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. 
class org.bouncycastle.crypto.engines.RSACoreEngine
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: org.bouncycastle.crypto.engines.RSACoreEngine
  super_class: java.lang.Object
{
  private org.bouncycastle.crypto.params.RSAKeyParameters key;
    descriptor: Lorg/bouncycastle/crypto/params/RSAKeyParameters;
    flags: (0x0002) ACC_PRIVATE

  private boolean forEncryption;
    descriptor: Z
    flags: (0x0002) ACC_PRIVATE

  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
         0: .line 14
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;

  public void init(boolean, org.bouncycastle.crypto.CipherParameters);
    descriptor: (ZLorg/bouncycastle/crypto/CipherParameters;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=4, args_size=3
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
        start local 1 // boolean forEncryption
        start local 2 // org.bouncycastle.crypto.CipherParameters param
         0: .line 29
            aload 2 /* param */
            instanceof org.bouncycastle.crypto.params.ParametersWithRandom
            ifeq 4
         1: .line 31
            aload 2 /* param */
            checkcast org.bouncycastle.crypto.params.ParametersWithRandom
            astore 3 /* rParam */
        start local 3 // org.bouncycastle.crypto.params.ParametersWithRandom rParam
         2: .line 33
            aload 0 /* this */
            aload 3 /* rParam */
            invokevirtual org.bouncycastle.crypto.params.ParametersWithRandom.getParameters:()Lorg/bouncycastle/crypto/CipherParameters;
            checkcast org.bouncycastle.crypto.params.RSAKeyParameters
            putfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
        end local 3 // org.bouncycastle.crypto.params.ParametersWithRandom rParam
         3: .line 34
            goto 5
         4: .line 37
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 2 /* param */
            checkcast org.bouncycastle.crypto.params.RSAKeyParameters
            putfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
         5: .line 40
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            iload 1 /* forEncryption */
            putfield org.bouncycastle.crypto.engines.RSACoreEngine.forEncryption:Z
         6: .line 41
            return
        end local 2 // org.bouncycastle.crypto.CipherParameters param
        end local 1 // boolean forEncryption
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot           Name  Signature
            0    7     0           this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;
            0    7     1  forEncryption  Z
            0    7     2          param  Lorg/bouncycastle/crypto/CipherParameters;
            2    3     3         rParam  Lorg/bouncycastle/crypto/params/ParametersWithRandom;
    MethodParameters:
               Name  Flags
      forEncryption  
      param          

  public int getInputBlockSize();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=1
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
         0: .line 52
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            invokevirtual org.bouncycastle.crypto.params.RSAKeyParameters.getModulus:()Ljava/math/BigInteger;
            invokevirtual java.math.BigInteger.bitLength:()I
            istore 1 /* bitSize */
        start local 1 // int bitSize
         1: .line 54
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.forEncryption:Z
            ifeq 3
         2: .line 56
            iload 1 /* bitSize */
            bipush 7
            iadd
            bipush 8
            idiv
            iconst_1
            isub
            ireturn
         3: .line 60
      StackMap locals: int
      StackMap stack:
            iload 1 /* bitSize */
            bipush 7
            iadd
            bipush 8
            idiv
            ireturn
        end local 1 // int bitSize
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    4     0     this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;
            1    4     1  bitSize  I

  public int getOutputBlockSize();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=1
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
         0: .line 73
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            invokevirtual org.bouncycastle.crypto.params.RSAKeyParameters.getModulus:()Ljava/math/BigInteger;
            invokevirtual java.math.BigInteger.bitLength:()I
            istore 1 /* bitSize */
        start local 1 // int bitSize
         1: .line 75
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.forEncryption:Z
            ifeq 3
         2: .line 77
            iload 1 /* bitSize */
            bipush 7
            iadd
            bipush 8
            idiv
            ireturn
         3: .line 81
      StackMap locals: int
      StackMap stack:
            iload 1 /* bitSize */
            bipush 7
            iadd
            bipush 8
            idiv
            iconst_1
            isub
            ireturn
        end local 1 // int bitSize
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    4     0     this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;
            1    4     1  bitSize  I

  public java.math.BigInteger convertInput(byte[], int, int);
    descriptor: ([BII)Ljava/math/BigInteger;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=6, args_size=4
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // int inLen
         0: .line 90
            iload 3 /* inLen */
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.engines.RSACoreEngine.getInputBlockSize:()I
            iconst_1
            iadd
            if_icmple 2
         1: .line 92
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "input too large for RSA cipher."
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         2: .line 94
      StackMap locals:
      StackMap stack:
            iload 3 /* inLen */
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.engines.RSACoreEngine.getInputBlockSize:()I
            iconst_1
            iadd
            if_icmpne 4
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.forEncryption:Z
            ifne 4
         3: .line 96
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "input too large for RSA cipher."
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         4: .line 101
      StackMap locals:
      StackMap stack:
            iload 2 /* inOff */
            ifne 5
            iload 3 /* inLen */
            aload 1 /* in */
            arraylength
            if_icmpeq 8
         5: .line 103
      StackMap locals:
      StackMap stack:
            iload 3 /* inLen */
            newarray 8
            astore 4 /* block */
        start local 4 // byte[] block
         6: .line 105
            aload 1 /* in */
            iload 2 /* inOff */
            aload 4 /* block */
            iconst_0
            iload 3 /* inLen */
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         7: .line 106
            goto 9
        end local 4 // byte[] block
         8: .line 109
      StackMap locals:
      StackMap stack:
            aload 1 /* in */
            astore 4 /* block */
        start local 4 // byte[] block
         9: .line 112
      StackMap locals: byte[]
      StackMap stack:
            new java.math.BigInteger
            dup
            iconst_1
            aload 4 /* block */
            invokespecial java.math.BigInteger.<init>:(I[B)V
            astore 5 /* res */
        start local 5 // java.math.BigInteger res
        10: .line 113
            aload 5 /* res */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            invokevirtual org.bouncycastle.crypto.params.RSAKeyParameters.getModulus:()Ljava/math/BigInteger;
            invokevirtual java.math.BigInteger.compareTo:(Ljava/math/BigInteger;)I
            iflt 12
        11: .line 115
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "input too large for RSA cipher."
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
        12: .line 118
      StackMap locals: java.math.BigInteger
      StackMap stack:
            aload 5 /* res */
            areturn
        end local 5 // java.math.BigInteger res
        end local 4 // byte[] block
        end local 3 // int inLen
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0   13     0   this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;
            0   13     1     in  [B
            0   13     2  inOff  I
            0   13     3  inLen  I
            6    8     4  block  [B
            9   13     4  block  [B
           10   13     5    res  Ljava/math/BigInteger;
    MethodParameters:
       Name  Flags
      in     
      inOff  
      inLen  

  public byte[] convertOutput(java.math.BigInteger);
    descriptor: (Ljava/math/BigInteger;)[B
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=4, args_size=2
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
        start local 1 // java.math.BigInteger result
         0: .line 124
            aload 1 /* result */
            invokevirtual java.math.BigInteger.toByteArray:()[B
            astore 2 /* output */
        start local 2 // byte[] output
         1: .line 126
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.forEncryption:Z
            ifeq 10
         2: .line 128
            aload 2 /* output */
            iconst_0
            baload
            ifne 6
            aload 2 /* output */
            arraylength
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.engines.RSACoreEngine.getOutputBlockSize:()I
            if_icmple 6
         3: .line 130
            aload 2 /* output */
            arraylength
            iconst_1
            isub
            newarray 8
            astore 3 /* tmp */
        start local 3 // byte[] tmp
         4: .line 132
            aload 2 /* output */
            iconst_1
            aload 3 /* tmp */
            iconst_0
            aload 3 /* tmp */
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         5: .line 134
            aload 3 /* tmp */
            areturn
        end local 3 // byte[] tmp
         6: .line 137
      StackMap locals: byte[]
      StackMap stack:
            aload 2 /* output */
            arraylength
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.engines.RSACoreEngine.getOutputBlockSize:()I
            if_icmpge 14
         7: .line 139
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.engines.RSACoreEngine.getOutputBlockSize:()I
            newarray 8
            astore 3 /* tmp */
        start local 3 // byte[] tmp
         8: .line 141
            aload 2 /* output */
            iconst_0
            aload 3 /* tmp */
            aload 3 /* tmp */
            arraylength
            aload 2 /* output */
            arraylength
            isub
            aload 2 /* output */
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         9: .line 143
            aload 3 /* tmp */
            areturn
        end local 3 // byte[] tmp
        10: .line 148
      StackMap locals:
      StackMap stack:
            aload 2 /* output */
            iconst_0
            baload
            ifne 14
        11: .line 150
            aload 2 /* output */
            arraylength
            iconst_1
            isub
            newarray 8
            astore 3 /* tmp */
        start local 3 // byte[] tmp
        12: .line 152
            aload 2 /* output */
            iconst_1
            aload 3 /* tmp */
            iconst_0
            aload 3 /* tmp */
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        13: .line 154
            aload 3 /* tmp */
            areturn
        end local 3 // byte[] tmp
        14: .line 158
      StackMap locals:
      StackMap stack:
            aload 2 /* output */
            areturn
        end local 2 // byte[] output
        end local 1 // java.math.BigInteger result
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0   15     0    this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;
            0   15     1  result  Ljava/math/BigInteger;
            1   15     2  output  [B
            4    6     3     tmp  [B
            8   10     3     tmp  [B
           12   14     3     tmp  [B
    MethodParameters:
        Name  Flags
      result  

  public java.math.BigInteger processBlock(java.math.BigInteger);
    descriptor: (Ljava/math/BigInteger;)Ljava/math/BigInteger;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=12, args_size=2
        start local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
        start local 1 // java.math.BigInteger input
         0: .line 163
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            instanceof org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters
            ifeq 15
         1: .line 170
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            checkcast org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters
            astore 2 /* crtKey */
        start local 2 // org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters crtKey
         2: .line 172
            aload 2 /* crtKey */
            invokevirtual org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters.getP:()Ljava/math/BigInteger;
            astore 3 /* p */
        start local 3 // java.math.BigInteger p
         3: .line 173
            aload 2 /* crtKey */
            invokevirtual org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters.getQ:()Ljava/math/BigInteger;
            astore 4 /* q */
        start local 4 // java.math.BigInteger q
         4: .line 174
            aload 2 /* crtKey */
            invokevirtual org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters.getDP:()Ljava/math/BigInteger;
            astore 5 /* dP */
        start local 5 // java.math.BigInteger dP
         5: .line 175
            aload 2 /* crtKey */
            invokevirtual org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters.getDQ:()Ljava/math/BigInteger;
            astore 6 /* dQ */
        start local 6 // java.math.BigInteger dQ
         6: .line 176
            aload 2 /* crtKey */
            invokevirtual org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters.getQInv:()Ljava/math/BigInteger;
            astore 7 /* qInv */
        start local 7 // java.math.BigInteger qInv
         7: .line 181
            aload 1 /* input */
            aload 3 /* p */
            invokevirtual java.math.BigInteger.remainder:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            aload 5 /* dP */
            aload 3 /* p */
            invokevirtual java.math.BigInteger.modPow:(Ljava/math/BigInteger;Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 8 /* mP */
        start local 8 // java.math.BigInteger mP
         8: .line 184
            aload 1 /* input */
            aload 4 /* q */
            invokevirtual java.math.BigInteger.remainder:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            aload 6 /* dQ */
            aload 4 /* q */
            invokevirtual java.math.BigInteger.modPow:(Ljava/math/BigInteger;Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 9 /* mQ */
        start local 9 // java.math.BigInteger mQ
         9: .line 187
            aload 8 /* mP */
            aload 9 /* mQ */
            invokevirtual java.math.BigInteger.subtract:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 10 /* h */
        start local 10 // java.math.BigInteger h
        10: .line 188
            aload 10 /* h */
            aload 7 /* qInv */
            invokevirtual java.math.BigInteger.multiply:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 10 /* h */
        11: .line 189
            aload 10 /* h */
            aload 3 /* p */
            invokevirtual java.math.BigInteger.mod:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 10 /* h */
        12: .line 192
            aload 10 /* h */
            aload 4 /* q */
            invokevirtual java.math.BigInteger.multiply:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 11 /* m */
        start local 11 // java.math.BigInteger m
        13: .line 193
            aload 11 /* m */
            aload 9 /* mQ */
            invokevirtual java.math.BigInteger.add:(Ljava/math/BigInteger;)Ljava/math/BigInteger;
            astore 11 /* m */
        14: .line 195
            aload 11 /* m */
            areturn
        end local 11 // java.math.BigInteger m
        end local 10 // java.math.BigInteger h
        end local 9 // java.math.BigInteger mQ
        end local 8 // java.math.BigInteger mP
        end local 7 // java.math.BigInteger qInv
        end local 6 // java.math.BigInteger dQ
        end local 5 // java.math.BigInteger dP
        end local 4 // java.math.BigInteger q
        end local 3 // java.math.BigInteger p
        end local 2 // org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters crtKey
        15: .line 199
      StackMap locals:
      StackMap stack:
            aload 1 /* input */
        16: .line 200
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            invokevirtual org.bouncycastle.crypto.params.RSAKeyParameters.getExponent:()Ljava/math/BigInteger;
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RSACoreEngine.key:Lorg/bouncycastle/crypto/params/RSAKeyParameters;
            invokevirtual org.bouncycastle.crypto.params.RSAKeyParameters.getModulus:()Ljava/math/BigInteger;
        17: .line 199
            invokevirtual java.math.BigInteger.modPow:(Ljava/math/BigInteger;Ljava/math/BigInteger;)Ljava/math/BigInteger;
            areturn
        end local 1 // java.math.BigInteger input
        end local 0 // org.bouncycastle.crypto.engines.RSACoreEngine this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0   18     0    this  Lorg/bouncycastle/crypto/engines/RSACoreEngine;
            0   18     1   input  Ljava/math/BigInteger;
            2   15     2  crtKey  Lorg/bouncycastle/crypto/params/RSAPrivateCrtKeyParameters;
            3   15     3       p  Ljava/math/BigInteger;
            4   15     4       q  Ljava/math/BigInteger;
            5   15     5      dP  Ljava/math/BigInteger;
            6   15     6      dQ  Ljava/math/BigInteger;
            7   15     7    qInv  Ljava/math/BigInteger;
            8   15     8      mP  Ljava/math/BigInteger;
            9   15     9      mQ  Ljava/math/BigInteger;
           10   15    10       h  Ljava/math/BigInteger;
           13   15    11       m  Ljava/math/BigInteger;
    MethodParameters:
       Name  Flags
      input  
}
SourceFile: "RSACoreEngine.java"