Trusted tokenized transactions in a blockchain system

1. A computer-implemented method for secure tokenized data structures in a blockchain system, the method comprising:

receiving, from a user of an exchange server and over a computer network, a tokenization request for tokenizing a quantity of a security;

generating, by a computer, a digital signature of a fiduciary using a cryptographic private key of the fiduciary, the digital signature derived from identification information of the tokenization request, the identification information comprising an identifier of the security, the digital signature representing that the fiduciary holds the quantity of the security in trust;

recording the digital signature on a first blockchain data structure;

transmitting, over the computer network, published information to a publication source that is separate from the first blockchain data structure, the published information comprising the identification information or information derived from the identification information; and

executing a smart contract on the first blockchain data structure to verify the digital signature, wherein:

verifying the digital signature comprises decrypting the digital signature using a public key of the fiduciary, the public key and the private key forming a public-private key pair, comparing decrypted information in the digital signature to the tokenization request, and comparing the decrypted information in the digital signature to the published information;

the smart contract comprises code instructions that are executable responsive to verification of the digital signature, the code instructions being configured to, when executed, cause the computer to generate a blockchain depository receipt representing the security; and

the blockchain depository receipt is exchangeable by the user through the exchange server.

2. The computer-implemented method of claim 1 , wherein the code instructions, when executed, further cause the computer to broadcast a blockchain transaction for recordation on the first blockchain data structure, the blockchain transaction specifying a transfer of the blockchain depository receipt to a blockchain address of the user in the first blockchain data structure.

3. The computer-implemented method of claim 1 , wherein the identification information of the tokenization request is generated by:

creating a hash of combined information comprising an account identifier of the user, the quantity of the security, the identifier of the security, and a timestamp of the tokenization request, the hash being the identification information.

4. The computer-implemented method of claim 1 , wherein the code instructions of the smart contract define a namespace that is reserved for the exchange server, and the blockchain depository receipt is issued under the namespace, wherein the blockchain depository receipt is tradable only through the exchange server.

5. The computer-implemented method of claim 1 , wherein the blockchain depository receipt is a blockchain token that is tradable through at least a second blockchain data structure separate from the first blockchain data structure.

6. The computer-implemented method of claim 1 , wherein the blockchain depository receipt is divisible into a plurality of portions, each portion being independently tradable by the user to sell the portion to a different user of the exchange server.

7. The computer-implemented method of claim 1 , wherein the blockchain depository receipt is tradable by:

providing, by the exchange server, pricing information of the security in a unit of a blockchain token;

matching, by the exchange server, a sell order of the blockchain depository receipt with a purchase order in a quantity of the blockchain token; and

exchanging, by the exchange server, ownerships of the blockchain depository receipt and the quantity of the blockchain token.

8. The computer-implemented method of claim 1 , wherein the blockchain depository receipt is redeemable by:

receiving the blockchain depository receipt from an owner of the blockchain depository receipt;

transmitting an equivalent quantity of the security to an account of the exchange server, the account belonging to the owner; and

causing the smart contract recorded on the first blockchain data structure to remove the blockchain depository receipt from the first blockchain data structure.

9. A blockchain system for secure tokenized data structures comprising:

an exchange server configured to:

receive a tokenization request for tokenizing a quantity of a security from a user of the exchange server, and

generate a digital signature of a fiduciary, the generation of the digital signature comprising applying a cryptographic private key of the fiduciary to identification information of the tokenization request, the identification information comprising an identifier of the security, the digital signature representing that the fiduciary holds the quantity of the security in trust; and

record the digital signature on a blockchain data structure;

the blockchain data structure comprising a block recording a smart contract, the smart contract comprising code instructions that are executable responsive to verifying the digital signature transmitted from the fiduciary, wherein verifying the digital signature comprises:

decrypting the digital signature using a public key of the fiduciary, the public key and the private key forming a public-private key pair;

comparing decrypted information in the digital signature to the tokenization request; and

comparing the decrypted information in the digital signature to published information retrieved from a publication source that is separate from the blockchain data structure, the published information comprising the identification information or information derived from the identification information; and wherein:

the code instructions, when executed, cause a computer to generate a blockchain depository receipt representing the security, wherein the blockchain depository receipt is exchangeable by the user through the exchange server.

10. The system of claim 9 , wherein the code instructions, when executed, further cause the computer to broadcast a blockchain transaction for recordation on the blockchain data structure, the blockchain transaction specifying a transfer of the blockchain depository receipt to a blockchain address of the user in the blockchain data structure.

11. The system of claim 9 , wherein the identification information of the tokenization request is generated by:

creating a hash of combined information comprising an account identifier of the user, the quantity of the security, the identifier of the security, and a timestamp of the tokenization request, the hash being the identification information.

12. The system of claim 9 , wherein the blockchain data structure restricts transactions of the blockchain depository receipt to accounts of the exchange server.

13. The system of claim 9 , wherein the code instructions of the smart contract define a namespace that is reserved for the exchange server, and the blockchain depository receipt is issued under the namespace, whereby the blockchain depository receipt is tradable only through the exchange server.

14. The system of claim 9 , wherein the blockchain depository receipt is a blockchain token that is tradable through at least a second blockchain data structure separate from the blockchain data structure.

15. The system of claim 9 , wherein the exchange server is further configured to provide pricing information of the security in a unit of a blockchain token.

16. The system of claim 9 , wherein the exchange server is further configured to:

receive a sell order from the user of the exchange server, the sell order specifying the blockchain depository receipt to be sold,

receive a purchase order from another user of the exchange server, the purchase order specifying a quantity of a blockchain token,

match the sell order and the purchase order, and

exchange ownerships of the blockchain depository receipt and the quantity of the blockchain token.

17. A blockchain system for secure tokenized data structures comprising:

an exchange server configured to receive a tokenization request for tokenizing a quantity of a security from a user of the exchange server; and

a fiduciary having an account of the exchange server, the fiduciary configured to:

hold the quantity of the security in trust,

apply a cryptographic private key of the fiduciary to identification information of the tokenization request to generate a digital signature of the fiduciary, the identification information comprising an identifier of the security, the digital signature representing that the fiduciary holds the quantity of the security in trust,

record the digital signature on a blockchain data structure, wherein a smart contract is recorded on the blockchain data structure, the smart contract comprising code instructions that are executable responsive to verifying the digital signature, and transmit published information to a publication source that is separate from the first blockchain data structure, the published information comprising the identification information or information derived from the identification information, wherein verifying the digital signature comprises:

decrypting the digital signature using a public key of the fiduciary, the public key and the private key forming a public-private key pair;

comparing decrypted information in the digital signature to the tokenization request; and

comparing the decrypted information in the digital signature to the published information; and wherein; the code instructions, when executed, cause a computer to generate a blockchain depository receipt representing the security, wherein the blockchain depository receipt is exchangeable by the user through the exchange server.

18. The computer-implemented method of claim 7 , wherein exchanging ownerships of the blockchain depository receipt and the quantity of blockchain token comprises transferring ownership of the blockchain depository receipt to a second user, and the transferring comprises:

debiting a first account of the exchange server for the user with the blockchain depository receipt; and

crediting a second account of the exchange server for the second user with the blockchain depository receipt.

19. The computer-implemented method of claim 7 , wherein exchanging ownerships of the blockchain depository receipt and the quantity of blockchain token comprises transferring the ownership of the blockchain depository receipt to a second user, and the transferring comprises:

broadcasting a blockchain transaction for recordation on the blockchain data structure, the blockchain transaction specifying a transfer of the blockchain depository receipt from a first blockchain address of the user to a second blockchain address of the second user.