Package pl.edu.icm.unity.stdext.credential.pass

Class SCryptEncoder

java.lang.Object

pl.edu.icm.unity.stdext.credential.pass.SCryptEncoder

public class SCryptEncoder
extends Object

Uses scrypt to encode passwords. The class limits number of concurrent encodings so that we can have a control about the total memory use by scrypt. Scrypt memory appetite is: 128 bytes × 2^workFactor × blockSize. With default block size of 8, it is 1024 x 2^workfactor.

Constructor Summary

Constructors

Constructor	Description
SCryptEncoder(ForkJoinPool pool)

Method Summary

Modifier and Type	Method	Description
int	getMaxAllowedWorkFactor()	Computes a max currently considered safe work factor, taking into account the heap memory available for the VM and the configured number of allowed concurrent password checks.
byte[]	scrypt(String password, byte[] salt, ScryptParams params)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SCryptEncoder

public SCryptEncoder(ForkJoinPool pool)

Method Details

getMaxAllowedWorkFactor

public int getMaxAllowedWorkFactor()

Computes a max currently considered safe work factor, taking into account the heap memory available for the VM and the configured number of allowed concurrent password checks. Algorithm assumes 0.5G heap reserved for other purposes then password hashing (pretty arbitrary number, typically well enough, but may happen this is to low).

Returns:

max WF so that 1024*2^WF invalid input: '<' MAX_AVAILABLE_HEAP - 500MB

scrypt

public byte[] scrypt(String password,
 byte[] salt,
 ScryptParams params)