RSA

Class RSA

java.lang.Object
  RSA

All Implemented Interfaces:: AbstractRSA

public class RSA
extends Object
implements AbstractRSA
extends Object
implements AbstractRSA

Field Summary
`private BigInteger`	`d` The exponent used to decrypt in this RSA cryptosystem.
`private BigInteger`	`e` The exponent used to encrypt in this RSA cryptosystem.
`private BigInteger`	`n` The modulus used to encrypt or decrypt in this RSA cryptosystem.
`private static Random`	`rnd` An internal source of pseudo-randomness used by all instances.

Constructor Summary
`RSA(int numBits)` Constructs an RSA cryptosystem using a random modulus and exponents of specified bit length.
`RSA(String keyFile)` Constructs an RSA cryptosystem using a modulus and exponent read from a file.

Method Summary
`void`	`decrypt()` Decrypt the standard input stream using the modulus and exponent in this RSA cryptosystem.
`void`	`encrypt()` Encrypt the standard input stream using the modulus and exponent in this RSA cryptosystem.
`static void`	`main(String[] arguments)` Encrypts or decrypts by command-line arguments using an RSA cryptosystem.
`void`	`printKeys()` Print the keys in this RSA cryptosystem to the standard output stream.
`private static BigInteger`	`randomRelativePrime(BigInteger m)` Returns a random relative prime in the multiplicative group of units Z_m^*.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

d

private final BigInteger d

The exponent used to decrypt in this RSA cryptosystem.

e

private final BigInteger e

The exponent used to encrypt in this RSA cryptosystem.

n

private final BigInteger n

The modulus used to encrypt or decrypt in this RSA cryptosystem.

rnd

private static final Random rnd

An internal source of pseudo-randomness used by all instances.

Constructor Detail

RSA

public RSA(int numBits)

Constructs an RSA cryptosystem using a random modulus and exponents of specified bit length.

Parameters:: numBits - The number of bits in the modulus and exponents.

RSA

public RSA(String keyFile)
    throws FileNotFoundException,
           IOException

Constructs an RSA cryptosystem using a modulus and exponent read from a file.

Parameters:: keyFile - The name of a file containing a modulus and exponent.
Throws:: FileNotFoundException; IOException

Method Detail

decrypt

public void decrypt()
             throws IOException

Decrypt the standard input stream using the modulus and exponent in this RSA cryptosystem.

Specified by:: decrypt in interface AbstractRSA

Throws:: IOException

encrypt

public void encrypt()
             throws IOException

Encrypt the standard input stream using the modulus and exponent in this RSA cryptosystem.

Specified by:: encrypt in interface AbstractRSA

Throws:: IOException

main

public static void main(String[] arguments)
                 throws IOException

Encrypts or decrypts by command-line arguments using an RSA cryptosystem.

Parameters:

arguments - Command-line arguments controlling the cryptosystem.

The following arguments are meaningful, and have the following effects:

-g numBits

Print random keys of bit length numBits to the standard output stream.

-e keyFile

Encrypt the standard input stream using the modulus and exponent in the file named keyFile.

-d keyFile

Decrypt the standard input stream using the modulus and exponent in the file named keyFile.

Throws:

IOException - if an I/O error occurs.

printKeys

public void printKeys()

Print the keys in this RSA cryptosystem to the standard output stream.

Specified by:: printKeys in interface AbstractRSA

randomRelativePrime

private static BigInteger randomRelativePrime(BigInteger m)

Returns a random relative prime in the multiplicative group of units Z_m^*.

Parameters:: m - The modulus to which a random relative prime is returned.