Cryptographic Binding for Encryptor Authenticity
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Solution Overview
Problem
Existing digital signature algorithms do not guarantee that the encryptor of encrypted data and the generator of the signature are the same party, leaving online payment systems vulnerable to attacks where an attacker can intercept and re-sign encrypted data.
Innovation Solution
Cryptographically binding the signature and encryption processes by using one or more signing public keys in the key derivation process for symmetric encryption, ensuring that only the same party can generate valid signatures for encrypted data, thereby verifying the authenticity of the encryptor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signature algorithms are used to verify message authenticity, then the signature verification provides strong indication that the message was created by a known sender, but it does not guarantee that the encryptor of the cyphertext and the generator of the signature are the same party
Solution Approach 1:
The patent merges the signature generation and encryption processes by requiring that the same private key be used for both operations. The signature is generated over the encrypted cyphertext, creating a cryptographic binding between the encryptor and the signer. This ensures that the entity that encrypted the data is the same entity that signed it, preventing attacks where an attacker could intercept and re-sign encrypted data with a different key.
2Reliability
If separate encryption and signature processes are used, then the encryption provides confidentiality and the signature provides authentication, but the system becomes vulnerable to attacks where an attacker can intercept and re-sign encrypted data
Solution Approach 1:
The patent applies preliminary anti-action by pre-establishing a cryptographic binding between encryption and signature operations. Before any attack can occur, the system ensures that the same private key is used for both encryption and signature generation. This preliminary measure prevents attackers from successfully intercepting and re-signing encrypted data, as they would need to possess the same private key used for encryption, which is computationally infeasible to obtain.
3Reliability
If the same private key is used for both encryption and signature generation, then the encryptor and signer are guaranteed to be the same party, but the key management complexity increases
Solution Approach 1:
The patent applies universality by designing a cryptographic system where a single private key serves multiple functions: it is used both for generating the symmetric encryption key (through key derivation) and for generating the digital signature. This multi-functional approach ensures encryptor-signer identity guarantee while actually simplifying key management, as only one private key needs to be securely stored and managed rather than multiple separate keys.
Data Source
AI summary
Embodiments described herein provide cryptographic techniques to enable a recipient of a signed message containing encrypted data to verify that the signer of the message and the encryptor of the encrypted data are the same party, or at the least, have joint possession of a common set of secret cryptographic material. These techniques can be used to harden an online payment system against interception and resigning of encrypted payment information.