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The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar
contains APIs for JDK 1.5 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one
provided with the Bouncy Castle Cryptography APIs.
package org.bouncycastle.crypto.prng;
import java.security.SecureRandom;
import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.CryptoServicesRegistrar;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.Mac;
import org.bouncycastle.crypto.engines.DESedeEngine;
import org.bouncycastle.crypto.macs.HMac;
import org.bouncycastle.crypto.prng.drbg.CTRSP800DRBG;
import org.bouncycastle.crypto.prng.drbg.HMacSP800DRBG;
import org.bouncycastle.crypto.prng.drbg.HashSP800DRBG;
import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
import org.bouncycastle.util.Arrays;
/**
* Builder class for making SecureRandom objects based on SP 800-90A Deterministic Random Bit Generators (DRBG).
*/
public class SP800SecureRandomBuilder
{
private final SecureRandom random;
private final EntropySourceProvider entropySourceProvider;
private byte[] personalizationString;
private int securityStrength = 256;
private int entropyBitsRequired = 256;
/**
* Basic constructor, creates a builder using an EntropySourceProvider based on the default SecureRandom with
* predictionResistant set to false.
*
* Any SecureRandom created from a builder constructed like this will make use of input passed to SecureRandom.setSeed() if
* the default SecureRandom does for its generateSeed() call.
*
*/
public SP800SecureRandomBuilder()
{
this(CryptoServicesRegistrar.getSecureRandom(), false);
}
/**
* Construct a builder with an EntropySourceProvider based on the passed in SecureRandom and the passed in value
* for prediction resistance.
*
* Any SecureRandom created from a builder constructed like this will make use of input passed to SecureRandom.setSeed() if
* the passed in SecureRandom does for its generateSeed() call.
*
* @param entropySource the SecureRandom acting as a source of entropy for DRBGs made by this builder.
* @param predictionResistant true if the SecureRandom seeder can be regarded as predictionResistant.
*/
public SP800SecureRandomBuilder(SecureRandom entropySource, boolean predictionResistant)
{
this.random = entropySource;
this.entropySourceProvider = new BasicEntropySourceProvider(random, predictionResistant);
}
/**
* Create a builder which makes creates the SecureRandom objects from a specified entropy source provider.
*
* Note: If this constructor is used any calls to setSeed() in the resulting SecureRandom will be ignored.
*
* @param entropySourceProvider a provider of EntropySource objects.
*/
public SP800SecureRandomBuilder(EntropySourceProvider entropySourceProvider)
{
this.random = null;
this.entropySourceProvider = entropySourceProvider;
}
/**
* Set the personalization string for DRBG SecureRandoms created by this builder
* @param personalizationString the personalisation string for the underlying DRBG.
* @return the current builder.
*/
public SP800SecureRandomBuilder setPersonalizationString(byte[] personalizationString)
{
this.personalizationString = Arrays.clone(personalizationString);
return this;
}
/**
* Set the security strength required for DRBGs used in building SecureRandom objects.
*
* @param securityStrength the security strength (in bits)
* @return the current builder.
*/
public SP800SecureRandomBuilder setSecurityStrength(int securityStrength)
{
this.securityStrength = securityStrength;
return this;
}
/**
* Set the amount of entropy bits required for seeding and reseeding DRBGs used in building SecureRandom objects.
*
* @param entropyBitsRequired the number of bits of entropy to be requested from the entropy source on each seed/reseed.
* @return the current builder.
*/
public SP800SecureRandomBuilder setEntropyBitsRequired(int entropyBitsRequired)
{
this.entropyBitsRequired = entropyBitsRequired;
return this;
}
/**
* Build a SecureRandom based on a SP 800-90A Hash DRBG.
*
* @param digest digest algorithm to use in the DRBG underneath the SecureRandom.
* @param nonce nonce value to use in DRBG construction.
* @param predictionResistant specify whether the underlying DRBG in the resulting SecureRandom should reseed on each request for bytes.
* @return a SecureRandom supported by a Hash DRBG.
*/
public SP800SecureRandom buildHash(Digest digest, byte[] nonce, boolean predictionResistant)
{
return new SP800SecureRandom(random, entropySourceProvider.get(entropyBitsRequired), new HashDRBGProvider(digest, nonce, personalizationString, securityStrength), predictionResistant);
}
/**
* Build a SecureRandom based on a SP 800-90A CTR DRBG.
*
* @param cipher the block cipher to base the DRBG on.
* @param keySizeInBits key size in bits to be used with the block cipher.
* @param nonce nonce value to use in DRBG construction.
* @param predictionResistant specify whether the underlying DRBG in the resulting SecureRandom should reseed on each request for bytes.
* @return a SecureRandom supported by a CTR DRBG.
*/
public SP800SecureRandom buildCTR(BlockCipher cipher, int keySizeInBits, byte[] nonce, boolean predictionResistant)
{
return new SP800SecureRandom(random, entropySourceProvider.get(entropyBitsRequired), new CTRDRBGProvider(cipher, keySizeInBits, nonce, personalizationString, securityStrength), predictionResistant);
}
/**
* Build a SecureRandom based on a SP 800-90A HMAC DRBG.
*
* @param hMac HMAC algorithm to use in the DRBG underneath the SecureRandom.
* @param nonce nonce value to use in DRBG construction.
* @param predictionResistant specify whether the underlying DRBG in the resulting SecureRandom should reseed on each request for bytes.
* @return a SecureRandom supported by a HMAC DRBG.
*/
public SP800SecureRandom buildHMAC(Mac hMac, byte[] nonce, boolean predictionResistant)
{
return new SP800SecureRandom(random, entropySourceProvider.get(entropyBitsRequired), new HMacDRBGProvider(hMac, nonce, personalizationString, securityStrength), predictionResistant);
}
private static class HashDRBGProvider
implements DRBGProvider
{
private final Digest digest;
private final byte[] nonce;
private final byte[] personalizationString;
private final int securityStrength;
public HashDRBGProvider(Digest digest, byte[] nonce, byte[] personalizationString, int securityStrength)
{
this.digest = digest;
this.nonce = nonce;
this.personalizationString = personalizationString;
this.securityStrength = securityStrength;
}
public String getAlgorithm()
{
return "HASH-DRBG-" + getSimplifiedName(digest);
}
public SP80090DRBG get(EntropySource entropySource)
{
return new HashSP800DRBG(digest, securityStrength, entropySource, personalizationString, nonce);
}
}
private static class HMacDRBGProvider
implements DRBGProvider
{
private final Mac hMac;
private final byte[] nonce;
private final byte[] personalizationString;
private final int securityStrength;
public HMacDRBGProvider(Mac hMac, byte[] nonce, byte[] personalizationString, int securityStrength)
{
this.hMac = hMac;
this.nonce = nonce;
this.personalizationString = personalizationString;
this.securityStrength = securityStrength;
}
public String getAlgorithm()
{
if (hMac instanceof HMac)
{
return "HMAC-DRBG-" + getSimplifiedName(((HMac)hMac).getUnderlyingDigest());
}
return "HMAC-DRBG-" + hMac.getAlgorithmName();
}
public SP80090DRBG get(EntropySource entropySource)
{
return new HMacSP800DRBG(hMac, securityStrength, entropySource, personalizationString, nonce);
}
}
private static class CTRDRBGProvider
implements DRBGProvider
{
private final BlockCipher blockCipher;
private final int keySizeInBits;
private final byte[] nonce;
private final byte[] personalizationString;
private final int securityStrength;
public CTRDRBGProvider(BlockCipher blockCipher, int keySizeInBits, byte[] nonce, byte[] personalizationString, int securityStrength)
{
this.blockCipher = blockCipher;
this.keySizeInBits = keySizeInBits;
this.nonce = nonce;
this.personalizationString = personalizationString;
this.securityStrength = securityStrength;
}
public String getAlgorithm()
{
if (blockCipher instanceof DESedeEngine)
{
return "CTR-DRBG-3KEY-TDES";
}
return "CTR-DRBG-" + blockCipher.getAlgorithmName() + keySizeInBits;
}
public SP80090DRBG get(EntropySource entropySource)
{
return new CTRSP800DRBG(blockCipher, keySizeInBits, securityStrength, entropySource, personalizationString, nonce);
}
}
private static String getSimplifiedName(Digest digest)
{
String name = digest.getAlgorithmName();
int dIndex = name.indexOf('-');
if (dIndex > 0 && !name.startsWith("SHA3"))
{
return name.substring(0, dIndex) + name.substring(dIndex + 1);
}
return name;
}
}