Chain of authentication using public key infrastructure

1. A method comprising:

generating, by a user, a first private key and a first public key corresponding to each other;

generating, by a service provider, a second private key and a second public key corresponding to each other;

transmitting, from the user to the service provider, the first public key signed with the first private key;

verifying, by the service provider, the received first public key signed with the first private key;

in response to successfully verifying the received first public key signed with the first private key, generating, by the service provider, a level 2 key by concatenating the first public key signed with the first private key and the second public key signed with the second private key; and

transmitting, by the service provider, the level 2 key to the user,

wherein a level of the key is visually displayed on a virtual representation of the user in a virtual environment or a metaverse.

2. A method comprising:

generating, by a user, a first private key and a first public key corresponding to each other;

generating, by an n th service provider, an n th private key and an n th public key corresponding to each other;

transmitting, from the user to the n th service provider, a level n key;

generating, by the n th service provider, a level (n+1) key by concatenating the level n key and the n th public key signed with the n th private key; and

transmitting, by the n th service provider, the level (n+1) key to the user,

wherein n is a natural number,

wherein when n=1, the level 1 key is the first public key signed with the first private key, and

wherein a level of the key is visually displayed on a virtual representation of the user in a virtual environment or a metaverse.

3. The method of claim 2 , further comprising:

verifying, by the n th service provider, the level n key.

4. The method claim 2 , wherein the level of the key is displayed by a number of rings over the virtual representation of the user, colors of rings over the virtual representation of the user, colors of rosary on the virtual representation of the user, a number of stones on a gauntlet or a glove worn by the virtual representation of the user, a color of glasses worn by the virtual representation of the user, a length of a wand or a baton or a light sword that the virtual representation of the user possesses, or any combination thereof.

5. The method of claim 2 , wherein the first private key and the first public key are generated based on a first public key certificate in which a first code is inserted, and

wherein the first code includes information associated with biometric data or a combination of pieces of biometric data, information associated with unique identity information, information associated with an Internet of Things device, information associated with a QR code, information associated with an identity information, information associated with electronic money, information associated with a cryptographic hash function address, information associated with a crypto currency, information associated with digital cash, information associated with central bank digital currency (CBDC), information associated with blockchain, information associated with a decentralized identifier (DID), information associated with metaverse, information associated with virtual property on metaverse, or any combination thereof.

6. The method of claim 2 , further comprising:

resetting, by the user, the level n key to the level 1 key.

7. The method of claim 2 , further comprising:

restoring, by the user, the level (n+1) key to the level n key.

8. The method of claim 7 , further comprising:

recovering, by the user, from the level n key to the level (n+1) key.

9. The method of claim 2 , further comprising:

decreasing, by the user, a level of the key; and

transferring, by the user, rights of the key to another user.