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.RFC3394WrapEngine implements org.bouncycastle.crypto.Wrapper
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.bouncycastle.crypto.engines.RFC3394WrapEngine
  super_class: java.lang.Object
{
  private org.bouncycastle.crypto.BlockCipher engine;
    descriptor: Lorg/bouncycastle/crypto/BlockCipher;
    flags: (0x0002) ACC_PRIVATE

  private org.bouncycastle.crypto.params.KeyParameter param;
    descriptor: Lorg/bouncycastle/crypto/params/KeyParameter;
    flags: (0x0002) ACC_PRIVATE

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

  private byte[] iv;
    descriptor: [B
    flags: (0x0002) ACC_PRIVATE

  public void <init>(org.bouncycastle.crypto.BlockCipher);
    descriptor: (Lorg/bouncycastle/crypto/BlockCipher;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=2, args_size=2
        start local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
        start local 1 // org.bouncycastle.crypto.BlockCipher engine
         0: .line 31
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 27
            aload 0 /* this */
            bipush 8
            newarray 8
            dup
            iconst_0
         2: .line 28
            bipush -90
            bastore
            dup
            iconst_1
            bipush -90
            bastore
            dup
            iconst_2
            bipush -90
            bastore
            dup
            iconst_3
            bipush -90
            bastore
            dup
            iconst_4
         3: .line 29
            bipush -90
            bastore
            dup
            iconst_5
            bipush -90
            bastore
            dup
            bipush 6
            bipush -90
            bastore
            dup
            bipush 7
            bipush -90
            bastore
            putfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
         4: .line 33
            aload 0 /* this */
            aload 1 /* engine */
            putfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.engine:Lorg/bouncycastle/crypto/BlockCipher;
         5: .line 34
            return
        end local 1 // org.bouncycastle.crypto.BlockCipher engine
        end local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    6     0    this  Lorg/bouncycastle/crypto/engines/RFC3394WrapEngine;
            0    6     1  engine  Lorg/bouncycastle/crypto/BlockCipher;
    MethodParameters:
        Name  Flags
      engine  

  public void init(boolean, org.bouncycastle.crypto.CipherParameters);
    descriptor: (ZLorg/bouncycastle/crypto/CipherParameters;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=3
        start local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
        start local 1 // boolean forWrapping
        start local 2 // org.bouncycastle.crypto.CipherParameters param
         0: .line 40
            aload 0 /* this */
            iload 1 /* forWrapping */
            putfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.forWrapping:Z
         1: .line 42
            aload 2 /* param */
            instanceof org.bouncycastle.crypto.params.ParametersWithRandom
            ifeq 3
         2: .line 44
            aload 2 /* param */
            checkcast org.bouncycastle.crypto.params.ParametersWithRandom
            invokevirtual org.bouncycastle.crypto.params.ParametersWithRandom.getParameters:()Lorg/bouncycastle/crypto/CipherParameters;
            astore 2 /* param */
         3: .line 47
      StackMap locals:
      StackMap stack:
            aload 2 /* param */
            instanceof org.bouncycastle.crypto.params.KeyParameter
            ifeq 6
         4: .line 49
            aload 0 /* this */
            aload 2 /* param */
            checkcast org.bouncycastle.crypto.params.KeyParameter
            putfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.param:Lorg/bouncycastle/crypto/params/KeyParameter;
         5: .line 50
            goto 11
         6: .line 51
      StackMap locals:
      StackMap stack:
            aload 2 /* param */
            instanceof org.bouncycastle.crypto.params.ParametersWithIV
            ifeq 11
         7: .line 53
            aload 0 /* this */
            aload 2 /* param */
            checkcast org.bouncycastle.crypto.params.ParametersWithIV
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getIV:()[B
            putfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
         8: .line 54
            aload 0 /* this */
            aload 2 /* param */
            checkcast org.bouncycastle.crypto.params.ParametersWithIV
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getParameters:()Lorg/bouncycastle/crypto/CipherParameters;
            checkcast org.bouncycastle.crypto.params.KeyParameter
            putfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.param:Lorg/bouncycastle/crypto/params/KeyParameter;
         9: .line 55
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            bipush 8
            if_icmpeq 11
        10: .line 57
            new java.lang.IllegalArgumentException
            dup
            ldc "IV not equal to 8"
            invokespecial java.lang.IllegalArgumentException.<init>:(Ljava/lang/String;)V
            athrow
        11: .line 60
      StackMap locals:
      StackMap stack:
            return
        end local 2 // org.bouncycastle.crypto.CipherParameters param
        end local 1 // boolean forWrapping
        end local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0   12     0         this  Lorg/bouncycastle/crypto/engines/RFC3394WrapEngine;
            0   12     1  forWrapping  Z
            0   12     2        param  Lorg/bouncycastle/crypto/CipherParameters;
    MethodParameters:
             Name  Flags
      forWrapping  
      param        

  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.RFC3394WrapEngine this
         0: .line 64
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.engine:Lorg/bouncycastle/crypto/BlockCipher;
            invokeinterface org.bouncycastle.crypto.BlockCipher.getAlgorithmName:()Ljava/lang/String;
            areturn
        end local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/engines/RFC3394WrapEngine;

  public byte[] wrap(byte[], int, int);
    descriptor: ([BII)[B
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=12, args_size=4
        start local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // int inLen
         0: .line 72
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.forWrapping:Z
            ifne 2
         1: .line 74
            new java.lang.IllegalStateException
            dup
            ldc "not set for wrapping"
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
         2: .line 77
      StackMap locals:
      StackMap stack:
            iload 3 /* inLen */
            bipush 8
            idiv
            istore 4 /* n */
        start local 4 // int n
         3: .line 79
            iload 4 /* n */
            bipush 8
            imul
            iload 3 /* inLen */
            if_icmpeq 5
         4: .line 81
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "wrap data must be a multiple of 8 bytes"
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         5: .line 84
      StackMap locals: int
      StackMap stack:
            iload 3 /* inLen */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            iadd
            newarray 8
            astore 5 /* block */
        start local 5 // byte[] block
         6: .line 85
            bipush 8
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            iadd
            newarray 8
            astore 6 /* buf */
        start local 6 // byte[] buf
         7: .line 87
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            iconst_0
            aload 5 /* block */
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         8: .line 88
            aload 1 /* in */
            iconst_0
            aload 5 /* block */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            iload 3 /* inLen */
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         9: .line 90
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.engine:Lorg/bouncycastle/crypto/BlockCipher;
            iconst_1
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.param:Lorg/bouncycastle/crypto/params/KeyParameter;
            invokeinterface org.bouncycastle.crypto.BlockCipher.init:(ZLorg/bouncycastle/crypto/CipherParameters;)V
        10: .line 92
            iconst_0
            istore 7 /* j */
        start local 7 // int j
        11: goto 30
        12: .line 94
      StackMap locals: byte[] byte[] int
      StackMap stack:
            iconst_1
            istore 8 /* i */
        start local 8 // int i
        13: goto 28
        14: .line 96
      StackMap locals: int
      StackMap stack:
            aload 5 /* block */
            iconst_0
            aload 6 /* buf */
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        15: .line 97
            aload 5 /* block */
            bipush 8
            iload 8 /* i */
            imul
            aload 6 /* buf */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            bipush 8
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        16: .line 98
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.engine:Lorg/bouncycastle/crypto/BlockCipher;
            aload 6 /* buf */
            iconst_0
            aload 6 /* buf */
            iconst_0
            invokeinterface org.bouncycastle.crypto.BlockCipher.processBlock:([BI[BI)I
            pop
        17: .line 100
            iload 4 /* n */
            iload 7 /* j */
            imul
            iload 8 /* i */
            iadd
            istore 9 /* t */
        start local 9 // int t
        18: .line 101
            iconst_1
            istore 10 /* k */
        start local 10 // int k
        19: goto 24
        20: .line 103
      StackMap locals: int int
      StackMap stack:
            iload 9 /* t */
            i2b
            istore 11 /* v */
        start local 11 // byte v
        21: .line 105
            aload 6 /* buf */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            iload 10 /* k */
            isub
            dup2
            baload
            iload 11 /* v */
            ixor
            i2b
            bastore
        22: .line 107
            iload 9 /* t */
            bipush 8
            iushr
            istore 9 /* t */
        end local 11 // byte v
        23: .line 101
            iinc 10 /* k */ 1
      StackMap locals:
      StackMap stack:
        24: iload 9 /* t */
            ifne 20
        end local 10 // int k
        25: .line 110
            aload 6 /* buf */
            iconst_0
            aload 5 /* block */
            iconst_0
            bipush 8
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        26: .line 111
            aload 6 /* buf */
            bipush 8
            aload 5 /* block */
            bipush 8
            iload 8 /* i */
            imul
            bipush 8
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        end local 9 // int t
        27: .line 94
            iinc 8 /* i */ 1
      StackMap locals:
      StackMap stack:
        28: iload 8 /* i */
            iload 4 /* n */
            if_icmple 14
        end local 8 // int i
        29: .line 92
            iinc 7 /* j */ 1
      StackMap locals:
      StackMap stack:
        30: iload 7 /* j */
            bipush 6
            if_icmpne 12
        end local 7 // int j
        31: .line 115
            aload 5 /* block */
            areturn
        end local 6 // byte[] buf
        end local 5 // byte[] block
        end local 4 // int n
        end local 3 // int inLen
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0   32     0   this  Lorg/bouncycastle/crypto/engines/RFC3394WrapEngine;
            0   32     1     in  [B
            0   32     2  inOff  I
            0   32     3  inLen  I
            3   32     4      n  I
            6   32     5  block  [B
            7   32     6    buf  [B
           11   31     7      j  I
           13   29     8      i  I
           18   27     9      t  I
           19   25    10      k  I
           21   23    11      v  B
    MethodParameters:
       Name  Flags
      in     
      inOff  
      inLen  

  public byte[] unwrap(byte[], int, int);
    descriptor: ([BII)[B
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=6, locals=13, args_size=4
        start local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // int inLen
         0: .line 124
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.forWrapping:Z
            ifeq 2
         1: .line 126
            new java.lang.IllegalStateException
            dup
            ldc "not set for unwrapping"
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
         2: .line 129
      StackMap locals:
      StackMap stack:
            iload 3 /* inLen */
            bipush 8
            idiv
            istore 4 /* n */
        start local 4 // int n
         3: .line 131
            iload 4 /* n */
            bipush 8
            imul
            iload 3 /* inLen */
            if_icmpeq 5
         4: .line 133
            new org.bouncycastle.crypto.InvalidCipherTextException
            dup
            ldc "unwrap data must be a multiple of 8 bytes"
            invokespecial org.bouncycastle.crypto.InvalidCipherTextException.<init>:(Ljava/lang/String;)V
            athrow
         5: .line 136
      StackMap locals: int
      StackMap stack:
            iload 3 /* inLen */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            isub
            newarray 8
            astore 5 /* block */
        start local 5 // byte[] block
         6: .line 137
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            newarray 8
            astore 6 /* a */
        start local 6 // byte[] a
         7: .line 138
            bipush 8
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            iadd
            newarray 8
            astore 7 /* buf */
        start local 7 // byte[] buf
         8: .line 140
            aload 1 /* in */
            iconst_0
            aload 6 /* a */
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         9: .line 141
            aload 1 /* in */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            aload 5 /* block */
            iconst_0
            iload 3 /* inLen */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            isub
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        10: .line 143
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.engine:Lorg/bouncycastle/crypto/BlockCipher;
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.param:Lorg/bouncycastle/crypto/params/KeyParameter;
            invokeinterface org.bouncycastle.crypto.BlockCipher.init:(ZLorg/bouncycastle/crypto/CipherParameters;)V
        11: .line 145
            iinc 4 /* n */ -1
        12: .line 147
            iconst_5
            istore 8 /* j */
        start local 8 // int j
        13: goto 32
        14: .line 149
      StackMap locals: org.bouncycastle.crypto.engines.RFC3394WrapEngine byte[] int int int byte[] byte[] byte[] int
      StackMap stack:
            iload 4 /* n */
            istore 9 /* i */
        start local 9 // int i
        15: goto 30
        16: .line 151
      StackMap locals: int
      StackMap stack:
            aload 6 /* a */
            iconst_0
            aload 7 /* buf */
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        17: .line 152
            aload 5 /* block */
            bipush 8
            iload 9 /* i */
            iconst_1
            isub
            imul
            aload 7 /* buf */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            bipush 8
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        18: .line 154
            iload 4 /* n */
            iload 8 /* j */
            imul
            iload 9 /* i */
            iadd
            istore 10 /* t */
        start local 10 // int t
        19: .line 155
            iconst_1
            istore 11 /* k */
        start local 11 // int k
        20: goto 25
        21: .line 157
      StackMap locals: int int
      StackMap stack:
            iload 10 /* t */
            i2b
            istore 12 /* v */
        start local 12 // byte v
        22: .line 159
            aload 7 /* buf */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            arraylength
            iload 11 /* k */
            isub
            dup2
            baload
            iload 12 /* v */
            ixor
            i2b
            bastore
        23: .line 161
            iload 10 /* t */
            bipush 8
            iushr
            istore 10 /* t */
        end local 12 // byte v
        24: .line 155
            iinc 11 /* k */ 1
      StackMap locals:
      StackMap stack:
        25: iload 10 /* t */
            ifne 21
        end local 11 // int k
        26: .line 164
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.engine:Lorg/bouncycastle/crypto/BlockCipher;
            aload 7 /* buf */
            iconst_0
            aload 7 /* buf */
            iconst_0
            invokeinterface org.bouncycastle.crypto.BlockCipher.processBlock:([BI[BI)I
            pop
        27: .line 165
            aload 7 /* buf */
            iconst_0
            aload 6 /* a */
            iconst_0
            bipush 8
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        28: .line 166
            aload 7 /* buf */
            bipush 8
            aload 5 /* block */
            bipush 8
            iload 9 /* i */
            iconst_1
            isub
            imul
            bipush 8
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
        end local 10 // int t
        29: .line 149
            iinc 9 /* i */ -1
      StackMap locals:
      StackMap stack:
        30: iload 9 /* i */
            iconst_1
            if_icmpge 16
        end local 9 // int i
        31: .line 147
            iinc 8 /* j */ -1
      StackMap locals:
      StackMap stack:
        32: iload 8 /* j */
            ifge 14
        end local 8 // int j
        33: .line 170
            aload 6 /* a */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.engines.RFC3394WrapEngine.iv:[B
            invokestatic org.bouncycastle.util.Arrays.constantTimeAreEqual:([B[B)Z
            ifne 35
        34: .line 172
            new org.bouncycastle.crypto.InvalidCipherTextException
            dup
            ldc "checksum failed"
            invokespecial org.bouncycastle.crypto.InvalidCipherTextException.<init>:(Ljava/lang/String;)V
            athrow
        35: .line 175
      StackMap locals:
      StackMap stack:
            aload 5 /* block */
            areturn
        end local 7 // byte[] buf
        end local 6 // byte[] a
        end local 5 // byte[] block
        end local 4 // int n
        end local 3 // int inLen
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.engines.RFC3394WrapEngine this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0   36     0   this  Lorg/bouncycastle/crypto/engines/RFC3394WrapEngine;
            0   36     1     in  [B
            0   36     2  inOff  I
            0   36     3  inLen  I
            3   36     4      n  I
            6   36     5  block  [B
            7   36     6      a  [B
            8   36     7    buf  [B
           13   33     8      j  I
           15   31     9      i  I
           19   29    10      t  I
           20   26    11      k  I
           22   24    12      v  B
    Exceptions:
      throws org.bouncycastle.crypto.InvalidCipherTextException
    MethodParameters:
       Name  Flags
      in     
      inOff  
      inLen  
}
SourceFile: "RFC3394WrapEngine.java"