Package com.lambdaworks.crypto

Class SCrypt

java.lang.Object

com.lambdaworks.crypto.SCrypt

public class SCrypt
extends java.lang.Object

An implementation of the scrypt key derivation function. This class will attempt to load a native library containing the optimized C implementation from http://www.tarsnap.com/scrypt.html and fall back to the pure Java version if that fails.

Field Summary

Fields

Modifier and Type	Field	Description
private static boolean	native_library_loaded

Constructor Summary

Constructors

Constructor	Description
SCrypt()

Method Summary

Modifier and Type	Method	Description
static void	blockmix_salsa8(byte[] BY, int Bi, int Yi, int r)
static void	blockxor(byte[] S, int Si, byte[] D, int Di, int len)
static int	integerify(byte[] B, int Bi, int r)
static int	R(int a, int b)
static void	salsa20_8(byte[] B)
static byte[]	scrypt(byte[] passwd, byte[] salt, int N, int r, int p, int dkLen)	Implementation of the scrypt KDF.
static byte[]	scryptJ(byte[] passwd, byte[] salt, int N, int r, int p, int dkLen)	Pure Java implementation of the scrypt KDF.
static byte[]	scryptN(byte[] passwd, byte[] salt, int N, int r, int p, int dkLen)	Native C implementation of the scrypt KDF using the code from http://www.tarsnap.com/scrypt.html.
static void	smix(byte[] B, int Bi, int r, int N, byte[] V, byte[] XY)

Methods inherited from class java.lang.Object

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

Field Detail

native_library_loaded

private static final boolean native_library_loaded

Constructor Detail

SCrypt

public SCrypt()

Method Detail

scrypt

public static byte[] scrypt(byte[] passwd,
                            byte[] salt,
                            int N,
                            int r,
                            int p,
                            int dkLen)
                     throws java.security.GeneralSecurityException

Implementation of the scrypt KDF. Calls the native implementation scryptN(byte[], byte[], int, int, int, int) when the native library was successfully loaded, otherwise calls scryptJ(byte[], byte[], int, int, int, int).

Parameters:

passwd - Password.

salt - Salt.

N - CPU cost parameter.

r - Memory cost parameter.

p - Parallelization parameter.

dkLen - Intended length of the derived key.

Returns:

The derived key.

Throws:

java.security.GeneralSecurityException - when HMAC_SHA256 is not available.

scryptN

public static byte[] scryptN(byte[] passwd,
                             byte[] salt,
                             int N,
                             int r,
                             int p,
                             int dkLen)

Native C implementation of the scrypt KDF using the code from http://www.tarsnap.com/scrypt.html.

Parameters:

passwd - Password.

salt - Salt.

N - CPU cost parameter.

r - Memory cost parameter.

p - Parallelization parameter.

dkLen - Intended length of the derived key.

Returns:

The derived key.

scryptJ

public static byte[] scryptJ(byte[] passwd,
                             byte[] salt,
                             int N,
                             int r,
                             int p,
                             int dkLen)
                      throws java.security.GeneralSecurityException

Pure Java implementation of the scrypt KDF.

Parameters:

passwd - Password.

salt - Salt.

N - CPU cost parameter.

r - Memory cost parameter.

p - Parallelization parameter.

dkLen - Intended length of the derived key.

Returns:

The derived key.

Throws:

java.security.GeneralSecurityException - when HMAC_SHA256 is not available.

smix

public static void smix(byte[] B,
                        int Bi,
                        int r,
                        int N,
                        byte[] V,
                        byte[] XY)

blockmix_salsa8

public static void blockmix_salsa8(byte[] BY,
                                   int Bi,
                                   int Yi,
                                   int r)

R

public static int R(int a,
                    int b)

salsa20_8

public static void salsa20_8(byte[] B)

blockxor

public static void blockxor(byte[] S,
                            int Si,
                            byte[] D,
                            int Di,
                            int len)

integerify

public static int integerify(byte[] B,
                             int Bi,
                             int r)