Java Code To Generate Unique Key
- Learn Java Secure Hashing algorithms in-depth. A secure password hash is an encrypted sequence of characters obtained after applying certain algorithms and manipulations on user-provided password, which are generally very weak and easy to guess. There are many such hashing algorithms in Java which can prove really effective for password security.
- Unique Key in SQL. A unique key is a set of one or more than one fields/columns of a table that uniquely identify a record in a database table. You can say that it is little like primary key but it can accept only one null value and it cannot have duplicate values.
Key generators are constructed using one of the getInstance class methods of this class.
KeyGenerator objects are reusable, i.e., after a key has been generated, the same KeyGenerator object can be re-used to generate further keys.
There are two ways to generate a key: in an algorithm-independent manner, and in an algorithm-specific manner. The only difference between the two is the initialization of the object:
- Algorithm-Independent Initialization
All key generators share the concepts of a keysize and a source of randomness. There is an
initmethod in this KeyGenerator class that takes these two universally shared types of arguments. There is also one that takes just akeysizeargument, and uses the SecureRandom implementation of the highest-priority installed provider as the source of randomness (or a system-provided source of randomness if none of the installed providers supply a SecureRandom implementation), and one that takes just a source of randomness.Since no other parameters are specified when you call the above algorithm-independent
initmethods, it is up to the provider what to do about the algorithm-specific parameters (if any) to be associated with each of the keys. - Algorithm-Specific Initialization
For situations where a set of algorithm-specific parameters already exists, there are two
initmethods that have anAlgorithmParameterSpecargument. One also has aSecureRandomargument, while the other uses the SecureRandom implementation of the highest-priority installed provider as the source of randomness (or a system-provided source of randomness if none of the installed providers supply a SecureRandom implementation).
In case the client does not explicitly initialize the KeyGenerator (via a call to an init method), each provider must supply (and document) a default initialization.
Every implementation of the Java platform is required to support the following standard KeyGenerator algorithms with the keysizes in parentheses:
Starting with Java 5, the UUID class provides a simple means for generating unique ids. The identifiers generated by UUID are actually universally unique identifiers. To generate secrete key we can use Java KeyGenerator class which provides the functionality of a secret (symmetric) key generator. Key generators are constructed using one of the getInstance class methods of this class. Generate 16-digit unique code (like product serial). A product serial key. Anyway, I think this code is not satisfied with the third condition (no duplication.
- AES (128)
- DES (56)
- DESede (168)
- HmacSHA1
- HmacSHA256
I have a set of numbers(may be 200- 300 numbers) and i need to generate a 8-10 digit/string key. I need this key to compare another key if that key is also made up of the same set of numbers. Is there a ways to generate a smaller key and also can be compared..
Thx in advance and its urgent
[ July 12, 2005: Message edited by: Mary Cole ]
http://java.sun.com/j2se/1.4.2/docs/api/java/security/MessageDigest.html
http://java.sun.com/developer/technicalArticles/Security/Crypto/
Hashing functions are used to produce a unique key for some input. If the input changes in any way, then the hash produced will be completely different, however if the same input is supplied you will consistently be getting the same hash.
In UNIX, for example, passwords are not stored in cleartext. Instead, the passwords are hashed and the hash is stored. This way if a hacker gets his hands on the hash he/she has no way of getting back the password. This is a property of a one-way hash function - you can only go one way (from password to hash, and not from hash to password). When a user supplies his/her password again to login into the system, the password is hashed once again and compared to what is stored on file. If the hashes match, then you login.
Here I wrote a quick example for you:
[ July 12, 2005: Message edited by: Yevgeniy Treyvus ]
[ July 12, 2005: Message edited by: Yevgeniy Treyvus ]
[ July 12, 2005: Message edited by: Yevgeniy Treyvus ]
Basically what am doing is generating a token based on the user selection of the values in the fields in GUI. 3 scenarios can exist for these selections --
AN user can select multiple products (am storing only productids.which is numeric..and 4-5 digts in length....)
AN user can select multiple vendors(am storing only vendorids.which is numeric. usially 2-3 digits in lenght)
AN user can select both multiple products and vendors( which is again numberic values productid and vendorid)....
So I have an array whcih contains these numbers. I sort this array and build a plain string by looping thru the array.....so the length of the string might be 200+ characters if more selections are made.
Based on this I decide whehter the key already exists in my cache so that I can avoid the trip to DB for doing some calculations.
If another user also selects the same productid, vendorid and productid+vendorid combination i should get the same key so that I can use the cached data without hitting the DB
lets say userA has selected --
productID = 2456
vendorID = 34
productid,vendorid = 2834 , 18
So my token will be 183424562834 (after sorting and looping the array)
If the userB selects the same combination... his token will also be the same
Suppose an userC has following combination--
productID= 1834, 2456,2834 ( he has selected multiple products)
VendorId NONE selected
ProductId,vendorId = NONE selected
Now also the generated toke will be 183424562834.
So my cache result will always be wrong.
Is there any good token generation process so that i can handle all these conditions.
Thx in advance
U
You probably want to have some sort of formatted field where you can specify a key for a vendor without product (i.e. xxxx-34), a product without vendor (i.e. 1234-xx) and a vendor-product combo (i.e. 1234-34).
Its like this... A product can stand on its own...a vendor can stand on its own...but there can be a combination of vendor-produt too...
So for independent product i have the key as '2345-PR'
For independent vendor i have '67-VE'
But for vend and prod combo i have it as '24-6677'
But when I want to build the key ...I will strip off all the characters so that I have plain numbers.
Hope am clear on this
Originally posted by Mary Cole:
I will strip off all the characters so that I have plain numbers.
I think that's your problem. You need some context to your key so you aren't confusing product 1234 with vendor 12 and vendor 34.
productID= 1834, 2456,2834 ( he has selected multiple products)
VendorId NONE selected
ProductId,vendorId = NONE selected
to be 3 seperate queries, one for each product.
posted 14 years agoJava Create Unique Id
posted 14 years agoStill confused. I don't see any connection between the requirements you've specified so far and the need for a 10-digit key. Even if you wanted to take an entire query like this:
productID= 1834, 2456,2834 ( he has selected multiple products)
VendorId NONE selected
ProductId,vendorId = NONE selected
and shrink it down to 10 digits, you are losing information. You will have name collision, where two queries that are not equal will resolve to the same name and dropouts, where two queries that should be equal do not resolve to the same name.
If it were me, I'd cache each product id seperately, otherwise your cache will duplicate information (i.e. if you had another query productID= 1834, 2456, you don't want to store the results AGAIN, because they duplicate 2/3 of the previous query).