http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5. 
public class org.bouncycastle.jce.provider.ElGamalUtil
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.bouncycastle.jce.provider.ElGamalUtil
  super_class: java.lang.Object
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.jce.provider.ElGamalUtil this
         0: .line 21
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // org.bouncycastle.jce.provider.ElGamalUtil this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/jce/provider/ElGamalUtil;

  public static org.bouncycastle.crypto.params.AsymmetricKeyParameter generatePublicKeyParameter(java.security.PublicKey);
    descriptor: (Ljava/security/PublicKey;)Lorg/bouncycastle/crypto/params/AsymmetricKeyParameter;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=7, locals=2, args_size=1
        start local 0 // java.security.PublicKey key
         0: .line 27
            aload 0 /* key */
            instanceof org.bouncycastle.jce.interfaces.ElGamalPublicKey
            ifeq 5
         1: .line 29
            aload 0 /* key */
            checkcast org.bouncycastle.jce.interfaces.ElGamalPublicKey
            astore 1 /* k */
        start local 1 // org.bouncycastle.jce.interfaces.ElGamalPublicKey k
         2: .line 31
            new org.bouncycastle.crypto.params.ElGamalPublicKeyParameters
            dup
            aload 1 /* k */
            invokeinterface org.bouncycastle.jce.interfaces.ElGamalPublicKey.getY:()Ljava/math/BigInteger;
         3: .line 32
            new org.bouncycastle.crypto.params.ElGamalParameters
            dup
            aload 1 /* k */
            invokeinterface org.bouncycastle.jce.interfaces.ElGamalPublicKey.getParameters:()Lorg/bouncycastle/jce/spec/ElGamalParameterSpec;
            invokevirtual org.bouncycastle.jce.spec.ElGamalParameterSpec.getP:()Ljava/math/BigInteger;
            aload 1 /* k */
            invokeinterface org.bouncycastle.jce.interfaces.ElGamalPublicKey.getParameters:()Lorg/bouncycastle/jce/spec/ElGamalParameterSpec;
            invokevirtual org.bouncycastle.jce.spec.ElGamalParameterSpec.getG:()Ljava/math/BigInteger;
            invokespecial org.bouncycastle.crypto.params.ElGamalParameters.<init>:(Ljava/math/BigInteger;Ljava/math/BigInteger;)V
         4: .line 31
            invokespecial org.bouncycastle.crypto.params.ElGamalPublicKeyParameters.<init>:(Ljava/math/BigInteger;Lorg/bouncycastle/crypto/params/ElGamalParameters;)V
            areturn
        end local 1 // org.bouncycastle.jce.interfaces.ElGamalPublicKey k
         5: .line 34
      StackMap locals:
      StackMap stack:
            aload 0 /* key */
            instanceof javax.crypto.interfaces.DHPublicKey
            ifeq 10
         6: .line 36
            aload 0 /* key */
            checkcast javax.crypto.interfaces.DHPublicKey
            astore 1 /* k */
        start local 1 // javax.crypto.interfaces.DHPublicKey k
         7: .line 38
            new org.bouncycastle.crypto.params.ElGamalPublicKeyParameters
            dup
            aload 1 /* k */
            invokeinterface javax.crypto.interfaces.DHPublicKey.getY:()Ljava/math/BigInteger;
         8: .line 39
            new org.bouncycastle.crypto.params.ElGamalParameters
            dup
            aload 1 /* k */
            invokeinterface javax.crypto.interfaces.DHPublicKey.getParams:()Ljavax/crypto/spec/DHParameterSpec;
            invokevirtual javax.crypto.spec.DHParameterSpec.getP:()Ljava/math/BigInteger;
            aload 1 /* k */
            invokeinterface javax.crypto.interfaces.DHPublicKey.getParams:()Ljavax/crypto/spec/DHParameterSpec;
            invokevirtual javax.crypto.spec.DHParameterSpec.getG:()Ljava/math/BigInteger;
            invokespecial org.bouncycastle.crypto.params.ElGamalParameters.<init>:(Ljava/math/BigInteger;Ljava/math/BigInteger;)V
         9: .line 38
            invokespecial org.bouncycastle.crypto.params.ElGamalPublicKeyParameters.<init>:(Ljava/math/BigInteger;Lorg/bouncycastle/crypto/params/ElGamalParameters;)V
            areturn
        end local 1 // javax.crypto.interfaces.DHPublicKey k
        10: .line 42
      StackMap locals:
      StackMap stack:
            new java.security.InvalidKeyException
            dup
            ldc "can't identify public key for El Gamal."
            invokespecial java.security.InvalidKeyException.<init>:(Ljava/lang/String;)V
            athrow
        end local 0 // java.security.PublicKey key
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0   11     0   key  Ljava/security/PublicKey;
            2    5     1     k  Lorg/bouncycastle/jce/interfaces/ElGamalPublicKey;
            7   10     1     k  Ljavax/crypto/interfaces/DHPublicKey;
    Exceptions:
      throws java.security.InvalidKeyException
    MethodParameters:
      Name  Flags
      key   

  public static org.bouncycastle.crypto.params.AsymmetricKeyParameter generatePrivateKeyParameter(java.security.PrivateKey);
    descriptor: (Ljava/security/PrivateKey;)Lorg/bouncycastle/crypto/params/AsymmetricKeyParameter;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=7, locals=2, args_size=1
        start local 0 // java.security.PrivateKey key
         0: .line 49
            aload 0 /* key */
            instanceof org.bouncycastle.jce.interfaces.ElGamalPrivateKey
            ifeq 5
         1: .line 51
            aload 0 /* key */
            checkcast org.bouncycastle.jce.interfaces.ElGamalPrivateKey
            astore 1 /* k */
        start local 1 // org.bouncycastle.jce.interfaces.ElGamalPrivateKey k
         2: .line 53
            new org.bouncycastle.crypto.params.ElGamalPrivateKeyParameters
            dup
            aload 1 /* k */
            invokeinterface org.bouncycastle.jce.interfaces.ElGamalPrivateKey.getX:()Ljava/math/BigInteger;
         3: .line 54
            new org.bouncycastle.crypto.params.ElGamalParameters
            dup
            aload 1 /* k */
            invokeinterface org.bouncycastle.jce.interfaces.ElGamalPrivateKey.getParameters:()Lorg/bouncycastle/jce/spec/ElGamalParameterSpec;
            invokevirtual org.bouncycastle.jce.spec.ElGamalParameterSpec.getP:()Ljava/math/BigInteger;
            aload 1 /* k */
            invokeinterface org.bouncycastle.jce.interfaces.ElGamalPrivateKey.getParameters:()Lorg/bouncycastle/jce/spec/ElGamalParameterSpec;
            invokevirtual org.bouncycastle.jce.spec.ElGamalParameterSpec.getG:()Ljava/math/BigInteger;
            invokespecial org.bouncycastle.crypto.params.ElGamalParameters.<init>:(Ljava/math/BigInteger;Ljava/math/BigInteger;)V
         4: .line 53
            invokespecial org.bouncycastle.crypto.params.ElGamalPrivateKeyParameters.<init>:(Ljava/math/BigInteger;Lorg/bouncycastle/crypto/params/ElGamalParameters;)V
            areturn
        end local 1 // org.bouncycastle.jce.interfaces.ElGamalPrivateKey k
         5: .line 56
      StackMap locals:
      StackMap stack:
            aload 0 /* key */
            instanceof javax.crypto.interfaces.DHPrivateKey
            ifeq 10
         6: .line 58
            aload 0 /* key */
            checkcast javax.crypto.interfaces.DHPrivateKey
            astore 1 /* k */
        start local 1 // javax.crypto.interfaces.DHPrivateKey k
         7: .line 60
            new org.bouncycastle.crypto.params.ElGamalPrivateKeyParameters
            dup
            aload 1 /* k */
            invokeinterface javax.crypto.interfaces.DHPrivateKey.getX:()Ljava/math/BigInteger;
         8: .line 61
            new org.bouncycastle.crypto.params.ElGamalParameters
            dup
            aload 1 /* k */
            invokeinterface javax.crypto.interfaces.DHPrivateKey.getParams:()Ljavax/crypto/spec/DHParameterSpec;
            invokevirtual javax.crypto.spec.DHParameterSpec.getP:()Ljava/math/BigInteger;
            aload 1 /* k */
            invokeinterface javax.crypto.interfaces.DHPrivateKey.getParams:()Ljavax/crypto/spec/DHParameterSpec;
            invokevirtual javax.crypto.spec.DHParameterSpec.getG:()Ljava/math/BigInteger;
            invokespecial org.bouncycastle.crypto.params.ElGamalParameters.<init>:(Ljava/math/BigInteger;Ljava/math/BigInteger;)V
         9: .line 60
            invokespecial org.bouncycastle.crypto.params.ElGamalPrivateKeyParameters.<init>:(Ljava/math/BigInteger;Lorg/bouncycastle/crypto/params/ElGamalParameters;)V
            areturn
        end local 1 // javax.crypto.interfaces.DHPrivateKey k
        10: .line 64
      StackMap locals:
      StackMap stack:
            new java.security.InvalidKeyException
            dup
            ldc "can't identify private key for El Gamal."
            invokespecial java.security.InvalidKeyException.<init>:(Ljava/lang/String;)V
            athrow
        end local 0 // java.security.PrivateKey key
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0   11     0   key  Ljava/security/PrivateKey;
            2    5     1     k  Lorg/bouncycastle/jce/interfaces/ElGamalPrivateKey;
            7   10     1     k  Ljavax/crypto/interfaces/DHPrivateKey;
    Exceptions:
      throws java.security.InvalidKeyException
    MethodParameters:
      Name  Flags
      key   
}
SourceFile: "ElGamalUtil.java"