C Generate Random Symmetric Key
The following code samples illustrate how to use cryptography in C# and VisualBasic.NET for such common tasks as data encryption, hashing, and random password generation.
Illustrates how to generate a persistent (i.e. non-random) symmetric key and use this key to encrypt and decrypt data. This sample is intended to help novice users get a grasp on encryption and decryption.
A new random symmetric key generator: AASN algorithm. A Secret key to generate randomness in the r esult). 4 CONCLUSIONS AND DISCUSSIONS. The Secret Key entered by the user is pr e-decided. Symmetric keys don't need to be in any particular format - they're just a sequence of (pseudo)random bits. Most programming environments provide some sort of 'secure random' mechanism (a CSPRNG).You can use this to acquire a byte array of the appropriate length (e.g. 32 bytes for AES256), which can be used as a key. There is one common approach which is usually followed to generate a random secret key for a symmetric cipher and then encrypt this key via asymmetric key cryptography. Due to this pattern, the original message itself is encrypted using the symmetric cipher and then using secret key. The receiver after receiving the message decrypts the message. Ways to generate symmetric and asymmetric keys. Ask Question. Symmetric for encryption big firmware file and asymmetric for encrypting symmetric key file., urandom suggest to use urandom in case one is not sure about it. However we have seed enough. Demo of Symmetric Key Encryption using OpenSSL. The following is an example of using OpenSSL in Ubuntu Linux to perform symmetric key encryption. DES with ECB mode of operation is used. I have a similar demo of OpenSSL for DES encryption as a screencast. When used as a replacement for Sec Key Generate, set the k Sec Use Keychain key to the keychain (Sec Keychain) into which the key should be stored, k Sec Attr Label to a user-visible label for the key, and k Sec Attr Application Label to an identifier defined by your application, for subsequent use in calls to Sec Item Copy Matching(: :).
Explains how to use random salt values when encrypting the same plain text value with the same symmetric key to generate different cipher text. This approach eliminates the need to use different initialization vectors or keys for the purpose of avoiding dictionary attacks.
Demonstrates how to encrypt and decrypt data using Windows Data Protection API (DPAPI).
Illustrates how to hash a text string with a random salt value using various hashing algorithms and verify a hash against a plain text value.
Shows how to generate a random password, which consists of a combination of 7-bit ASCII alpha-numeric characters and special symbols, but does not contain ambiguous characters (such as [1,I,l]).
-->C Generate Random Symmetric Keyboard
Symmetric Algorithms
Returns one row for every symmetric key created with the CREATE SYMMETRIC KEY statement.
| Column name | Data type | Description |
|---|---|---|
| name | sysname | Name of the key. Unique within the database. |
| principal_id | int | ID of the database principal who owns the key. |
| symmetric_key_id | int | ID of the key. Unique within the database. |
| key_length | int | Length of the key in bits. |
| key_algorithm | char(2) | Algorithm used with the key: R2 = RC2 R4 = RC4 D = DES D3 = Triple DES DT = TRIPLE_DES_3KEY DX = DESX A1 = AES 128 A2 = AES 192 A3 = AES 256 NA = EKM Key |
| algorithm_desc | nvarchar(60) | Description of the algorithm used with the key: RC2 RC4 DES Triple_DES TRIPLE_DES_3KEY DESX AES_128 AES_192 AES_256 NULL (Extensible Key Management algorithms only) |
| create_date | datetime | Date the key was created. |
| modify_date | datetime | Date the key was modified. |
| key_guid | uniqueidentifier | Globally unique identifier (GUID) associated with the key. It is auto-generated for persisted keys. GUIDs for temporary keys are derived from the user-supplied pass phrase. |
| key_thumbprint | sql_variant | SHA-1 hash of the key. The hash is globally unique. For non-Extensible Key Management keys this value will be NULL. |
| provider_type | nvarchar(120) | Type of cryptographic provider: CRYPTOGRAPHIC PROVIDER = Extensible Key Management keys NULL = Non-Extensible Key Management keys |
| cryptographic_provider_guid | uniqueidentifier | GUID for the cryptographic provider. For non-Extensible Key Management keys this value will be NULL. |
| cryptographic_provider_algid | sql_variant | Algorithm ID for the cryptographic provider. For non-Extensible Key Management keys this value will be NULL. |
Permissions
The visibility of the metadata in catalog views is limited to securables that a user either owns or on which the user has been granted some permission. For more information, see Metadata Visibility Configuration.
Remarks
The RC4 algorithm is deprecated. 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.
Note
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 2012 (11.x) material encrypted using RC4 or RC4_128 can be decrypted in any compatibility level.
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.
Fusionauth generate user api key in windows 10. Symmetric keys created with ALGORITHM = TRIPLE_DES use TRIPLE DES with a 128-bit key.
See Also
Catalog Views (Transact-SQL)
Extensible Key Management (EKM)
Security Catalog Views (Transact-SQL)
Encryption Hierarchy
CREATE SYMMETRIC KEY (Transact-SQL)