IACR News item: 26 June 2023
Sai Sandilya Konduru, Vishal Saraswat
ePrint Report
Healthcare providers cannot share their patients' encrypted
data among themselves because of interoperability issues. Many blockchain-
based solutions have been proposed to allow for sharing medical data in
a privacy-preserving manner, but interoperability problems persist.
In this paper, we present a protocol called Blockchain-Format Preserving
Encryption (B-FPE) to preserve patients' data privacy. Each patient is
provided with an FPE key at the time of registration. All medical
records are encrypted with the FPE key and stored in the blockchain. All
the blockchain transactions are signed using group signatures. We use
group signatures for signing the transactions to maintain the anonymity
of healthcare providers. The new encrypted data block is concatenated to
the blockchain. We present two cases: The regular phase, in which a patient is
in a conscious state to share their FPE key with the healthcare provider, and the Emergency phase, in which a patient is not in a conscious state
to share their key with the healthcare provider. In the latter case, the
healthcare provider reconstructs the FPE key and decrypts the ciphertext.
We assume this decryption happens in an oblivious manner.
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