Jun 23, 2017 1. You can use surrogate IDs when updating objects, but the IDs may not be readily available to Oracle HCM Cloud users. Default source keys are generated only if you don't supply a source key when creating an object. You can't use user keys alone when updating some objects because their values are subject to change. Using User-Generated KMS Master Keys. After the correct permissions are applied to your consumers, producers, and administrators, you can use custom KMS master keys in your own AWS account or another AWS account.
A key serves as a unique identifier for each entity instance. Most entities in EF have a single key, which maps to the concept of a primary key in relational databases (for entities without keys, see Keyless entities). Entities can have additional keys beyond the primary key (see Alternate Keys for more information).
By convention, a property named
Id or <type name>Id will be configured as the primary key of an entity.
Note
Owned entity types use different rules to define keys.
You can configure a single property to be the primary key of an entity as follows:
You can also configure multiple properties to be the key of an entity - this is known as a composite key. Composite keys can only be configured using the Fluent API; conventions will never setup a composite key, and you can not use Data Annotations to configure one.
Primary key name
By convention, on relational databases primary keys are created with the name
PK_<type name> . You can configure the name of the primary key constraint as follows:
Key types and values
While EF Core supports using properties of any primitive type as the primary key, including
string , Guid , byte[] and others, not all databases support all types as keys. In some cases the key values can be converted to a supported type automatically, otherwise the conversion should be specified manually.
Key properties must always have a non-default value when adding a new entity to the context, but some types will be generated by the database. In that case EF will try to generate a temporary value when the entity is added for tracking purposes. After SaveChanges is called the temporary value will be replaced by the value generated by the database.
Important
If a key property has its value generated by the database and a non-default value is specified when an entity is added, then EF will assume that the entity already exists in the database and will try to update it instead of inserting a new one. To avoid this turn off value generation or see how to specify explicit values for generated properties.
Alternate Keys
An alternate key serves as an alternate unique identifier for each entity instance in addition to the primary key; it can be used as the target of a relationship. When using a relational database this maps to the concept of a unique index/constraint on the alternate key column(s) and one or more foreign key constraints that reference the column(s).
Tip
Which Keys Are Generated When You Use One
If you just want to enforce uniqueness on a column, define a unique index rather than an alternate key (see Indexes). In EF, alternate keys are read-only and provide additional semantics over unique indexes because they can be used as the target of a foreign key.
Alternate keys are typically introduced for you when needed and you do not need to manually configure them. By convention, an alternate key is introduced for you when you identify a property which isn't the primary key as the target of a relationship.
You can also configure a single property to be an alternate key:
You can also configure multiple properties to be an alternate key (known as a composite alternate key):
Finally, by convention, the index and constraint that are introduced for an alternate key will be named
AK_<type name>_<property name> (for composite alternate keys <property name> becomes an underscore separated list of property names). You can configure the name of the alternate key's index and unique constraint:
Updated on March 30, 2020
Spend enough time in an IT environment and you will likely come across the term SSH keys. If you’ve already come across this IT term, then you might find yourself wondering, what are SSH keys? SSH (Secure Shell) keys are an access credential that is used in the SSH protocol.
Which Keys Are Generated When You Use Us
Read the rest of this post to learn more about what are SSH keys or consider watching webinar below to find out more about the SSH protocol and the basics of SSH authentication.
Before this post delves into an explanation on what are SSH keys, let’s take a quick look at the SSH protocol.
The SSH Protocol
The first version of the SSH protocol was developed in the summer of 1995 by Tatu Ylonen. Tatu was a researcher at the University of Helsinki when a sniffing attack was discovered on the university network. A sniffing attack intercepts and logs the traffic that takes place on a network, and can provide attackers with usernames and passwords which can then be used to gain access to critical IT assets. Thousands of credentials were impacted, including those belonging to community partnerships. This sniffing attack motivated Tatu to figure out how to make networks more secure, and this ultimately led to the creation of the SSH protocol (SSH.com).
Today, the SSH protocol is widely used to login remotely from one system into another, and its strong encryption makes it ideal to carry out tasks such as issuing remote commands and remotely managing network infrastructure and other vital system components. To use the SSH protocol, a couple pieces of software need to be installed. The remote systems need to have a piece of software called an SSH daemon, and the system used to issue commands and manage the remote servers needs to have a piece of software called the SSH client. These pieces of software are necessary to create a proper communication channel using the SSH protocol (DigitalOcean).
Essentially, SSH keys are an authentication method used to gain access to this encrypted connection between systems.
What are SSH keys?Which Keys Are Generated When You Use Iphone
SSH keys come in many sizes, but a popular choice is RSA 2048-bit encryption, which is comparative to a 617 digit long password. On Windows systems, it is possible to generate your own SSH key pair by downloading and using an SSH client like PuTTY. On Mac® and Linux® systems, it is possible to generate an SSH key pair using a terminal window. Watch the video below to find out how to generate your own RSA key pair on Mac and Linux.
SSH keys always come in pairs, and each pair is made up of a private key and a public key. Who or what possesses these keys determines the type of SSH key pair. If the private key and the public key remain with the user, this set of SSH keys is referred to as user keys. If the private and public key are on a remote system, then this key pair is referred to as host keys. Another type of SSH key is a session key. When a large amount of data is being transmitted, session keys are used to encrypt this information.
Now let’s take a closer look at how a private key and public key work. To keep things simple, we will focus on how user keys work.
How User Keys Work
In a user key set, the private key remains on the system being used to access the remote system and is used to decrypt information that is exchanged in the SSH protocol. Private keys should never be shared with anyone. A public key is used to encrypt information, can be shared, and is used by the user and the remote server. On the server end, the public key is saved in a file that contains a list of authorized public keys. On the user’s side, the public SSH key is stored in an SSH key management software or in a file on their computer.
Using SSH KeysFirst Steps
Before you can start using SSH keys, first you need to generate your own SSH key pair on the system you would like to use to access a remote system. This article and the video mentioned above are great resources that can guide you through on how to generate an SSH key pair. Once the key pair is generated, the next step is to put the public SSH key on the remote server. Depending on your setup, this can be done by entering a couple commands in the terminal window, using JumpCloud, or by manually placing the public SSH key on the remote server (DigitalOcean).
Behind the Scenes of SSH Key Authentication
After completing the steps mentioned above, use your terminal to enter in your ssh username and the IP address of the remote system in this format: ssh username@my_ip_address. This will initiate a connection to the remote system using the SSH protocol. The protocol and specified username will then tell the remote server which public key to use to authenticate you. Then the remote server will use that public key to encrypt a random challenge message that is sent back to the client. This challenge message is decrypted using the private key on your system. Once the message is decrypted, it is combined with a previously arranged session ID and then sent back to the server. If the message matches with what the server sent out, the client is authenticated, and you will gain access to the remote server. This process proves to the server that you have the corresponding private key to the public key it has on file.
However, the security that this authentication process provides can be undermined when SSH keys are not properly managed.
Managing SSH KeysWhich Keys Are Generated When You Use Us
It is imperative that proper SSH key management is in place because they often grant access to mission-critical digital assets. Also, companies tend to have a lot of SSH keys. In fact, Fortune 500 companies will often have several millions of these. Despite the difficulty in trying to manually manage millions of SSH keys, having an SSH key management system in place is continuously overlooked. SSH.com did some digging and discovered a company that had 3 million SSH keys “that granted access to live production servers. Of those, 90% were no longer used. Root access was granted by 10% of the keys, ” (SSH.com). An effective SSH key management system in place would have gone a long way in reducing this concerning security risk.
IT has a couple options to gain control over SSH keys in their environment. One of these includes using an SSH key management tool. However, this means having to manage one more platform in addition to managing an SSO provider, a directory service, and maybe a system management solution. A new solution has emerged that is providing IT with a second option: Directory-as-a-Service®.
Cloud IAM offers SSH Key Management
This cloud-based identity and access management (IAM) solution provides IT with one central place to manage SSH keys. Furthermore, IT can also centralize user authentication to Mac, Linux, and Windows systems, cloud servers, wired and WiFi networks, web-based and on-prem applications, and virtual and on-prem storage. With one central place to manage a user’s authentication to all of their resources, it becomes a simple matter of a few clicks to deprovision users from all of their resources, including SSH key access to remote systems.
Learn More about SSH Key Management with JumpCloud
For more information, consider reading this support article on how JumpCloud assists with SSH key management, or exploring this guide for a modern approach to managing user accounts on your cloud servers.
You are also more than welcome to reach out to us if you would like more information on how DaaS can simplify your SSH key management. If you’re ready to start testing our modern IAM platform, sign up for a free account. You’ll be able to explore all of our features, and your first ten users are free forever. Comments are closed.
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December 2020
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