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.crypto.engines.VMPCEngine implements org.bouncycastle.crypto.StreamCipher
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.bouncycastle.crypto.engines.VMPCEngine
  super_class: java.lang.Object
{
  protected byte n;
    descriptor: B
    flags: (0x0004) ACC_PROTECTED

  protected byte[] P;
    descriptor: [B
    flags: (0x0004) ACC_PROTECTED

  protected byte s;
    descriptor: B
    flags: (0x0004) ACC_PROTECTED

  protected byte[] workingIV;
    descriptor: [B
    flags: (0x0004) ACC_PROTECTED

  protected byte[] workingKey;
    descriptor: [B
    flags: (0x0004) ACC_PROTECTED

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
         0: .line 9
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 15
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
         2: .line 16
            aload 0 /* this */
            aconst_null
            putfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
         3: .line 17
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
         4: .line 9
            return
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    5     0  this  Lorg/bouncycastle/crypto/engines/VMPCEngine;

  public java.lang.String getAlgorithmName();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
         0: .line 24
            ldc "VMPC"
            areturn
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/engines/VMPCEngine;

  public void init(boolean, org.bouncycastle.crypto.CipherParameters);
    descriptor: (ZLorg/bouncycastle/crypto/CipherParameters;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=5, args_size=3
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
        start local 1 // boolean forEncryption
        start local 2 // org.bouncycastle.crypto.CipherParameters params
         0: .line 39
            aload 2 /* params */
            instanceof org.bouncycastle.crypto.params.ParametersWithIV
            ifne 4
         1: .line 41
            new java.lang.IllegalArgumentException
            dup
         2: .line 42
            ldc "VMPC init parameters must include an IV"
         3: .line 41
            invokespecial java.lang.IllegalArgumentException.<init>:(Ljava/lang/String;)V
            athrow
         4: .line 45
      StackMap locals:
      StackMap stack:
            aload 2 /* params */
            checkcast org.bouncycastle.crypto.params.ParametersWithIV
            astore 3 /* ivParams */
        start local 3 // org.bouncycastle.crypto.params.ParametersWithIV ivParams
         5: .line 46
            aload 3 /* ivParams */
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getParameters:()Lorg/bouncycastle/crypto/CipherParameters;
            checkcast org.bouncycastle.crypto.params.KeyParameter
            astore 4 /* key */
        start local 4 // org.bouncycastle.crypto.params.KeyParameter key
         6: .line 48
            aload 3 /* ivParams */
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getParameters:()Lorg/bouncycastle/crypto/CipherParameters;
            instanceof org.bouncycastle.crypto.params.KeyParameter
            ifne 10
         7: .line 50
            new java.lang.IllegalArgumentException
            dup
         8: .line 51
            ldc "VMPC init parameters must include a key"
         9: .line 50
            invokespecial java.lang.IllegalArgumentException.<init>:(Ljava/lang/String;)V
            athrow
        10: .line 54
      StackMap locals: org.bouncycastle.crypto.params.ParametersWithIV org.bouncycastle.crypto.params.KeyParameter
      StackMap stack:
            aload 0 /* this */
            aload 3 /* ivParams */
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getIV:()[B
            putfield org.bouncycastle.crypto.engines.VMPCEngine.workingIV:[B
        11: .line 56
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingIV:[B
            ifnull 12
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingIV:[B
            arraylength
            iconst_1
            if_icmplt 12
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingIV:[B
            arraylength
            sipush 768
            if_icmple 13
        12: .line 58
      StackMap locals:
      StackMap stack:
            new java.lang.IllegalArgumentException
            dup
            ldc "VMPC requires 1 to 768 bytes of IV"
            invokespecial java.lang.IllegalArgumentException.<init>:(Ljava/lang/String;)V
            athrow
        13: .line 61
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 4 /* key */
            invokevirtual org.bouncycastle.crypto.params.KeyParameter.getKey:()[B
            putfield org.bouncycastle.crypto.engines.VMPCEngine.workingKey:[B
        14: .line 63
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingKey:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingIV:[B
            invokevirtual org.bouncycastle.crypto.engines.VMPCEngine.initKey:([B[B)V
        15: .line 64
            return
        end local 4 // org.bouncycastle.crypto.params.KeyParameter key
        end local 3 // org.bouncycastle.crypto.params.ParametersWithIV ivParams
        end local 2 // org.bouncycastle.crypto.CipherParameters params
        end local 1 // boolean forEncryption
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot           Name  Signature
            0   16     0           this  Lorg/bouncycastle/crypto/engines/VMPCEngine;
            0   16     1  forEncryption  Z
            0   16     2         params  Lorg/bouncycastle/crypto/CipherParameters;
            5   16     3       ivParams  Lorg/bouncycastle/crypto/params/ParametersWithIV;
            6   16     4            key  Lorg/bouncycastle/crypto/params/KeyParameter;
    MethodParameters:
               Name  Flags
      forEncryption  
      params         

  protected void initKey(byte[], byte[]);
    descriptor: ([B[B)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=6, locals=5, args_size=3
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
        start local 1 // byte[] keyBytes
        start local 2 // byte[] ivBytes
         0: .line 68
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
         1: .line 69
            aload 0 /* this */
            sipush 256
            newarray 8
            putfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
         2: .line 70
            iconst_0
            istore 3 /* i */
        start local 3 // int i
         3: goto 6
         4: .line 72
      StackMap locals: int
      StackMap stack:
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* i */
            iload 3 /* i */
            i2b
            bastore
         5: .line 70
            iinc 3 /* i */ 1
      StackMap locals:
      StackMap stack:
         6: iload 3 /* i */
            sipush 256
            if_icmplt 4
        end local 3 // int i
         7: .line 75
            iconst_0
            istore 3 /* m */
        start local 3 // int m
         8: goto 14
         9: .line 77
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* m */
            sipush 255
            iand
            baload
            iadd
            aload 1 /* keyBytes */
            iload 3 /* m */
            aload 1 /* keyBytes */
            arraylength
            irem
            baload
            iadd
            sipush 255
            iand
            baload
            putfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
        10: .line 78
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* m */
            sipush 255
            iand
            baload
            istore 4 /* temp */
        start local 4 // byte temp
        11: .line 79
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* m */
            sipush 255
            iand
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            baload
            bastore
        12: .line 80
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            iload 4 /* temp */
            bastore
        end local 4 // byte temp
        13: .line 75
            iinc 3 /* m */ 1
      StackMap locals:
      StackMap stack:
        14: iload 3 /* m */
            sipush 768
            if_icmplt 9
        end local 3 // int m
        15: .line 82
            iconst_0
            istore 3 /* m */
        start local 3 // int m
        16: goto 22
        17: .line 84
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* m */
            sipush 255
            iand
            baload
            iadd
            aload 2 /* ivBytes */
            iload 3 /* m */
            aload 2 /* ivBytes */
            arraylength
            irem
            baload
            iadd
            sipush 255
            iand
            baload
            putfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
        18: .line 85
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* m */
            sipush 255
            iand
            baload
            istore 4 /* temp */
        start local 4 // byte temp
        19: .line 86
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            iload 3 /* m */
            sipush 255
            iand
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            baload
            bastore
        20: .line 87
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            iload 4 /* temp */
            bastore
        end local 4 // byte temp
        21: .line 82
            iinc 3 /* m */ 1
      StackMap locals:
      StackMap stack:
        22: iload 3 /* m */
            sipush 768
            if_icmplt 17
        end local 3 // int m
        23: .line 89
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
        24: .line 90
            return
        end local 2 // byte[] ivBytes
        end local 1 // byte[] keyBytes
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0   25     0      this  Lorg/bouncycastle/crypto/engines/VMPCEngine;
            0   25     1  keyBytes  [B
            0   25     2   ivBytes  [B
            3    7     3         i  I
            8   15     3         m  I
           11   13     4      temp  B
           16   23     3         m  I
           19   21     4      temp  B
    MethodParameters:
          Name  Flags
      keyBytes  
      ivBytes   

  public void processBytes(byte[], int, int, byte[], int);
    descriptor: ([BII[BI)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=6, locals=9, args_size=6
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // int len
        start local 4 // byte[] out
        start local 5 // int outOff
         0: .line 95
            iload 2 /* inOff */
            iload 3 /* len */
            iadd
            aload 1 /* in */
            arraylength
            if_icmple 2
         1: .line 97
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "input buffer too short"
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         2: .line 100
      StackMap locals:
      StackMap stack:
            iload 5 /* outOff */
            iload 3 /* len */
            iadd
            aload 4 /* out */
            arraylength
            if_icmple 4
         3: .line 102
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "output buffer too short"
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         4: .line 105
      StackMap locals:
      StackMap stack:
            iconst_0
            istore 6 /* i */
        start local 6 // int i
         5: goto 14
         6: .line 107
      StackMap locals: int
      StackMap stack:
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            sipush 255
            iand
            baload
            iadd
            sipush 255
            iand
            baload
            putfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
         7: .line 108
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            baload
            sipush 255
            iand
            baload
            iconst_1
            iadd
            sipush 255
            iand
            baload
            istore 7 /* z */
        start local 7 // byte z
         8: .line 110
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            sipush 255
            iand
            baload
            istore 8 /* temp */
        start local 8 // byte temp
         9: .line 111
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            sipush 255
            iand
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            baload
            bastore
        10: .line 112
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            iload 8 /* temp */
            bastore
        11: .line 113
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            iconst_1
            iadd
            sipush 255
            iand
            i2b
            putfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
        12: .line 116
            aload 4 /* out */
            iload 6 /* i */
            iload 5 /* outOff */
            iadd
            aload 1 /* in */
            iload 6 /* i */
            iload 2 /* inOff */
            iadd
            baload
            iload 7 /* z */
            ixor
            i2b
            bastore
        end local 8 // byte temp
        end local 7 // byte z
        13: .line 105
            iinc 6 /* i */ 1
      StackMap locals:
      StackMap stack:
        14: iload 6 /* i */
            iload 3 /* len */
            if_icmplt 6
        end local 6 // int i
        15: .line 118
            return
        end local 5 // int outOff
        end local 4 // byte[] out
        end local 3 // int len
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0   16     0    this  Lorg/bouncycastle/crypto/engines/VMPCEngine;
            0   16     1      in  [B
            0   16     2   inOff  I
            0   16     3     len  I
            0   16     4     out  [B
            0   16     5  outOff  I
            5   15     6       i  I
            8   13     7       z  B
            9   13     8    temp  B
    MethodParameters:
        Name  Flags
      in      
      inOff   
      len     
      out     
      outOff  

  public void reset();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
         0: .line 122
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingKey:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.workingIV:[B
            invokevirtual org.bouncycastle.crypto.engines.VMPCEngine.initKey:([B[B)V
         1: .line 123
            return
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lorg/bouncycastle/crypto/engines/VMPCEngine;

  public byte returnByte(byte);
    descriptor: (B)B
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=6, locals=4, args_size=2
        start local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
        start local 1 // byte in
         0: .line 127
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            sipush 255
            iand
            baload
            iadd
            sipush 255
            iand
            baload
            putfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
         1: .line 128
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            baload
            sipush 255
            iand
            baload
            iconst_1
            iadd
            sipush 255
            iand
            baload
            istore 2 /* z */
        start local 2 // byte z
         2: .line 130
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            sipush 255
            iand
            baload
            istore 3 /* temp */
        start local 3 // byte temp
         3: .line 131
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            sipush 255
            iand
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            baload
            bastore
         4: .line 132
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.P:[B
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.s:B
            sipush 255
            iand
            iload 3 /* temp */
            bastore
         5: .line 133
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
            iconst_1
            iadd
            sipush 255
            iand
            i2b
            putfield org.bouncycastle.crypto.engines.VMPCEngine.n:B
         6: .line 136
            iload 1 /* in */
            iload 2 /* z */
            ixor
            i2b
            ireturn
        end local 3 // byte temp
        end local 2 // byte z
        end local 1 // byte in
        end local 0 // org.bouncycastle.crypto.engines.VMPCEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    7     0  this  Lorg/bouncycastle/crypto/engines/VMPCEngine;
            0    7     1    in  B
            2    7     2     z  B
            3    7     3  temp  B
    MethodParameters:
      Name  Flags
      in    
}
SourceFile: "VMPCEngine.java"