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HashPBKDF2(<algo>, <password>, <salt>, [<iterations>], [<length>], [<rawOutput>])


Derives a key from the provided password and salt using the Password-Based Key Derivation Function 2 (PBKDF2) with the specified algorithm.


<algo> The hash algorithm to use (e.g., "sha256", "md5").
<password> The binary password from which the key is derived.
<salt> The binary salt used in the key derivation process.
[<iterations>] Optional. The number of iterations for the key derivation. Defaults to 1 if not provided.
[<length>] Optional. The length of the derived key in bytes or hex characters (if rawOutput is false). Defaults to the size of the algorithm if not given.
[<rawOutput>] Optional. If set to true, returns a binary key; otherwise, returns a string key. Defaults to false (string key).

Return Value

Success: Returns the derived key as either a string or binary, based on the rawOutput parameter.
Failure: Returns an empty string or binary (depending on <rawOutput>) if the hashing process encounters an issue.


The HashPBKDF2 function applies the PBKDF2 algorithm to securely derive a key from the provided password and salt. The number of iterations and key length can be customized for increased security.

Understanding Hash Collisions and Safeguarding Hash Functions:

In the realm of cryptography, a hash collision occurs when two different inputs produce the same hash output. While cryptographic hash functions are designed to be one-way and deterministic, the possibility of collisions exists due to the finite nature of hash values compared to the infinite input space. Attackers may exploit hash collisions to undermine the integrity and security of systems, especially when dealing with processes like password hashing and key derivation.

Hash functions such as HashPBKDF2 are susceptible to collision attacks if implemented improperly or with weak parameters. Adversaries often employ techniques like brute force attacks, where they systematically test a large number of inputs to find two that produce the same hash value. To defend against such attacks, it is crucial to follow best practices when using hash functions, especially in scenarios like password hashing and key derivation.

Proper Use to Mitigate Collision Risks:

  1. Unique Salts: Incorporate unique salts for each hashed value. Salts act as randomization factors, making precomputed tables (rainbow tables) ineffective and significantly increasing the complexity of collision attacks.
  2. Algorithm Selection: Choose a robust and widely accepted hash algorithm. Algorithms like SHA-256 or SHA-3 are recommended due to their resistance against collision attacks and continuous scrutiny by the cryptographic community.
  3. Iterations: Increase the number of iterations when using iterative hash functions like HashPBKDF2. Higher iteration counts slow down attackers attempting brute force or dictionary attacks, making collision discovery more time-consuming.
  4. Secure Storage: Safeguard the generated salts and hashed values in a secure environment. Avoid exposing salts or hash outputs, as this information can

See HashAlgos and Hash for a list of hashes.



Example of usage:

say HashPBKDF2("whirlpool", "password", "salt", 256, 32);
// C00505EF3A6F569C357ECAB68B86590F

This example illustrates the basic usage of HashPBKDF2 using the Whirlpool hash algorithm. It derives a key from the password "password" and the salt "salt" with 256 iterations, resulting in a 32-byte key. The say statement prints the derived key.

A more secure example:

my $password = "T1829quick brown fox(XTy88?)";
my $salt = B"\x6F\x17\xCD\xDE\xF7\xD6\x38\x44\x90\x1B\x29\x77\xB7\x61\x0E\xF3";
say HashPBKDF2("gost", $password, $salt, 32767, 32);
// AD7C77804F1D0355D04B43858CBF069E

This example showcases a highly secure usage of HashPBKDF2. It uses the GOST hash algorithm, a strong password, and a pre-generated salt for increased security. The password is secure and strong, and the salt is a binary string. The function applies 32,767 iterations to derive a 32-byte key. This approach enhances security by leveraging a complex password, a unique salt, and a robust hashing algorithm.

These examples demonstrate how HashPBKDF2 allows customization of hashing parameters, making it adaptable to different security requirements. The second example, in particular, showcases practices for enhancing security through the use of a strong password, a unique salt, and a secure hashing algorithm.

A quick example on how to get a perfect salt:

// Cryptographically secure generate 16 bytes then do additional rounds on it
my $salt = EscapeBytes(RandomSeedBin(16, true));
say "Here is your new secure salt to copy and paste in a script";
say "my \$salt = B\"$salt\";";
// Here is your new secure salt to copy and paste in a script
// my $salt = B"\x50\x73\x00\x0E\xB9\x9A\xA7\x6B\x81\xC0\x7B\x9E\x3A\xA9\xB1\xE6";

In this example, a secure and convenient method for generating a cryptographic salt in Sputnik is demonstrated. The code utilizes the RandomSeedBin function to generate 16 cryptographically secure random bytes, ensuring a strong foundation for the salt. The resulting binary data is then processed by EscapeBytes to create a representation suitable for inclusion in a script. The generated salt is printed with a message encouraging users to copy and paste it directly into their scripts. Additionally, it's important to note that the size of the salt can be adjusted based on security preferences. While 16 bytes is the minimal recommended value, users have the flexibility to increase the size to 32, 64, or beyond for enhanced security. This adaptable approach allows users to customize the salt length according to their specific cryptographic requirements.

It is crucial to emphasize that the generated salt, being an integral component of cryptographic processes, must be treated as confidential information. The purpose of the salt is to enhance security by making it more challenging for adversaries to discover hash collisions. Keeping the salt secure and undisclosed significantly contributes to the effectiveness of cryptographic mechanisms. Exposing or sharing the salt diminishes its purpose and compromises the security benefits it provides. Therefore, it is imperative to handle and store the salt with the same level of confidentiality as sensitive cryptographic keys.

Cheryl (uberfox@hotmail.com)