Patent AU-2020202482-A1 (AU)
Title: A computer system implemented method for generating a symmetric encryption key for encrypting and decrypting secure data
Inventor: ANSON MARK RODNEY
IPC: G06F21/00
Filed: 2020-04-09
Abstract: Aspects of invention include: methods and apparatus implemented in a 
5 computer system, the methods and apparatus producing a symmetric encryption 
key termed a Cipherkey produced for protecting a computer system user's 
hidden data from unauthorised access by an intruder. The methods and 
apparatus receive a first input item being a user supplied secret termed the 
Secret, and a second input item termed Encrypted Random Data which is a 
0 sufficiently large mass of encrypted data bytes. The Secret can be a password 
comprised of alphanumeric text, a geometric shape input, biometric data, or 
more generally any item of unchanging information only known by or more 
generally insertable only by the valid user of a computer system. The second 
input item Encrypted Random Data shall be the encrypted transformation of a 
5 sufficiently large block of pseudo-random text, a big block of encrypted data 
stored and preserved in computer storage. After receiving a first input item, a 
Secret, a computer system performs a precise method of computation based on 
this input. In a first step the Secret is hashed in three different ways using three 
different one-way cryptographic hashing algorithms such as SHA-256, SHA
20 384 and SHA-512 so as to compute three different hash values identified by the 
terms Hash1, Hash2 and Hash3. In a second step, one of those three different 
hash values, Hash2, is transformed into a string of text that can be used as a file 
name identifier or signifier. In the third step, a computer system takes the file 
name identifier and searches a computer storage to find data with the 
25 corresponding file name. If corresponding data is found, a computer system will 
read the stored data corresponding to the file name and store this input in the 
memory of a computer system. This data found in storage in the third step is the
second input item, the Encrypted Random Data. In a fourth step, the Encrypted 
Random Data is decrypted using the third hash value as a decryption key, the 
Hash3 value. The decrypted result of the fourth step is termed a Random Data 
object. In the fifth step, a computer system joins the bytes of data of the Hash1 
5 value and the decrypted Random Data bytes into a single item of data called a 
Cipherkey source material. In the sixth step, this Cipherkey source material is 
hashed with a one-way cryptographic hashing algorithm to output a hash value 
result termed a Cipherkey, a hash value that can be used a symmetric encryption 
key for protecting a computer system user's hidden data.  
0
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START 101 
OBTAIN USERS SECRET PASSWORD 103 
APPLY AT LEAST ONE HASHING ALGORITHM TO HASH THE USERS 
SECRET PASSWORD AT LEAST ONE TIME CREATING AT LEAST 105 
A FIRST HASH VALUE TERMED THE HASH1 
PRODUCE A RANDOM DATA 107 
ENCRYPTED AND DECRYPTED 
WITH HASHl 
PRODUCE CIPHERKEY SOURCE MATERIAL 109 
CIPHERKEY SOURCE MATERIAL 111 
HASHi VALUE DERIVED 
FROM USER'S PASSWORD 113 RANDOM DATA 115 
APPLY HASHING ALGORITHM TO THE CIPHERKEY SOURCE MATERIAL 117 
CREATING A SYMMETRIC KEY TERMED THE CIPHERKEY 
CIPHERKEY 119 
USE CIPHERKEY TO DECRYPT A CONFIGURATION DATA FOR THE USER 
+ 121 
USER CONFIGURATION DATA 123 
PROVIDE CRYPTOGRAPHIC FUNCTIONS TO THE USER 125 
FIG. 1