1. Use A Uuid To Generate Encryption Keys
2. Use A Uuid To Generate Encryption Key In Excel

Best practice is to use a PBKDF to generate a 'key encryption key' (KEK), then a full entropy random key is used to encrypt the data, and the KEK is used to encrypt that key. That way a password change does not require reencryption of all the data, just the key. The KEK is never stored, only used to encrypt and decrypt the data key.

• Jul 17, 2018 A key pair is generated, and a file named FileVaultMaster.keychain is saved to your desktop. Copy this file to a secure location, such an encrypted disk image on an external drive. This secure copy is the private recovery key that can unlock the startup disk of any Mac set up to use the FileVault master keychain. It is not for distribution.
• The GUID keys can be predicted, at least those generated by.NET / WinAPI. Also keep in mind that the GUID does not even have a true 128bit randomness, because the version number is fixed. This gives you a very weak key in the first place. To make matters worse, several versions of the GUID algorithm suffer from predictability.
• Encryption Key Generator. The all-in-one ultimate online toolbox that generates all kind of keys! Every coder needs All Keys Generator in its favorites! It is provided.
• Feb 12, 2017  There are several reasons using a UUID as a PK would be great compared to auto-incrementing integers: At scale, when you have multiple databases containing a segment (shard) of your data, for example a set of customers, using a UUID means that one ID is unique across all databases, not just the one you’re in now.
• Apr 23, 2019 Note also that most databases WILL create a unique id as the primary key for every record in a table–though the value is only unique to that table. Some can be told to create a uuid for that primary key, for what that’s worth. Then if you are going to pass such an id on a URL, you should use the urlencodedformat function around that.
• As for the AES key, I am hashing the company GUID the database record belongs to using SHA256 (resulting in the same key on each server that is trying to decrypt the record from the DB) I am unable to use SQL encryption for various reasons and must use code for encryption/decryption.

You use the PSCipherJava utility's buildkey command to build new Triple DES encryption keys.The buildkey command adds a new Triple DES encryption key stored in the psvaultfile (the key file). If you generate new versions of the key file,the system appends the new version of the key to the end of the keyfile.

To invoke the commandon a Windows server, change to the directory where PSCipher residesand enter:

To invoke the commandon UNIX, change to the directory where PSCipher resides and enter:

Select one web serverin your system to generate the new version of the key file. The pscipher.batand PSCipher.sh utilities only run in the Java environment of theweb server. After you have created the new key file, you then copythe new version of psvault from the initial server to the appropriatedirectories on all the appropriate servers in your system. The psvaultfile is stored in different directories depending on your web servervender (as described in the following sections). On the applicationserver the psvault file resides in <PS_HOME>secvault.

Note: If you are not usingthe default encryption key and you have generated a unique encryptionkey, note that each time you add a new server to your system, youwill need to copy the key file to the appropriate location on thatserver. For example, if you are using the default key version ({V1.1}),any server you add to the system and install PeopleTools on will alsohave the default key version ({V1.1}). As such, no further steps arerequired. However, if you have generated a new key, giving the versionnumber a value of {V1.2} or greater, then you need to make sure tocopy that key file to the added server(s). Also, each time you updatethe key, you need to ensure that the new version of the key file iscopied to the additional servers in your system.

Warning! When you upgrade tonew PeopleTools releases, as in PeopleTools 8.48 to PeopleTools 8.50,you will need to backup any modifications you have made to the keyfile using PSCipher in the previous release and reapply that samekey file to the appropriate servers onto which you have installedthe new PeopleTools release.

The architectural consequences of using UUID/GUID's may outweigh their benefits.

For the purpose of this post, I will use UUID (Universally Unique Identifier) to mean both UUID and GUID (Globally Unique Identifier, Microsoft's implementation of UUID).

I've been thinking a lot about UUID's lately. The system I've inherited at work is plagued by their usage. To many developers, the UUID seems like a totally awesome way to establish the identity of a record in a system. I mean, how cool is it that you can generate an ID unique to every system in the world?.

The purpose of this post is to discuss appropriate and inappropriate uses of UUIDs. My goal is to encourage engineers to think about the general consequences of data type selection for identifiers in their architectures.

To most databases, UUID's are just 36 character strings.

Databases like MySQL do not have a native implementation of the data structure. This means the column that carries the value must at least be 36 characters (VARCHAR(36)). When you consider the text encoding (e.g. MySQL character set) used to represent strings, this could mean 2-3 bytes per character (if using UTF-8). That means at least 72 bytes per identifier!

While this doesn't seem like a big deal, consider that for every 13,889 identifiers, your database will consume 1MB of storage. If you are using Foreign Keys, and they are also UUID's, that's another 1MB of storage for each Foreign Key.

UUIDs degrade database performance.

If you use a UUID as an identifier for a table, you're going to have to index it. Unfortunately, UUID's don't index well. The problem is their size and randomness. Indexes are trees that grow and branch as you add more data. Sequential values tend to index well because they don't require large sections of the index to be realigned (e.g. splitting a value into a new branch of values - refer to B-tree). UUID's are designed to be non-sequential and they are very large compared to an integer. This means the more UUIDs you insert, the larger the insertion penalty will be.

Don't take my word for it, just look at the statistics: http://kccoder.com/mysql/uuid-vs-int-insert-performance/. Notice the nearly consistent insertion time of a long integer vs. the UUID. More importantly, note that the scale on the left is 'insert time in hours'.

You will very certainly see better performance on queries using integers as well, though this might not be as pronounced. Auto incremented integers will almost always be smaller, meaning scans against tables/records will be more efficient. On the other hand, the index that stores UUID identifiers will grow much larger and at a faster rate than integers. This means a UUID index will become disk bound (because it can't fit completely into memory) more quickly than an integer index.

Are UUID's the right data structure for the task?

The point of a UUID is to have a universally unique identifier. There's generally two reason to use UUIDs:

1. You do not want a database (or some other authority) to centrally control the identity of records.
2. There's a chance that multiple components may independently generate a non-unique identifier.

These concerns should generally only arise when you are in a concurrent or distributed environment. The first reason is about avoiding an unnecessary call to an external system. You don't want a high-throughput message broker like RabbitMQ asking MySQL for an identifier every time it publishes a message. The second is generally a concern of a distributed system that requires a high write throughput and uses the key (generally a UUID) to determine the instance/server/partition it needs to write to.

Generate gpg key for local redhat repo 10. The question is, does your system actually have the same requirements?

The following are use cases in which I'd argue you don't need a UUID.

1. Application writes records to a single database (or a cluster in master/slave configuration).

If there is only one database accepting writes, you don't have a need to route records using a unique key.

If portions of the data structure are going to update more than one table (and you need the ID before inserting records into those other tables in one single transaction), you could encapsulate the mutations in a stored procedure. I will admit that this may not be true in a NoSQL database with limited macro/remote execution functionality. In that case it may make sense to generate the ID outside of the database an perform simultaneous mutations. If you do this you are probably not doing it within a transaction and will need to account for inconsistency in your data stores if the operation fails mid-update.

2. There's a Natural Key for your record.

A natural key is a property or group of properties that make your record unique. A phone number or social security number could serve as a unique identifier. In a distributed system, this could be the combination of server IP, application, and timestamp. The point is, there may not be a need to have a UUID to establish record identity in a database.

Use A Uuid To Generate Encryption Keys

If you need to distribute writes across servers, you could simply hash the natural key (concatenating fields if it's a composite) for a unique identifier. If the hashing strategy is well know amongst components in the architecture, you will not need to store the hash (since components will know how to regenerate it on the fly when performing lookups).

Use A Uuid To Generate Encryption Key In Excel

3. When you need to present an ID to a user.

Consider an HR application for a small company (30 employees). Does a UUID make sense for an employee ID? Could you imagine if your employee number was: 2a6db8e1-8967-4511-9839-a7cb3a895710? Of course not! We're accustomed to a more friendly number we can remember.

There's an argument for this same kind of recognizability in the URI's we present users and application developers:

I can probably readily remember the second URL if that user identifier was mine. The first one? Forget it!

Conclusion

UUID's should be a last resort tactic,employed only after you have exhausted other strategies for determining uniqueness in an architecture. In a database, they are generally considered an anti-pattern and should be avoided due to the performance limitations in indexing their values. UUID's also not particularly friendly to users. Instead, engineers should use natural keys as much as possible, and auto incremented integers as an alternative (when it makes sense).

Stumbling my way through the great wastelands of enterprise software development.