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13.12.2020

Sql Server 2014 Generate Hash Key

Sql Server Hash Column
Sql Server 2014 Generate Hash Key In Windows 10
Sql Server 2014 Generate Hash Key In Excel

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Feb 01, 2017 In SQL Server, for simple hash code encryption like password encryption, we can use the HASHBYTES function to encrypt the string.This is a built-in cryptographic function with hashing algorithms like MD-2, MD-4, MD-5, SHA-1, SHA-2 (256 and 512). I have this table which doesn't have a primary key. I'm going to insert some records in a new table to analyze them and I'm thinking in creating a new primary key with the values from all the available columns. If this were a programming language like Java I would: int hash = column1. 31 + column2. 31 + column3.31 Or something like that.

APPLIES TO: SQL Server Azure SQL Database Azure Synapse Analytics (SQL DW) Parallel Data Warehouse

Feb 01, 2017 In SQL Server, for simple hash code encryption like password encryption, we can use the HASHBYTES function to encrypt the string.This is a built-in cryptographic function with hashing algorithms like MD-2, MD-4, MD-5, SHA-1, SHA-2 (256 and 512).
A search based on an integer column can be dramatically faster than a search based on a lengthy string key, and more so if it is a compound key. Hash Key Algorithms using the Checksum Function. There are several algorithms available, the simplest of which is built into SQL Server in the form of the Checksum function.
Jan 14, 2014 SQL Server 2014 Learning Series. A-Z of In-Memory OLTP: Hash Indexes (Part 2). I have given bucket count as 200. Can you guess how much bucket SQL Sever is going to create? If you can’t answer then you have not read part 1 of hash indexes, which I mentioned in beginning. SQL is going to put 256 buckets for both indexes.

Generates a symmetric key and specifies its properties in SQL Server.

This feature is incompatible with database export using Data Tier Application Framework (DACFx). You must drop all symmetric keys before exporting.

Syntax

Arguments

Key_name
Specifies the unique name by which the symmetric key is known in the database. Temporary keys are designated when the key_name begins with one number (#) sign. For example, #temporaryKey900007. You cannot create a symmetric key that has a name that starts with more than one #. You cannot create a temporary symmetric key using an EKM provider.

AUTHORIZATION owner_name
Specifies the name of the database user or application role that will own this key.

FROM PROVIDER provider_name
Specifies an Extensible Key Management (EKM) provider and name. The key is not exported from the EKM device. The provider must be defined first using the CREATE PROVIDER statement. For more information about creating external key providers, see Extensible Key Management (EKM).

Note

This option is not available in a contained database.

KEY_SOURCE ='pass_phrase'
Specifies a pass phrase from which to derive the key.

IDENTITY_VALUE ='identity_phrase'
Specifies an identity phrase from which to generate a GUID for tagging data that is encrypted with a temporary key.

PROVIDER_KEY_NAME**='key_name_in_provider'**
Specifies the name referenced in the Extensible Key Management provider.

Note

This option is not available in a contained database.

CREATION_DISPOSITION = CREATE_NEW
Creates a new key on the Extensible Key Management device. If a key already exists on the device, the statement fails with error.

CREATION_DISPOSITION = OPEN_EXISTING
Maps a SQL Server symmetric key to an existing Extensible Key Management key. If CREATION_DISPOSITION = OPEN_EXISTING is not provided, this defaults to CREATE_NEW.

certificate_name
Specifies the name of the certificate that will be used to encrypt the symmetric key. The certificate must already exist in the database.

'password'
Specifies a password from which to derive a TRIPLE_DES key with which to secure the symmetric key. password must meet the Windows password policy requirements of the computer that is running the instance of SQL Server. Always use strong passwords.

Sql Server Hash Column

symmetric_key_name
Specifies a symmetric key, used to encrypt the key that is being created. The specified key must already exist in the database, and the key must be open.

asym_key_name
Specifies an asymmetric key, used to encrypt the key that is being created. This asymmetric key must already exist in the database.

<algorithm>
Specify the encrypting algorithm.

Warning

Beginning with SQL Server 2016 (13.x), all algorithms other than AES_128, AES_192, and AES_256 are deprecated. To use older algorithms (not recommended), you must set the database to database compatibility level 120 or lower.

Remarks

When a symmetric key is created, the symmetric key must be encrypted by using at least one of the following: certificate, password, symmetric key, asymmetric key, or PROVIDER. The key can have more than one encryption of each type. In other words, a single symmetric key can be encrypted by using multiple certificates, passwords, symmetric keys, and asymmetric keys at the same time.

Caution

When a symmetric key is encrypted with a password instead of a certificate (or another key), the TRIPLE DES encryption algorithm is used to encrypt the password. Because of this, keys that are created with a strong encryption algorithm, such as AES, are themselves secured by a weaker algorithm.

The optional password can be used to encrypt the symmetric key before distributing the key to multiple users.

Temporary keys are owned by the user that creates them. Temporary keys are only valid for the current session.

IDENTITY_VALUE generates a GUID with which to tag data that is encrypted with the new symmetric key. This tagging can be used to match keys to encrypted data. The GUID generated by a specific phrase is always the same. After a phrase has been used to generate a GUID, the phrase cannot be reused as long as there is at least one session that is actively using the phrase. IDENTITY_VALUE is an optional clause; however, we recommend using it when you are storing data encrypted with a temporary key.

There is no default encryption algorithm.

Important

We do not recommend using the RC4 and RC4_128 stream ciphers to protect sensitive data. SQL Server does not further encode the encryption performed with such keys.

Information about symmetric keys is visible in the sys.symmetric_keys catalog view.

Symmetric keys cannot be encrypted by symmetric keys created from the encryption provider.

Clarification regarding DES algorithms:

DESX was incorrectly named. Symmetric keys created with ALGORITHM = DESX actually use the TRIPLE DES cipher with a 192-bit key. The DESX algorithm is not provided. This feature is in maintenance mode and may be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.
Symmetric keys created with ALGORITHM = TRIPLE_DES_3KEY use TRIPLE DES with a 192-bit key.
Symmetric keys created with ALGORITHM = TRIPLE_DES use TRIPLE DES with a 128-bit key.

Sql Server 2014 Generate Hash Key In Windows 10

Deprecation of the RC4 algorithm:

Repeated use of the same RC4 or RC4_128 KEY_GUID on different blocks of data, results in the same RC4 key because SQL Server does not provide a salt automatically. Using the same RC4 key repeatedly is a well known error that will result in very weak encryption. Therefore we have deprecated the RC4 and RC4_128 keywords. This feature will be removed in a future version of Microsoft SQL Server. Do not use this feature in new development work, and modify applications that currently use this feature as soon as possible.

Warning

The RC4 algorithm is only supported for backward compatibility. New material can only be encrypted using RC4 or RC4_128 when the database is in compatibility level 90 or 100. (Not recommended.) Use a newer algorithm such as one of the AES algorithms instead. In SQL Server 2019 (15.x) material encrypted using RC4 or RC4_128 can be decrypted in any compatibility level.

Permissions

Requires ALTER ANY SYMMETRIC KEY permission on the database. If AUTHORIZATION is specified, requires IMPERSONATE permission on the database user or ALTER permission on the application role. If encryption is by certificate or asymmetric key, requires VIEW DEFINITION permission on the certificate or asymmetric key. Only Windows logins, SQL Server logins, and application roles can own symmetric keys. Groups and roles cannot own symmetric keys.

Examples

A. Creating a symmetric key

Sql Server 2014 Generate Hash Key In Excel

The following example creates a symmetric key called JanainaKey09 by using the AES 256 algorithm, and then encrypts the new key with certificate Shipping04.

B. Creating a temporary symmetric key

The following example creates a temporary symmetric key called #MarketingXXV from the pass phrase: The square of the hypotenuse is equal to the sum of the squares of the sides. The key is provisioned with a GUID that is generated from the string Pythagoras and encrypted with certificate Marketing25.

C. Creating a symmetric key using an Extensible Key Management (EKM) device

The following example creates a symmetric key called MySymKey by using a provider called MyEKMProvider and a key name of KeyForSensitiveData. It assigns authorization to User1 and assumes that the system administrator has already registered the provider called MyEKMProvider in SQL Server.

A hash index consists of a collection of buckets organized in an array. A hash function maps index keys to corresponding buckets in the hash index. The following figure shows three index keys that are mapped to three different buckets in the hash index. For illustration purposes the hash function name is f(x).

The hashing function used for hash indexes has the following characteristics:

SQL Server has one hash function that is used for all hash indexes.
The hash function is deterministic. The same index key is always mapped to the same bucket in the hash index.
Multiple index keys may be mapped to the same hash bucket.
The hash function is balanced, meaning that the distribution of index key values over hash buckets typically follows a Poisson distribution.
Poisson distribution is not an even distribution. Index key values are not evenly distributed in the hash buckets. For example, a Poisson distribution of n distinct index keys over n hash buckets results in approximately one third empty buckets, one third of the buckets containing one index key, and the other third containing two index keys. A small number of buckets will contain more than two keys.

If two index keys are mapped to the same hash bucket, there is a hash collision. A large number of hash collisions can have a performance impact on read operations.

The in-memory hash index structure consists of an array of memory pointers. Each bucket maps to an offset in this array. Each bucket in the array points to the first row in that hash bucket. Each row in the bucket points to the next row, thus resulting in a chain of rows for each hash bucket, as illustrated in the following figure.

The figure has three buckets with rows. The second bucket from the top contains the three red rows. The fourth bucket contains the single blue row. The bottom bucket contains the two green rows. These could be different versions of the same row.

For more information about indexes for memory-optimized tables, see Guidelines for Using Indexes on Memory-Optimized Tables.