org.metastatic.jessie.provider

Class CSPRNG

BasePRNG
- org.metastatic.jessie.provider.CSPRNG

public class CSPRNG

extends BasePRNG

An entropy pool-based pseudo-random number generator based on the PRNG in Peter Gutmann's cryptlib (http://www.cs.auckland.ac.nz/~pgut001/cryptlib/).

The basic properties of this generator are:

The internal state cannot be determined by knowledge of the input.
It is resistant to bias introduced by specific inputs.
The output does not reveal the state of the generator.

Field Summary
`static String`	`BLOCKING` Property name for whether or not to wait for the slow poll to complete, passed as a `Boolean`.
`static String`	`FILE_SOURCES` Property name for the list of files to read for random values.
`static String`	`OTHER_SOURCES` Property name for a list of other sources of entropy.
`static String`	`PROGRAM_SOURCES` Property name for the list of programs to execute, and use the output as new random bytes.
`static String`	`URL_SOURCES` Property name for the list of URLs to poll for random values.

Constructor Summary
`CSPRNG()`

Method Summary
`void`	`addRandomByte(byte b)` Add a single random byte to the randomness pool.
`void`	`addRandomBytes(byte[] buf, int off, int len)` Add an array of bytes into the randomness pool.
`Object`	`clone()`
`void`	`fillBlock()`
`protected void`	`finalize()`
`static CSPRNG`	`getSystemInstance()` Create and initialize a CSPRNG instance with the "system" parameters; the files, URLs, programs, and `EntropySource` sources used by the instance are derived from properties set in the system `Properties`.
`byte`	`nextByte()`
`void`	`nextBytes(byte[] out, int offset, int length)`
`void`	`setup(Map attrib)`

BLOCKING

public static final String BLOCKING

Property name for whether or not to wait for the slow poll to complete, passed as a Boolean. The default value is true.

FILE_SOURCES

public static final String FILE_SOURCES

Property name for the list of files to read for random values. The mapped value is a list with the following values:
A Double, indicating the suggested quality of this source. This value must be between 0 and 100.
An Integer, indicating the number of bytes to skip in the file before reading bytes. This can be any nonnegative value.
An Integer, indicating the number of bytes to read.
A String, indicating the path to the file.

See Also:
gnu.crypto.util.SimpleList

OTHER_SOURCES

public static final String OTHER_SOURCES

Property name for a list of other sources of entropy. The mapped value must be a list of EntropySource objects.

PROGRAM_SOURCES

public static final String PROGRAM_SOURCES

Property name for the list of programs to execute, and use the output as new random bytes. The mapped property is formatted similarly an in FILE_SOURCES and URL_SOURCES, except the fourth member is a String of the program to execute.

URL_SOURCES

public static final String URL_SOURCES

Property name for the list of URLs to poll for random values. The mapped value is a list formatted similarly as in FILE_SOURCES, but the fourth member is a URL.

CSPRNG

public CSPRNG()

addRandomByte

public void addRandomByte(byte b)

Add a single random byte to the randomness pool. Note that this method will not increment the pool's quality counter (this can only be done via a source provided to the setup method).
Parameters:
b - The byte to add.

addRandomBytes

public void addRandomBytes(byte[] buf,
                           int off,
                           int len)

Add an array of bytes into the randomness pool. Note that this method will not increment the pool's quality counter (this can only be done via a source provided to the setup method).
Parameters:
buf - The byte array.
off - The offset from whence to start reading bytes.
len - The number of bytes to add.

clone

public Object clone()

fillBlock

public void fillBlock()
            throws LimitReachedException

finalize

protected void finalize()
            throws Throwable

getSystemInstance

public static CSPRNG getSystemInstance()
            throws ClassNotFoundException,
                   MalformedURLException,
                   NumberFormatException

Create and initialize a CSPRNG instance with the "system" parameters; the files, URLs, programs, and EntropySource sources used by the instance are derived from properties set in the system Properties.
All properties are of the from name.N, where name is the name of the source, and N is an integer (staring at 1) that indicates the preference number for that source.
The following vales for name are used here:

FILE_SOURCES
quality ; offset ; count ; path
FILE_SOURCES

URL_SOURCESpath

PROGRAM_SOURCES

OTHER_SOURCESEntropySource

Finally, a boolean property "jessie.csprng.blocking" can be set to the desired value of BLOCKING.
An example of valid properties would be:
 jessie.csprng.blocking=true

 jessie.csprng.file.1=75.0;0;256;/dev/random
 jessie.csprng.file.2=10.0;0;100;/home/user/file

 jessie.csprng.url.1=5.0;0;256;http://www.random.org/cgi-bin/randbyte?nbytes=256
 jessie.csprng.url.2=0;256;256;http://slashdot.org/

 jessie.csprng.program.1=0.5;0;10;last -n 50
 jessie.csprng.program.2=0.5;0;10;tcpdump -c 5

 jessie.csprng.other.1=foo.bar.MyEntropySource
 jessie.csprng.other.2=com.company.OtherEntropySource
 

nextByte

public byte nextByte()
            throws LimitReachedException

nextBytes

public void nextBytes(byte[] out,
                      int offset,
                      int length)
            throws LimitReachedException

setup

public void setup(Map attrib)

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