by Jonathan Roach (6 Submissions)
Category: Encryption
Compatability: Visual Basic 3.0
Difficulty: Beginner
Date Added: Wed 3rd February 2021
Rating: 
(11 Votes)
Explains the basic technique used to achieve data encryption and get you on your way to understanding Cryptography in general.
VBcoders
xmlns="http://www.w3.org/TR/REC-html40">
mso-bidi-font-family:"Times New Roman"'>Cryptography Primer
my primer article on cryptography!
"Times New Roman"'>cryp-tog-ra-phy (krip-taw-graph-e)
"Times New Roman"'>The process or skill of communicating in or deciphering
"Times New Roman"'>secret writings or ciphers.
"Times New Roman"'>
mso-bidi-font-family:"Times New Roman"'>Introduction
espionage, fraud, and theft of personal information.
the reasons for concealing, masking, shadowing
information in order to minimize the chance of that
revealed to potentially dangerous or mischievous
it's not that big of a deal, maybe you just want
you send email to your friends or something.
achieve the above is referred to as "Cryptography",
aimed at giving you a basic look into the world of
providing you with Visual Basic source code to get
way.
mso-bidi-font-family:"Times New Roman"'>What does Cryptography do?
mso-bidi-font-family:"Times New Roman"'>
conceals or hides data in order to make it un-readable to
it is used to secure documents and data by mixing
original data into mumbo jumbo basically.
example of encryption, lets say you want to send an
friend, and you don't want anyone else to see the true
going to send, because... it's top secret of course.
message would look something like this:
encryption handbook."
perform an encryption routine on the message before
and the result would look something like this:
"Times New Roman"'>?©§† ˆ³ß?|“œ?©§†"
the original text is all scrambled and basically not of any
it appears...
encrypted mail off to Frank, if Frank is unaware of
will probably mail you back and say something along
"What the heck is this stuff you sent me?".
sent it off to your good buddy Frank and he is
encryption/decryption software that you are, and he is
code/key needed to reverse your scrambled message all
view your message, while any others who may have
the way could not, or at least had a heck of a time
it, Cryptography scrambles/transforms data.
mso-bidi-font-family:"Times New Roman"'>Cryptography Overview
mso-bidi-font-family:"Times New Roman"'>
requires an encryption algorithm and a key; in it's basic form
this article I will not go into great detail on the many
encryption and key methods in use today but I will provide
foundation for encryption/decryption.
algorithm is simply the engine or code that handles all of
transform the original text (plaintext) into encoded text
performs mathematical and/or logical operations on the
transform it into the ciphertext and vice versa.
implies is just that, it is the key (code) that allows the
encrypt/decrypt data.
mso-bidi-font-family:"Times New Roman"'>Common Cryptography Algorithms
mso-bidi-font-family:"Times New Roman"'>
different algorithms for encrypting/decrypting data in use
today, some of them are very complex and others are
however they all serve the same purpose.
listing on some of the different cryptography algorithms;
Data Encryption Standard
encoded 3 times
and Adleman
scientists of the former Soviet Union
of PGP (Pretty Good Privacy)
but the above should be a starting point for you
info on the net.
mso-bidi-font-family:"Times New Roman"'>The One-Time Pad
mso-bidi-font-family:"Times New Roman"'>
one of the simplest encryption algorithms, it involves
which is the same length as the plaintext and then using
plaintext via the key, the math could be multiplication
(XOR) for example;
String
String
Integer
String
String
"CovertText"
"password42"
& plainText
Len(plainText)
keyChar)
& cipherText
""
Len(cipherText)
keyChar)
original: “ & plainText
""
code and paste it into a new project, then add a
in its click event put a call to the Crypt() sub.
Command1_Click()
click the button to see it in action.
with the above encryption algorithm though, first
encrypt something that is large in size the key size
large.
wanted to encrypt a string that is 50 characters in
would also have to be 50 characters in length,
our good friend Frank to have to enter a 50 character
simple message.
overcome with our next topic, which deals with
problem by using a repeating key.
mso-bidi-font-family:"Times New Roman"'>Repeating Key Algorithm - Viginere
Cipher
mso-bidi-font-family:"Times New Roman"'>
encryption algorithm deals with a key that repeats during
encryption/decryption process, for example the algorithm above
character algorithm, it performs math operations
the plaintext and key until the length of the key
reached - because the key and plaintext are the same
repeating key, our key can be any length we choose
the key is reached in our algorithm we simple start
of the key until our plaintext encryption is completed.
example, if our plaintext is "I have top secret codes"
"Pass"; obviously the key is shorter than our plaintext.
loop to encrypt our plaintext and this is how it looks:
key
char = P
The key just repeats until the length of the plaintext
method is much more practical and flexible for key names
algorithm that uses a repeating key.
"pw201"
"Top-Secret Message from Roach"
""
" & plainText, 0, "Before Encryption"
Len(plainText)
keyChar)
KeyIndex = 1
Encryption: " & cipherText, 0, "Original:" & plainText
paste this into a new project and call the Crypt()
click event to try it out. To reverse the encryption
encrypted text back through the counter loop in place of
sticking with me through this brief article on the subject,
gained a little knowledge about encryption from this.
that you shall become an encryption expert or
methods described in this article are bomb proof,
proof... whatever, I merely wanted to share the
the subject.