Php Generate Random Session Key

Learn how a TLS handshake enables clients and servers to create session keys. An SSL session key is used for symmetric encryption in the TLS protocol. Learn how a TLS handshake enables clients and servers to create session keys. The 'server random': This is similar to the client random, except that the server sends it to the client. 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. Oct 04, 2018  The server generates a unique random number, which is called a session id. It also creates a new file on the server which is used to store the session-specific information. Next, a session id is passed back to the user, along with whatever resource was requested.

The calling application must specify the algorithm when calling this function. Because this algorithm type is kept bundled with the key, the application does not need to specify the algorithm later when the actual cryptographic operations are performed.

Syntax

Parameters

hProv

A handle to a cryptographic service provider (CSP) created by a call toCryptAcquireContext.

Algid

AnALG_ID value that identifies the algorithm for which the key is to be generated. Values for this parameter vary depending on the CSP used.

For ALG_ID values to use with the Microsoft Base Cryptographic Provider, seeBase Provider Algorithms.

For ALG_ID values to use with the Microsoft Strong Cryptographic Provider or the Microsoft Enhanced Cryptographic Provider, seeEnhanced Provider Algorithms.

For a Diffie-Hellman CSP, use one of the following values.

In addition to generating session keys for symmetric algorithms, this function can also generate public/private key pairs. Each CryptoAPI client generally possesses two public/private key pairs. To generate one of these key pairs, set the Algid parameter to one of the following values.

Php Generate Random Session Key Error

dwFlags

Specifies the type of key generated. The sizes of a session key, RSA signature key, and RSA key exchange keys can be set when the key is generated. The key size, representing the length of the key modulus in bits, is set with the upper 16 bits of this parameter. Thus, if a 2,048-bit RSA signature key is to be generated, the value 0x08000000 is combined with any other dwFlags predefined value with a bitwise-OR operation. The upper 16 bits of 0x08000000 is 0x0800, or decimal 2,048. The RSA1024BIT_KEY value can be used to specify a 1024-bit RSA key.

Due to changing export control restrictions, the default CSP and default key length may change between operating system versions. It is important that both the encryption and decryption use the same CSP and that the key length be explicitly set using the dwFlags parameter to ensure interoperability on different operating system platforms.

In particular, the default RSA Full Cryptographic Service Provider is the Microsoft RSA Strong Cryptographic Provider. The default DSS Signature Diffie-Hellman Cryptographic Service Provider is the Microsoft Enhanced DSS Diffie-Hellman Cryptographic Provider. Each of these CSPs has a default 128-bit symmetric key length for RC2 and RC4 and a 1,024-bit default key length for public key algorithms.

If the upper 16 bits is zero, the default key size is generated. If a key larger than the maximum or smaller than the minimum is specified, the call fails with the ERROR_INVALID_PARAMETER code.

The following table lists minimum, default, and maximum signature and exchange key lengths beginning with Windows XP.

For session key lengths, see CryptDeriveKey.

For more information about keys generated using Microsoft providers, seeMicrosoft Cryptographic Service Providers.

The lower 16-bits of this parameter can be zero or a combination of one or more of the following values.

phKey

Address to which the function copies the handle of the newly generated key. When you have finished using the key, delete the handle to the key by calling the CryptDestroyKey function.

Return value

Returns nonzero if successful or zero otherwise.

For extended error information, callGetLastError.

The error codes prefaced by 'NTE' are generated by the particular CSP being used. Some possible error codes are listed in the following table.

Remarks

If keys are generated for symmetricblock ciphers, the key, by default, is set up in cipher block chaining (CBC) mode with an initialization vector of zero. This cipher mode provides a good default method for bulk encrypting data. To change these parameters, use theCryptSetKeyParam function.

To choose an appropriate key length, the following methods are recommended:

• Enumerate the algorithms that the CSP supports and get maximum and minimum key lengths for each algorithm. To do this, call CryptGetProvParam with PP_ENUMALGS_EX.
• Use the minimum and maximum lengths to choose an appropriate key length. It is not always advisable to choose the maximum length because this can lead to performance issues.
• After the desired key length has been chosen, use the upper 16 bits of the dwFlags parameter to specify the key length.

Examples

Php Generate Random Session Key In Word

The following example shows the creation of a random session key. For an example that includes the complete context for this example, see Example C Program: Encrypting a File. For another example that uses this function, see Example C Program: Decrypting a File.

Requirements

See also