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HashInit(<algo>, [<options>], [<key>])

Description

Initializes a hash context for subsequent hashing operations. The function supports various hash algorithms and optional parameters, allowing for flexibility in hash computation.

Parameters

<algo> The hash algorithm to use.
<options> Optional. Hashing options, defaults to @HashOptDefault.
<key> Optional. Only used if <options> is set to @HashOptHMac.

Return Value

Success: Returns hash context that can be used for subsequent hashing operations.
Failure: Returns null.

Remarks

This function is a preparatory step for hashing data using different algorithms and options. It sets up the hash context based on the specified algorithm and options, preparing it for subsequent data input.

See HashAlgos and Hash for a list of hashes.

Related

HashUpdate, HashFinal, HashCopy, HashUpdateFile, HashUpdateStream

Example

Example of usage:

my $hash = HashInit("gost");
HashUpdate($hash, "Cat");
say HashFinal($hash);

my $hash = HashInit("gost");
HashUpdate($hash, "Cat");
HashUpdate($hash, "Dog");
say HashFinal($hash);

// PRINTS
// CEA32112D34163EB607E8F19CC8C8E2D2B11268088D35F71757AABA6A11D40B8
// 5D32789DD6F8F25FBDEE44F875FABC1556AE8A97F3619EE8CE04D548595D0973

In the given example, two hash computations are showcased using the GOST hash algorithm in Sputnik. In the first instance, the hash context is initialized with the string "Cat," and the resulting hash is calculated and printed. In the second case, the same hash context is updated with an additional string, "Dog," before finalizing and printing the resulting hash. The hash values demonstrate the unique fingerprints generated by the GOST algorithm for the given input data. The ability to update the hash context allows for the incremental hashing of data, and each distinct input produces a different hash output, highlighting the cryptographic strength of the GOST hash function.

Using the HMac:

my $hash = HashInit("gost", @HashOptHMac, "secretKey");
HashUpdate($hash, "Cat");
HashUpdate($hash, "Dog");
say HashFinal($hash);

// PRINTS
// 56FAFEECA6A4A191D893A4E0C34EBA828AC30F9D46D38CDECE6A15E949478DA4

In this example, a hash context is initialized using the GOST hash algorithm with HMAC (Hash-Based Message Authentication Code) enabled by specifying @HashOptHMac as an option. The HMAC requires a secret key, in this case, "secretKey." The HashUpdate function is then used to update the hash context with the strings "Cat" and "Dog." Finally, HashFinal is called to obtain the resulting hash value. The output, "56FAFEECA6A4A191D893A4E0C34EBA828AC30F9D46D38CDECE6A15E949478DA4," represents the GOST hash of the concatenated strings "Cat" and "Dog" with the specified secret key. This demonstrates the usage of HMAC for secure hash computations with a shared secret key.


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