# US 8,788,426 B2 · Handling medical prescriptions in a secure fashion

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- Number: US 8,788,426 B2
- Document ID: US8788426B2
- Status: Granted
- Kind: B2
- Application number: 13/402,002
- Filed: 2012-02-22
- Published: 2012-06-14
- Granted: 2014-07-22
- Earliest claimed: 2007-12-14
- Assignees: International Business Machines Corporation
- Applicants: Thomas A. Bellwood; Anh Q. Lu
- Inventors: Thomas A. Bellwood; Anh Q. Lu
- Web page: https://patentgrep.com/patent/US8788426B2

## CPC

- H04L 9/0822: {using key encryption key}
- G16H 20/13: delivered from dispensers
- H04L 9/0894: {Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage}
- H04L 2209/601: Broadcast encryption
- H04L 2209/88: Medical equipments
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

Techniques for secure automated dispensing of prescription medications utilize broadcast encryption to encrypt a prescription for storage on a machine-readable medium that is pre-written with a key management block (KMB). The KMB encodes a session key needed to read from or write to the medium. Each prescription-writing device and medication dispensing device is assigned a unique set of device keys, which are used to recover the session key from the medium. Only authorized devices are able to recover the session key from a medium's KMB. Thus, only authorized devices may read or validly write prescriptions from/to the machine-readable medium. In this manner, only authorized providers can write fillable prescriptions and only authorized dispensers can dispense medications to fill those prescriptions.

## Claims

### Claim 1

A method of preparing computer-readable medical prescriptions, comprising:
encrypting, by one or more computers, a prescription for medication with a prescription key;
encrypting, by the computers, the prescription key;
creating, by the computers, an encrypted session key by encrypting session numbers of an unencrypted session key using device keys that are available at one or more authorized receiving devices, wherein the unencrypted session key is derived by logically combining the session numbers;
creating, by the computers, a key management block that includes the encrypted session key, wherein the encrypted session key is decrypted by the one or more authorized receiving devices in order to decrypt the encrypted prescription key;
writing, by the computers, the encrypted prescription key to a machine-readable medium;
writing, by the computers, the encrypted prescription to the machine-readable medium; and
writing, by the computers, the key management block to the machine-readable medium.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
encrypting, by the computers, the prescription key with the unencrypted session key.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
identifying, by the computers, a plurality of devices to be cryptographically revoked that each include a subset of the device keys;
generating, by the computers, a new session key; and
encoding, by the computers, the new session key to form the key management block which cannot be decrypted using any of the subsets possessed by the identified devices.

### Claim 4 (depends on 3)

The method of claim 3, wherein encrypting the prescription and encoding the new session key to form the key management block are performed by different ones of the computers.

### Claim 5

A non-transitory computer-readable medium including stored instructions that, when executed by one or more computers, cause the computers to perform the method of:
encrypting a prescription for medication with a prescription key;
encrypting the prescription key;
creating an encrypted session key by encrypting session numbers of an unencrypted session key using device keys that are available at one or more authorized receiving devices, wherein the unencrypted session key is derived by logically combining the session numbers;
creating a key management block that includes the encrypted session key, wherein the encrypted session key is decrypted by the one or more authorized receiving devices in order to decrypt the encrypted prescription key;
writing the encrypted prescription key to a machine-readable device;
writing the encrypted prescription to the machine-readable device; and
writing the key management block to the machine-readable device.

### Claim 6 (depends on 5)

The non-transitory computer-readable medium of claim 5, wherein the instructions, when executed by the computers, further cause the computers to perform the method of:
encrypting the prescription key with the unencrypted session key.

### Claim 7 (depends on 5)

The non-transitory computer-readable medium of claim 5, wherein the instructions, when executed by the computers, further cause the computers to perform the method of:
identifying a plurality of devices to be cryptographically revoked that each include a subset of the device keys;
generating a new session key; and
encoding the session key to form the key management block which cannot be decrypted using any of the subsets possessed by the identified devices.

### Claim 8 (depends on 7)

The non-transitory computer-readable medium of claim 7, wherein encrypting the prescription and encoding the new session key to form the key management block are performed by different ones of the computers.

### Claim 9

A data processing system, comprising:
one or more computers; and
a computer-readable device including computer-readable instructions embodied on the computer-readable device, wherein the computer-readable instructions, when executed by the computers, cause the computers to perform the method of:
encrypting a prescription for medication with a prescription key;
encrypting the prescription key;
creating an encrypted session key by encrypting session numbers of an unencrypted session key using device keys that are available at one or more authorized receiving devices, wherein the unencrypted session key is derived by logically combining the session numbers;
creating a key management block that includes the encrypted session key, wherein the encrypted session key is decrypted by the one or more authorized receiving devices in order to decrypt the encrypted prescription key;
writing the encrypted prescription key to a machine-readable medium;
writing the encrypted prescription to the machine-readable medium; and
writing the key management block to the machine-readable medium.

### Claim 10 (depends on 9)

The data processing system of claim 9, wherein the computer-readable instructions, when executed by the computers, further cause the computers to perform the method of:
encrypting the prescription key with the session key.

### Claim 11 (depends on 9)

The data processing system of claim 9, wherein the computer-readable instructions, when executed by the computers, further cause the computers to perform the method of:
identifying a plurality of devices to be cryptographically revoked that each include a subset of the device keys;
generating a new session key; and
encoding the new session key to form the key management block which cannot be decrypted using any of the subsets possessed by the identified devices.

### Claim 12 (depends on 11)

The data processing system of claim 11, wherein encrypting the prescription and encoding the new session key to form the key management block are performed by different ones of the computers.

### Claim 13 (depends on 1)

The method of claim 1, wherein the logically combining includes exclusive ORing.

### Claim 14 (depends on 5)

The computer-readable medium of claim 5, wherein the logically combining includes exclusive ORing.

### Claim 15 (depends on 9)

The data processing system of claim 9, wherein the logically combining includes exclusive ORing.