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.modes.CBCBlockCipher implements org.bouncycastle.crypto.BlockCipher
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.bouncycastle.crypto.modes.CBCBlockCipher
  super_class: java.lang.Object
{
  private byte[] IV;
    descriptor: [B
    flags: (0x0002) ACC_PRIVATE

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

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

  private int blockSize;
    descriptor: I
    flags: (0x0002) ACC_PRIVATE

  private org.bouncycastle.crypto.BlockCipher cipher;
    descriptor: Lorg/bouncycastle/crypto/BlockCipher;
    flags: (0x0002) ACC_PRIVATE

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

  public void <init>(org.bouncycastle.crypto.BlockCipher);
    descriptor: (Lorg/bouncycastle/crypto/BlockCipher;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
        start local 1 // org.bouncycastle.crypto.BlockCipher cipher
         0: .line 28
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 20
            aload 0 /* this */
            aconst_null
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
         2: .line 31
            aload 0 /* this */
            aload 1 /* cipher */
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
         3: .line 32
            aload 0 /* this */
            aload 1 /* cipher */
            invokeinterface org.bouncycastle.crypto.BlockCipher.getBlockSize:()I
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
         4: .line 34
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            newarray 8
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.IV:[B
         5: .line 35
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            newarray 8
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
         6: .line 36
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            newarray 8
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcNextV:[B
         7: .line 37
            return
        end local 1 // org.bouncycastle.crypto.BlockCipher cipher
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    8     0    this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;
            0    8     1  cipher  Lorg/bouncycastle/crypto/BlockCipher;
    MethodParameters:
        Name  Flags
      cipher  

  public org.bouncycastle.crypto.BlockCipher getUnderlyingCipher();
    descriptor: ()Lorg/bouncycastle/crypto/BlockCipher;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
         0: .line 46
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            areturn
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;

  public void init(boolean, org.bouncycastle.crypto.CipherParameters);
    descriptor: (ZLorg/bouncycastle/crypto/CipherParameters;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=5, args_size=3
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
        start local 1 // boolean encrypting
        start local 2 // org.bouncycastle.crypto.CipherParameters params
         0: .line 64
            aload 0 /* this */
            iload 1 /* encrypting */
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.encrypting:Z
         1: .line 66
            aload 2 /* params */
            instanceof org.bouncycastle.crypto.params.ParametersWithIV
            ifeq 10
         2: .line 68
            aload 2 /* params */
            checkcast org.bouncycastle.crypto.params.ParametersWithIV
            astore 3 /* ivParam */
        start local 3 // org.bouncycastle.crypto.params.ParametersWithIV ivParam
         3: .line 69
            aload 3 /* ivParam */
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getIV:()[B
            astore 4 /* iv */
        start local 4 // byte[] iv
         4: .line 71
            aload 4 /* iv */
            arraylength
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            if_icmpeq 6
         5: .line 73
            new java.lang.IllegalArgumentException
            dup
            ldc "initialisation vector must be the same length as block size"
            invokespecial java.lang.IllegalArgumentException.<init>:(Ljava/lang/String;)V
            athrow
         6: .line 76
      StackMap locals: org.bouncycastle.crypto.params.ParametersWithIV byte[]
      StackMap stack:
            aload 4 /* iv */
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.IV:[B
            iconst_0
            aload 4 /* iv */
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         7: .line 78
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.modes.CBCBlockCipher.reset:()V
         8: .line 80
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            iload 1 /* encrypting */
            aload 3 /* ivParam */
            invokevirtual org.bouncycastle.crypto.params.ParametersWithIV.getParameters:()Lorg/bouncycastle/crypto/CipherParameters;
            invokeinterface org.bouncycastle.crypto.BlockCipher.init:(ZLorg/bouncycastle/crypto/CipherParameters;)V
        end local 4 // byte[] iv
        end local 3 // org.bouncycastle.crypto.params.ParametersWithIV ivParam
         9: .line 81
            goto 12
        10: .line 84
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.modes.CBCBlockCipher.reset:()V
        11: .line 86
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            iload 1 /* encrypting */
            aload 2 /* params */
            invokeinterface org.bouncycastle.crypto.BlockCipher.init:(ZLorg/bouncycastle/crypto/CipherParameters;)V
        12: .line 88
      StackMap locals:
      StackMap stack:
            return
        end local 2 // org.bouncycastle.crypto.CipherParameters params
        end local 1 // boolean encrypting
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0   13     0        this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;
            0   13     1  encrypting  Z
            0   13     2      params  Lorg/bouncycastle/crypto/CipherParameters;
            3    9     3     ivParam  Lorg/bouncycastle/crypto/params/ParametersWithIV;
            4    9     4          iv  [B
    Exceptions:
      throws java.lang.IllegalArgumentException
    MethodParameters:
            Name  Flags
      encrypting  
      params      

  public java.lang.String getAlgorithmName();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
         0: .line 97
            new java.lang.StringBuilder
            dup
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            invokeinterface org.bouncycastle.crypto.BlockCipher.getAlgorithmName:()Ljava/lang/String;
            invokestatic java.lang.String.valueOf:(Ljava/lang/Object;)Ljava/lang/String;
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            ldc "/CBC"
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            areturn
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;

  public int getBlockSize();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
         0: .line 107
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            invokeinterface org.bouncycastle.crypto.BlockCipher.getBlockSize:()I
            ireturn
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;

  public int processBlock(byte[], int, byte[], int);
    descriptor: ([BI[BI)I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=5, args_size=5
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // byte[] out
        start local 4 // int outOff
         0: .line 130
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.encrypting:Z
            ifeq 1
            aload 0 /* this */
            aload 1 /* in */
            iload 2 /* inOff */
            aload 3 /* out */
            iload 4 /* outOff */
            invokevirtual org.bouncycastle.crypto.modes.CBCBlockCipher.encryptBlock:([BI[BI)I
            goto 2
      StackMap locals:
      StackMap stack:
         1: aload 0 /* this */
            aload 1 /* in */
            iload 2 /* inOff */
            aload 3 /* out */
            iload 4 /* outOff */
            invokevirtual org.bouncycastle.crypto.modes.CBCBlockCipher.decryptBlock:([BI[BI)I
      StackMap locals:
      StackMap stack: int
         2: ireturn
        end local 4 // int outOff
        end local 3 // byte[] out
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    3     0    this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;
            0    3     1      in  [B
            0    3     2   inOff  I
            0    3     3     out  [B
            0    3     4  outOff  I
    Exceptions:
      throws org.bouncycastle.crypto.DataLengthException, java.lang.IllegalStateException
    MethodParameters:
        Name  Flags
      in      
      inOff   
      out     
      outOff  

  public void reset();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
         0: .line 139
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.IV:[B
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.IV:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         1: .line 140
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcNextV:[B
            iconst_0
            invokestatic org.bouncycastle.util.Arrays.fill:([BB)V
         2: .line 142
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            invokeinterface org.bouncycastle.crypto.BlockCipher.reset:()V
         3: .line 143
            return
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    4     0  this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;

  private int encryptBlock(byte[], int, byte[], int);
    descriptor: ([BI[BI)I
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=6, locals=6, args_size=5
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // byte[] out
        start local 4 // int outOff
         0: .line 164
            iload 2 /* inOff */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            iadd
            aload 1 /* in */
            arraylength
            if_icmple 2
         1: .line 166
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "input buffer too short"
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         2: .line 173
      StackMap locals:
      StackMap stack:
            iconst_0
            istore 5 /* i */
        start local 5 // int i
         3: goto 6
         4: .line 175
      StackMap locals: int
      StackMap stack:
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            iload 5 /* i */
            dup2
            baload
            aload 1 /* in */
            iload 2 /* inOff */
            iload 5 /* i */
            iadd
            baload
            ixor
            i2b
            bastore
         5: .line 173
            iinc 5 /* i */ 1
      StackMap locals:
      StackMap stack:
         6: iload 5 /* i */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            if_icmplt 4
        end local 5 // int i
         7: .line 178
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            iconst_0
            aload 3 /* out */
            iload 4 /* outOff */
            invokeinterface org.bouncycastle.crypto.BlockCipher.processBlock:([BI[BI)I
            istore 5 /* length */
        start local 5 // int length
         8: .line 183
            aload 3 /* out */
            iload 4 /* outOff */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         9: .line 185
            iload 5 /* length */
            ireturn
        end local 5 // int length
        end local 4 // int outOff
        end local 3 // byte[] out
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0   10     0    this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;
            0   10     1      in  [B
            0   10     2   inOff  I
            0   10     3     out  [B
            0   10     4  outOff  I
            3    7     5       i  I
            8   10     5  length  I
    Exceptions:
      throws org.bouncycastle.crypto.DataLengthException, java.lang.IllegalStateException
    MethodParameters:
        Name  Flags
      in      
      inOff   
      out     
      outOff  

  private int decryptBlock(byte[], int, byte[], int);
    descriptor: ([BI[BI)I
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=5, locals=7, args_size=5
        start local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // byte[] out
        start local 4 // int outOff
         0: .line 207
            iload 2 /* inOff */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            iadd
            aload 1 /* in */
            arraylength
            if_icmple 2
         1: .line 209
            new org.bouncycastle.crypto.DataLengthException
            dup
            ldc "input buffer too short"
            invokespecial org.bouncycastle.crypto.DataLengthException.<init>:(Ljava/lang/String;)V
            athrow
         2: .line 212
      StackMap locals:
      StackMap stack:
            aload 1 /* in */
            iload 2 /* inOff */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcNextV:[B
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         3: .line 214
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cipher:Lorg/bouncycastle/crypto/BlockCipher;
            aload 1 /* in */
            iload 2 /* inOff */
            aload 3 /* out */
            iload 4 /* outOff */
            invokeinterface org.bouncycastle.crypto.BlockCipher.processBlock:([BI[BI)I
            istore 5 /* length */
        start local 5 // int length
         4: .line 219
            iconst_0
            istore 6 /* i */
        start local 6 // int i
         5: goto 8
         6: .line 221
      StackMap locals: int int
      StackMap stack:
            aload 3 /* out */
            iload 4 /* outOff */
            iload 6 /* i */
            iadd
            dup2
            baload
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            iload 6 /* i */
            baload
            ixor
            i2b
            bastore
         7: .line 219
            iinc 6 /* i */ 1
      StackMap locals:
      StackMap stack:
         8: iload 6 /* i */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.blockSize:I
            if_icmplt 6
        end local 6 // int i
         9: .line 229
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
            astore 6 /* tmp */
        start local 6 // byte[] tmp
        10: .line 230
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcNextV:[B
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcV:[B
        11: .line 231
            aload 0 /* this */
            aload 6 /* tmp */
            putfield org.bouncycastle.crypto.modes.CBCBlockCipher.cbcNextV:[B
        12: .line 233
            iload 5 /* length */
            ireturn
        end local 6 // byte[] tmp
        end local 5 // int length
        end local 4 // int outOff
        end local 3 // byte[] out
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.modes.CBCBlockCipher this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0   13     0    this  Lorg/bouncycastle/crypto/modes/CBCBlockCipher;
            0   13     1      in  [B
            0   13     2   inOff  I
            0   13     3     out  [B
            0   13     4  outOff  I
            4   13     5  length  I
            5    9     6       i  I
           10   13     6     tmp  [B
    Exceptions:
      throws org.bouncycastle.crypto.DataLengthException, java.lang.IllegalStateException
    MethodParameters:
        Name  Flags
      in      
      inOff   
      out     
      outOff  
}
SourceFile: "CBCBlockCipher.java"