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author | Roberto Tyley <roberto.tyley@gmail.com> | 2014-07-15 01:38:01 +0400 |
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committer | Roberto Tyley <roberto.tyley@gmail.com> | 2014-07-26 11:23:17 +0400 |
commit | 7cb752aaf746dc0b473afeb9e892b7fbc12666c5 (patch) | |
tree | cc4f91ddc18332b5adbe82e3fcb040d976c90105 /core/src/main/java/org/spongycastle/crypto/generators/ElGamalKeyPairGenerator.java | |
parent | 551830f8ea5177042af2c7dd1fc90888bc67387d (diff) |
Execute become-spongy.sh
https://github.com/rtyley/spongycastle/blob/3040af/become-spongy.sh
Diffstat (limited to 'core/src/main/java/org/spongycastle/crypto/generators/ElGamalKeyPairGenerator.java')
-rw-r--r-- | core/src/main/java/org/spongycastle/crypto/generators/ElGamalKeyPairGenerator.java | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/crypto/generators/ElGamalKeyPairGenerator.java b/core/src/main/java/org/spongycastle/crypto/generators/ElGamalKeyPairGenerator.java new file mode 100644 index 00000000..cb0a9fcf --- /dev/null +++ b/core/src/main/java/org/spongycastle/crypto/generators/ElGamalKeyPairGenerator.java @@ -0,0 +1,44 @@ +package org.spongycastle.crypto.generators; + +import java.math.BigInteger; + +import org.spongycastle.crypto.AsymmetricCipherKeyPair; +import org.spongycastle.crypto.AsymmetricCipherKeyPairGenerator; +import org.spongycastle.crypto.KeyGenerationParameters; +import org.spongycastle.crypto.params.DHParameters; +import org.spongycastle.crypto.params.ElGamalKeyGenerationParameters; +import org.spongycastle.crypto.params.ElGamalParameters; +import org.spongycastle.crypto.params.ElGamalPrivateKeyParameters; +import org.spongycastle.crypto.params.ElGamalPublicKeyParameters; + +/** + * a ElGamal key pair generator. + * <p> + * This generates keys consistent for use with ElGamal as described in + * page 164 of "Handbook of Applied Cryptography". + */ +public class ElGamalKeyPairGenerator + implements AsymmetricCipherKeyPairGenerator +{ + private ElGamalKeyGenerationParameters param; + + public void init( + KeyGenerationParameters param) + { + this.param = (ElGamalKeyGenerationParameters)param; + } + + public AsymmetricCipherKeyPair generateKeyPair() + { + DHKeyGeneratorHelper helper = DHKeyGeneratorHelper.INSTANCE; + ElGamalParameters egp = param.getParameters(); + DHParameters dhp = new DHParameters(egp.getP(), egp.getG(), null, egp.getL()); + + BigInteger x = helper.calculatePrivate(dhp, param.getRandom()); + BigInteger y = helper.calculatePublic(dhp, x); + + return new AsymmetricCipherKeyPair( + new ElGamalPublicKeyParameters(y, egp), + new ElGamalPrivateKeyParameters(x, egp)); + } +} |