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package java.security.spec;

This immutable class specifies the set of parameters used for generating DSA parameters as specified in FIPS 186-3 Digital Signature Standard (DSS).
See Also:
  • AlgorithmParameterSpec
Since:1.8
/** * This immutable class specifies the set of parameters used for * generating DSA parameters as specified in * <a href="http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf">FIPS 186-3 Digital Signature Standard (DSS)</a>. * * @see AlgorithmParameterSpec * * @since 1.8 */
public final class DSAGenParameterSpec implements AlgorithmParameterSpec { private final int pLen; private final int qLen; private final int seedLen;
Creates a domain parameter specification for DSA parameter generation using primePLen and subprimeQLen. The value of subprimeQLen is also used as the default length of the domain parameter seed in bits.
Params:
  • primePLen – the desired length of the prime P in bits.
  • subprimeQLen – the desired length of the sub-prime Q in bits.
Throws:
/** * Creates a domain parameter specification for DSA parameter * generation using {@code primePLen} and {@code subprimeQLen}. * The value of {@code subprimeQLen} is also used as the default * length of the domain parameter seed in bits. * @param primePLen the desired length of the prime P in bits. * @param subprimeQLen the desired length of the sub-prime Q in bits. * @throws IllegalArgumentException if {@code primePLen} * or {@code subprimeQLen} is illegal per the specification of * FIPS 186-3. */
public DSAGenParameterSpec(int primePLen, int subprimeQLen) { this(primePLen, subprimeQLen, subprimeQLen); }
Creates a domain parameter specification for DSA parameter generation using primePLen, subprimeQLen, and seedLen.
Params:
  • primePLen – the desired length of the prime P in bits.
  • subprimeQLen – the desired length of the sub-prime Q in bits.
  • seedLen – the desired length of the domain parameter seed in bits, shall be equal to or greater than subprimeQLen.
Throws:
/** * Creates a domain parameter specification for DSA parameter * generation using {@code primePLen}, {@code subprimeQLen}, * and {@code seedLen}. * @param primePLen the desired length of the prime P in bits. * @param subprimeQLen the desired length of the sub-prime Q in bits. * @param seedLen the desired length of the domain parameter seed in bits, * shall be equal to or greater than {@code subprimeQLen}. * @throws IllegalArgumentException if {@code primePLenLen}, * {@code subprimeQLen}, or {@code seedLen} is illegal per the * specification of FIPS 186-3. */
public DSAGenParameterSpec(int primePLen, int subprimeQLen, int seedLen) { switch (primePLen) { case 1024: if (subprimeQLen != 160) { throw new IllegalArgumentException ("subprimeQLen must be 160 when primePLen=1024"); } break; case 2048: if (subprimeQLen != 224 && subprimeQLen != 256) { throw new IllegalArgumentException ("subprimeQLen must be 224 or 256 when primePLen=2048"); } break; case 3072: if (subprimeQLen != 256) { throw new IllegalArgumentException ("subprimeQLen must be 256 when primePLen=3072"); } break; default: throw new IllegalArgumentException ("primePLen must be 1024, 2048, or 3072"); } if (seedLen < subprimeQLen) { throw new IllegalArgumentException ("seedLen must be equal to or greater than subprimeQLen"); } this.pLen = primePLen; this.qLen = subprimeQLen; this.seedLen = seedLen; }
Returns the desired length of the prime P of the to-be-generated DSA domain parameters in bits.
Returns:the length of the prime P.
/** * Returns the desired length of the prime P of the * to-be-generated DSA domain parameters in bits. * @return the length of the prime P. */
public int getPrimePLength() { return pLen; }
Returns the desired length of the sub-prime Q of the to-be-generated DSA domain parameters in bits.
Returns:the length of the sub-prime Q.
/** * Returns the desired length of the sub-prime Q of the * to-be-generated DSA domain parameters in bits. * @return the length of the sub-prime Q. */
public int getSubprimeQLength() { return qLen; }
Returns the desired length of the domain parameter seed in bits.
Returns:the length of the domain parameter seed.
/** * Returns the desired length of the domain parameter seed in bits. * @return the length of the domain parameter seed. */
public int getSeedLength() { return seedLen; } }