication unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will now be described with reference to FIG.

[0011] (1) Overall configuration of the communication system 1, a communication system 1 according to this embodiment includes a transmitting unit 2a, a relay unit 2b, and a receiving unit 2c. The transmitting unit 2a, the relay unit 2b, and the receiving unit 2c are connected to each other via a network (not shown), such as the Internet, and communicate with each other. In this embodiment, for ease of explanation, the transmitting unit 2a, the relay unit 2b, and the receiving unit 2c are assumed to have the same configuration, and when no distinction is made between the transmitting unit 2a, the relay unit 2b, and the receiving unit 2c, they will be simply referred to as communication units 2.

[0012] The transmitting unit 2a according to this embodiment is, for example, a server device, and is responsible for generating and transmitting messages including application data. The receiving unit 2c is, for example, a client device, and receives encrypted messages transmitted from the transmitting unit 2a and performs decryption and signature verification. The relay unit 2b is a device that relays communication between the transmitting unit 2a and the receiving unit 2c, and is configured as, for example, a gateway device or a proxy server. A configuration may also be adopted in which the transmitting unit 2a and the receiving unit 2c transmit and receive directly via a network, without providing the relay unit 2b.

[0013] In this embodiment, a server device and a client device are communication units 2, and the present invention is applied to communication between the server device and the client device, but the present invention is not limited to this. For example, software components that operate independently of each other within the same device may be communication units, and the present invention may be applied to communication between these software components.

[0014] Between the sending unit 2a and the receiving unit 2c, an encrypted communication path 5a using TLS (Transport Layer Security) as an outer layer communication path, and an application layer (including message layer) encrypted communication path 5b as an inner layer communication path are formed. The "outer layer communication path" refers to a communication path established between communication units 2 using TLS and conforming to the transport layer encryption protocol. In other words, the outer layer communication path is an encrypted communication path in the transport layer that encrypts the entire communication path and prevents eavesdropping and tampering on the data transmission path.

[0015] Here, the encrypted communication channel 5a using TLS refers to an encrypted communication channel established by the TLS protocol or an equivalent encrypted communication technology. The TLS-equivalent encrypted communication technology includes DTLS (Datagram Transport Layer Security), which implements TLS on UDP, and QUIC (Quick UDP Internet Connections), which integrates TLS 1.3. The encrypted communication channel 5a using TLS encrypts the entire communication channel to prevent eavesdropping and tampering.

[0016] Note that the communication system 1 according to this embodiment may be configured to employ mutual TLS authentication (mTLS) in which both the client and server authenticate each other using certificates when using TLS communication. Compared to one-way authentication using only a server certificate (normal HTTPS communication), mTLS allows both ends of the communication to mutually verify legitimacy, thereby preventing spoofing and improving reliability. Establishing such an encrypted communication path using mTLS is one embodiment of establishing an encrypted communication path 5a using TLS.

[0017] On the other hand, the application layer encrypted communication channel 5b, which is an inner layer communication channel, ensures confidentiality and integrity on a message-by-message basis by applying JWS (JSON Web Signature) signatures and JWE (JSON Web Encryption) encryption to messages sent and received on the encrypted communication channel 5a. This configuration based on mutually independent trust infrastructures is a diverse threat countermeasure that combines different security mechanisms, and realizes robust communication defense through so-called defense in depth.

[0018] "Inner layer communication path" refers to an encrypted communication path in the application layer (including the message layer) using JWS signatures and JWE encryption applied to messages containing application data sent and received over an encrypted communication path 5a using TLS.

[0019] Note that the JWS signature and JWE encryption in this embodiment may be applied to both request and response messages, thereby ensuring the integrity and confidentiality of each message for both request messages and response messages exchanged between communication units 2.

[0020] In addition to this configuration, the communication system 1 of this embodiment does not simply combine an encrypted communication path 5a using TLS with message-level encryption using JWS signatures and JWE encryption, but is configured such that the certification infrastructure (PKI (Public Key Infrastructure)) used for the encrypted communication path 5a and the certification infrastructure (PKI) used for JWS signatures and JWE encryption are mutually independent.

[0021] That is, the certification infrastructure used to establish and operate the encrypted communication channel 5a is generally based on a server certificate issued by a public Certificate Authority (CA), an intermediate CA certificate (if necessary), and a root certificate.

[0022] Note that the certificate system may be operated hierarchically depending on the type and configuration of communication. For example, a primary certificate system applicable to communication across network boundaries may be adopted for communication between communication units 2 or between zones, and an independent secondary certificate system may be adopted for communication between software components within the same device. This allows a different trust base to be assigned to each network layer, further improving the operability and security of the entire communication system 1.

[0023] On the other hand, the proof infrastructure used for JWS signatures and JWE encryption is based on a certification authority established independently by the operator of the communication system 1 (the organization that operates the communication system) or the device manufacturer (e.g., the manufacturer of the communication unit 2), or on key pairs and certificates generated and managed by a tamper-resistant hardware security module (HSM) or trusted platform module (TPM).

[0024] As described above, in the communication system 1 according to the present embodiment, the certification infrastructure for the encrypted communication path 5a using TLS and the certification infrastructure for the JWS signature / JWE encryption are operated as independent systems that each have a different certificate authority or root certificate as the origin of trust. Therefore, even if a vulnerability or fraud occurs in one of the trust infrastructures, it is unlikely to affect the communication protection function of the other encrypted communication path 5a or application layer encrypted communication path 5b, and the reliability and security strength of the communication system 1 as a whole can be significantly improved.

[0025] This configuration also allows for, for example, the updating and reissuing of certificates for the encrypted communication path 5a to be operated independently of the application layer signing key management, enabling flexible configuration changes according to security policies and operational environments, and achieving diverse threat countermeasures in that they can be operated independently based on different technical principles. This is particularly useful in distributed systems and cloud environments where multiple telecommunications carriers and service providers work together.

[0026] (2) Communication unit configuration Next, we will explain the configuration of the communication unit 2. The communication unit 2 is configured with one or more processors such as a CPU (Central Processing Unit), and executes an OS (Operating System), a communication processing program of the present invention, and other applications stored in a memory (not shown), thereby controlling various circuits in the communication unit 2 and performing predetermined processing.

[0027] As shown in FIG. 2, the communication unit 2 includes a transceiver 10, an establishment unit 11, a message generator 12, an application layer signature unit 13, an application layer encryption unit 14, a decryption verification unit 15, a certificate manager 16, and an application layer key manager 17. The transceiver 10 functions as a transmitter and a receiver. The transceiver 10 is a communication interface that transmits and receives data to and from other communication units 2. The transceiver 10 outputs data received from other communication units 2 to each circuit unit as needed. The establishment unit 11 has the function of performing a TLS handshake with other communication units 2 to generate a common key and establish an encrypted communication path 5a using TLS. This encrypts the entire communication path between the communication units 2, preventing eavesdropping and tampering. The transceiver 10 transmits and receives encrypted messages via the encrypted communication path 5a established by the establishment unit 11.

[0028] Message generator 12 generates a message including application data to be communicated. The generated message is signed and encrypted by application layer signature unit 13 and application layer encryption unit 14, which will be described later.

[0029] Application layer signature unit 13 executes a signature calculation and assigns a JWS signature based on the first key pair to the message generated by message generation unit 12. The JWS signature allows communication unit 2 on the message receiving side to verify whether the message has been tampered with and the legitimacy of the sender.

[0030] Application layer encryption unit 14 executes encryption processing and JWE-encrypts the message to which the JWS signature has been added by application layer signature unit 13, based on the second key pair. This allows the contents of the application data to be encrypted on a message-by-message basis, ensuring confidentiality.

[0031] The decryption verification unit 15 decrypts the encrypted message generated by the communication unit 2 on the other side of communication and received via the transmission / reception unit 10, and verifies the JWS signature. This allows the communication unit 2 on the receiving side to detect tampering and confirm the legitimacy of the received message.

[0032] The certificate management unit (outer layer (transport layer) certificate management unit) 16 manages certificates used in the establishment and operation of the encrypted communication channel 5a. Specifically, the certificate management unit 16 holds server certificates, root certificates, and certificate revocation information (CRL: Certificate Revocation List, OCSP information, etc.), and supports the authentication process during the TLS handshake by the establishment unit 11. The certificate management unit 16 performs processes related to the holding, verification, validity check, and update management of certificates used in the establishment and operation of the encrypted communication channel 5a using TLS, based on a certificate system including server certificates and root certificates issued by a public certification authority (CA).

[0033] On the other hand, application layer key management unit 17 manages key pairs and related certificate information used for JWS signature and JWE encryption. Specifically, application layer key management unit 17 generates a first key and a second key used in the signature process and encryption process, stores these keys, and provides them to application layer signature unit 13 and application layer encryption unit 14 as needed.

[0034] The application layer key management unit 17 may be configured to use keys generated and stored by a certification authority established independently by the operator or device manufacturer of the communication system 1, or by a tamper-resistant hardware security module (HSM) or trusted platform module (TPM). The application layer key management unit 17 may be configured to incorporate an HSM or TPM. In this case, the application layer key management unit 17 controls the HSM or TPM to request key generation, issue instructions for signature or encryption processing, and manage key update or revocation, thereby comprehensively managing the lifecycle of keys in the application layer. This enables logical key management and physical key protection to be integrated, further improving the reliability and security of the communication system 1.

[0035] The keys managed by the application layer key management unit 17 may be used for client signatures that comply with WebAuthn (Web Authentication). In this case, the identity of the client device or user can be guaranteed on a message-by-message basis using a private key stored in secure hardware such as a Trusted Platform Module (TPM), enabling further strengthened authentication.

[0036] In this way, the communication unit 2 of this embodiment is equipped with both a configuration for establishing an encrypted communication path 5a, which is an outer layer communication path, and a configuration for performing JWS signature and JWE encryption at the application layer, thereby realizing double cryptographic protection based on different, mutually independent trust bases.

[0037] (3) Action and effect As described above, the communication method executed in the communication system 1 according to this embodiment is such that the establishing unit 11 executes a TLS handshake between the communication units 2 to generate a common key and establishes an encrypted communication path 5a using TLS (establishment step). As a result, the encrypted communication path 5a using TLS is established, the entire communication path between the communication units 2 is encrypted, and eavesdropping and tampering can be prevented by the encrypted communication path 5a.

[0038] Next, message generation unit 12 generates a message including application data to be communicated by one of communication units 2 (message generation step), and application layer signature unit 13 assigns a JWS signature to the message based on the first key pair (application layer signature step). Next, application layer encryption unit 14 JWE-encrypts the message with the JWS signature based on the second key pair to generate a JWE-encrypted message (application layer encryption step).

[0039] Next, the sending unit 2a (server device) transmits the JWE encrypted message to the other communication unit 2 via the encrypted communication path 5a using the sending / receiving unit 10 (sending step). As a result, the receiving unit 2c (client device) decrypts the encrypted message received via the encrypted communication path 5a using the decryption verification unit 15 and verifies the JWS signature (decryption verification step). As a result, by verifying the JWS signature, the receiving unit 2c can detect tampering of the received message and confirm the legitimacy of the sender.

[0040] In this embodiment, the certification infrastructure used to establish and operate the encrypted communication path 5a and the certification infrastructure used in the application layer signature process and application layer encryption process are based on mutually independent trust infrastructures, each with a different certificate authority or root certificate as the origin of trust. Therefore, even if a vulnerability occurs in the certificate or certificate authority of the encrypted communication path 5a, the message-level cryptographic protection based on JWS signatures and JWE encryption is not affected. Conversely, even if a breach occurs in the application layer key management system, the outer layer encryption of the encrypted communication path 5a is maintained, ensuring protection of the entire communication path.

[0041] In this manner, in this embodiment, the same communication data is protected by multiple different encryption layers using the encrypted communication channel 5a, the JWS signature, and the JWE encryption, so that even if the encrypted communication channel 5a is compromised, the confidentiality and integrity of the communication data are maintained by the JWS signature and the JWE encryption. Furthermore, by combining various encryption technologies and independent authentication systems in this manner, the communication system 1 can achieve robust threat countermeasures based on the principle of defense in depth.

[0042] According to the communication system 1 of this embodiment, the transport layer encrypted communication path 5a and the application layer JWS / JWE encrypted communication function in cooperation with each other, thereby doubly encrypting and protecting communication data. In particular, because the two are operated based on different trust infrastructures, even if vulnerabilities or fraud occur in one of the infrastructures, the protection function of the other communication layer is maintained. As a result, the confidentiality and integrity of the entire communication can be further improved compared to conventional methods. Furthermore, the independence of the encrypted communication path 5a and the application layer encrypted communication path 5b in the communication system 1 of this embodiment enables a diversified configuration that combines different algorithms, certification authorities, or operational domains for each defense layer. As a result, the communication system 1 of this embodiment can build a flexible multi-layer defense system that is not dependent on a specific encryption method or operational infrastructure.

[0043] Furthermore, because the encrypted communication path 5a and JWS / JWE encryption are hierarchically independent, certificates and keys can be managed and updated separately for each trust infrastructure, which allows for flexible configuration changes according to security policies and operational environments, improving the operability of the communication system 1.

[0044] (4) Other embodiments It is preferable that at least one of the first key pair or the second key pair is generated by a tamper-resistant hardware security module or a trusted platform module and held in the application layer key management unit 17.

[0045] Furthermore, the sharing or distribution of encryption keys in JWE encryption may be achieved by a key exchange method using an ephemeral key pair generated for each session. With this configuration, encrypted communication based on a one-time key is established for each session, and even if some key information is leaked, the scope of the impact can be limited to that session. Therefore, the confidentiality and security of key management of the entire communication system 1 can be further improved. [Explanation of symbols]

[0046] 1. Communication Systems 2, 2a Transmission unit (communication unit) 2, 2c Receiving unit (communication unit) 10 Transmitter / receiver (transmitter) 11 Establishment Department 12 Message Generation Unit 13 Application Layer Signature 14 Application Layer Encryption 15 Decryption Verification Unit

Claims

1. A communication method for communicating between communication units in a communication system, comprising: an establishing step of performing a TLS handshake between the communication units to generate a common key and establish an encrypted communication path using TLS; a message generation step in which one of the communication units generates a message including application data to be communicated; an application layer signing step of applying a JWS signature to the message based on a first key pair; an application layer encryption step of JWE-encrypting the JWS-signed message based on a second key pair to generate a JWE-encrypted message; a transmitting step of transmitting the JWE encrypted message to the other communication unit via the encrypted communication path; a decryption verification step in which the communication unit on the receiving side decrypts the encrypted message received through the encrypted communication path and verifies the JWS signature; Equipped with A communication method in which the certification infrastructure used to establish and operate the encrypted communication path and the certification infrastructure used in the application layer signature process and the application layer encryption process are based on mutually independent trust infrastructures with different certification authorities or root certificates as the source of trust, thereby achieving threat countermeasures through multi-layered defense.

2. At least one of the first key pair or the second key pair is generated by a tamper-resistant hardware security module or a trusted platform module and stored in the communication unit; The communication system according to claim 1 .

3. The certification infrastructure used to establish and operate the encrypted communication path is based on a certificate issued by a public certification authority, the certification infrastructure used in the application layer signing step and the application layer encryption step is based on a unique certification authority managed by an organization operating the communication system or a device manufacturer; The communication system according to claim 1 .

4. The encrypted communication channel and the JWE encryption protect the same communication data with multiple different encryption layers, and even if the encrypted communication channel is compromised, the confidentiality and integrity of the communication data are maintained by the JWS signature and the JWE encryption. The communication system according to claim 1 .

5. A communication system for performing communication between communication units, an establishment unit that executes a TLS handshake between the communication units to generate a common key and establish an encrypted communication path using TLS; a message generating unit for generating a message including application data to be communicated by one of the communication units; an application layer signature unit that assigns a JWS signature to the message based on a first key pair; an application layer encryption unit that JWE-encrypts the JWS-signed message based on a second key pair to generate a JWE-encrypted message; a transmitting unit that transmits the JWE encrypted message to the other communication unit via the encrypted communication path; a decryption verification unit configured to decrypt the encrypted message received through the encrypted communication channel and verify the JWS signature; Equipped with A communications system in which the certification infrastructure used to establish and operate the encrypted communication path and the certification infrastructure used in the application layer signature unit and the application layer encryption unit are based on mutually independent trust infrastructures with different certification authorities or root certificates that serve as the source of trust, thereby realizing threat countermeasures through multi-layered defense.

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