Patent ID: 11870891
Assignee: SECURED-IC SAS
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 1:
2. The transmitter device of claim 1, wherein said identity-based cryptosystem is associated with system parameters comprising said bilinear map, said first cryptographic hash function, a second cryptographic hash function, a third cryptographic hash function, and said trusted center public key associated with the trusted center, said first ciphertext set comprising a first ciphertext, a second ciphertext, a third ciphertext, a fourth ciphertext, and a fifth ciphertext, and wherein said transmitter device is configured to:
apply the first cryptographic hash function to the receiver identifier, which provides a receiver public key;
apply a subtraction operation between (i) the second ciphertext, and (ii) the output of the second cryptographic hash function applied to the bilinear map applied to the transmitter partial private key and to the first ciphertext, which provides a secret key;
decipher the third ciphertext, which provides a recovered first public session key, said decipher using said secret key as a decryption key;
decipher the fourth ciphertext, which provides a recovered second public session key;
apply the third cryptographic hash function to said secret key, to said recovered first public session key, and to said recovered second public session key, which provides a recovered intermediate value; and
check if the fifth ciphertext is equal to the output of the second cryptographic hash function applied to an input value, said input value being the output of the bilinear map applied to (iii) the transmitter partial private key, and (iv) to the receiver public key to power said recovered intermediate value.