IEEE Consumer Electronics Magazine - March/April 2023 - 87

Figure 1 presents the blockchain-based architecture
to generate and maintain medical
certificates, and documents. The proposed
architecture consists of five components: users,
healthcare centers, blockchain network, MA,
and IPFS. Initially, users or healthcare centers
are registered in the blockchain network using
the MA. The healthcare center sends a key generation
request to the MA. The MA sends a
request to the blockchain network and executes
the key generation function to generate public
and private key pairs for the healthcare center.
The blockchain network stores the healthcare
center's details and responds with a public-private
key pair. Then, the MA shares the generated
key pair with the healthcare center. Similarly,
the users are also registered in the blockchain
network and receive public-private key pairs by
submitting necessary details, such as user name
and address. Next, the users may request a medical
certificate from the corresponding registered
healthcare center, if required. The corresponding
healthcare center verifies the details of the
user using the MA. After verification, the certificate
is generated by the healthcare center. Also,
the hash of the generated certificate is mapped
with the combined public keys of the user and
the issuing healthcare center. The public keys of
the healthcare center and the user are combined
using a hash function to generate the combined
key. The combined key, certificate hash, and
transaction hash value are stored on the blockchain
network. Using the generated transaction
hash, the issuing healthcare center can check
the validity of the certificate, as well as the
authenticity of the user. Furthermore, the user
digitally signs the generated certificate using the
private key of the user and stores it on the IPFS
storage system using the MA. The user decrypts
the stored certificate using the public key of the
user and utilizes it for further use. The user may
verify the integrity of the certificate using the
hash values stored on the blockchain network
using the MA. Table 1 shows the details of notations
used in this article.
The proposed blockchain-based application
consists of mainly four smart contract functions,
i.e.; RegisterðÞ, GenerateblockðÞ, Issue CertificateðÞ,
and Verify CertificateðÞ. Algorithm 1 represents
the sequential steps or processes for the
March/April 2023
TABLE 1. Notations with their description.
Notation
User
Healthcarecenter
Uname
Address
Blockchainnetwork
Processrequest
PKh
SKh
PKu
SKu
GenerateðÞ
ShareðÞ
Medicalcertificate
Certificatehash
HashðÞ
CK
MapðÞ
GenerateblockðÞ
TransID
DigitallysignðÞ
StoreðÞ
IPFS()
Storehash
Description
Registered user in the network
Registered healthcare center in the network
Name of the user registered in the network
Address detail of the registered user
Blockchain network
Function to process request send by the MA
Public key of the healthcare center
Private key of the healthcare center
Public key of the user
Private key of the user
Function to generate public-private key pair
Function to share generated details with the
user
Medical certificate generated by the network
Hash of the generated certificate
Function to generate hash
Combined key generated from the public keys of
the user and the healthcare center
Function to map details of a generated certificate
with the healthcare center and user
Function to generate a block of the blockchain
network
Transaction ID
Function to digitally sign the generated
certificate
Function to send a storage request to the MA
Function to store medical certificate on the
decentralized storage system
Stored hash value of the certificate
registration of users in the proposed architecture.
First, the healthcare center sends the registration
request to the MA, i.e., proposed MA with the
details like user name and address. Then, the MA
verifies the user request, if the user is a healthcare
authority/center or an individual end-user. After
the verification, the MA sends a request to the
blockchain network to generate the public and private
key pair. The blockchain network processes
the request and generates the public and private
key pair, and shares it with the user.
87
IEEE Consumer Electronics Magazine - March/April 2023

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