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`java.lang.Object`

`gnu.java.security.key.dss.FIPS186`

An implementation of the DSA parameters generation as described in FIPS-186.

References:

Digital Signature Standard (DSS), Federal Information Processing Standards Publication 186. National Institute of Standards and Technology.

## Field Summary

`static int`

`static int`

`static int`

`static int`

`static int`

`static int`

## Constructor Summary

`FIPS186(int L, SecureRandom rnd)`

## Method Summary

`BigInteger[]`

`generateParameters()`

- This method generates the DSS
`p`

,`q`

, and`g`

parameters only when`L`

(the modulus length) is not one of the following:`512`

,`768`

and`1024`

.

### Methods inherited from class java.lang.Object

`clone`

,`equals`

,`extends Object> getClass`

,`finalize`

,`hashCode`

,`notify`

,`notifyAll`

,`toString`

,`wait`

,`wait`

,`wait`

public BigInteger[] generateParameters()

This method generates the DSS`p`

,`q`

, and`g`

parameters only when`L`

(the modulus length) is not one of the following:`512`

,`768`

and`1024`

. For those values of`L`

, this implementation uses pre-computed values of`p`

,`q`

, and`g`

given in the documentCryptoSpecincluded in the security guide documentation of the standard JDK distribution.The DSS requires two primes ,

`p`

and`q`

, satisfying the following three conditions:The algorithm used to find these primes is as described in FIPS-186, section 2.2: GENERATION OF PRIMES. This prime generation scheme starts by using the

`2`

^{159}< q < 2^{160}`2`

for a specified^{L-1}< p < 2^{L}`L`

, where`L = 512 + 64j`

for some`0 <= j <= 8`

- q divides p - 1.
`Sha160`

and a user suppliedSEEDto construct a prime,`q`

, in the range 2^{159}< q < 2^{160}. Once this is accomplished, the sameSEEDvalue is used to construct an`X`

in the range`2`

^{L-1 }< X < 2^{L}. The prime,`p`

, is then formed by rounding`X`

to a number congruent to`1 mod 2q`

. In this implementation we use the sameSEEDvalue given in FIPS-186, Appendix 5.

FIPS186.java --
Copyright 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
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