hcrypto.engines
Class SubstitutionEngine

java.lang.Object
  hcrypto.cipher.CipherEngine
      hcrypto.cipher.BlockCipher
          hcrypto.engines.SubstitutionEngine

public class SubstitutionEngine
extends BlockCipher

Implements a keyword-based Substitution cipher algorithm for any range of alphabets, including az, AZ, azAZ, azAZ09, printable characters, all ASCII, and any of the Unicode character sets. A plaintext alphabet is retrieved from the SubstitutionKey class and stored in a character array. A cipher alphabet is created by inserting the characters from the keyword into the first elements of the array, followed by all remaining characters in the particular alphabet.

Encryption involves replacing a plaintext character from a given message with a character from the cipher alphabet with the same index. Decrypting works in the reverse order.

      plainKey = [a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,......];
      keyword = calm;
      cipherAlphabet = [c,a,l,m,b,d,e,f,g,h,i,j,k,n,o,p,......];
      
      engineEncrypt("cab") == "lca"
      engineDecrypt("lca") == "cab"
 

See also:

SubstitutionKey
Alphabet

Constructor Summary

SubstitutionEngine()
Creates a SubstitutionEngine and sets the alphabetRangeOptions instance variable to "111111", which translates to all six alphabet options.

Method Summary

java.lang.String	engineDecode(java.lang.String s) Returns an encoded String for the specified String.
java.lang.String	engineEncode(java.lang.String s) Returns an encoded String for the specified String.

Methods inherited from class hcrypto.cipher.CipherEngine

getAlphabetRangeOptions

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SubstitutionEngine

public SubstitutionEngine()

Creates a SubstitutionEngine and sets the alphabetRangeOptions instance variable to "111111", which translates to all six alphabet options.

Method Detail

engineEncode

public java.lang.String engineEncode(java.lang.String s)
                              throws java.lang.Exception

Returns an encoded String for the specified String. Characters which are not part of the chosen alphabet set are ignored.

Parameters:

s - the String to be encrypted

Throws:

java.lang.Exception

engineDecode

public java.lang.String engineDecode(java.lang.String s)
                              throws java.lang.Exception

Returns an encoded String for the specified String. Characters which are not part of the chosen alphabet set are ignored.

Parameters:

s - the String to be decrypted

Throws:

java.lang.Exception