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| Image courtesy of Stuart Miles at FreeDigitalPhotos.net |
In my effort to increase security awareness and obtain a cultural acceptance, I wanted to bring a focus on the importance of utilizing the science of cryptography to secure your data and communication channels with the implementation of encryption techniques.
The main focus for this post is to provide the reader with an understanding of the basic science behind cryptography. To do this, we will look at a fairly simple encryption algorithm called the Substitution Cipher, to see how it can be applied against a basic clear text messages to produce a ciphertext for secrecy. To decrypt the message, the recipient will need to have the algorithm, as well as the associated key.
In the days before microcomputers, messages were passed in written form, such as ink on a scroll, and carried by a soldier on a horse for delivery to the intended recipient. In these days, specific methods were put in place to protect the confidentiality of the message by manipulating the placement of the words to make it appear as nonsense to an individual who may intercept the message maliciously or unintentionally. However, for the intended recipient, the method could be reversed to allow the message to be interpreted, as long as the algorithm and key were shared.
These methods are knows as the science of cryptography, which is the art of secret writing with the implementation of an algorithm and key to a message to make it difficult, if not impossible, to view the original information. In addition, it is called encrypting and decrypting the message.
To illustrate, let's begin with the Substitution Cipher. This algorithm applies a key to shift the original letters of the message a number of spaces to the right. The number associated with how many shifts to the right is the "key" within the algorithm. For example, a "Rot 3" (Rotate 3) would have you shift the first letter of our cleartext message below, which is M, three spaces to the right, which would be P.
By utilizing the image below, we will begin with what is known as the plaintext, or original message, and apply the algorithm against it to produce a ciphertext. The algorithm we will use is the Substitution Cipher with the Rot 5 key and the plaintext I have chosen is:
MEET ME AT FOUR PM ON ELM STREET TODAY
To encrypt the plaintext, thus making it a ciphertext, simply start with the first letter of the message, which is M. Since we are using the Rot 5 algorithm, find M in the top portion of the grid where the alphabet is written in the shaded gray area. Once you have found M, select the number directly below it, which is R, to make your first letter of your encrypted ciphertext. Once you have completed the entire message, your encrypted ciphertext will look as follows:
RJJYRJFYKTZWURTSJQRXYWJJYYTIFD
As you can see, if this message was received with out understanding what encryption algorithm was applied, it would be difficult to decipher. For example, let's say you were aware that the Substitution Cipher was used, but did not know which key, such as Rot 3, 4, or 5. In this case, it would take a little time to decrypt the ciphertext back to cleartext. This value of knowing which Rot # was used is called the key. The use of the Substitution Cipher is the algorithm and knowing how many letters to shift (Rot 5) is the key. By applying all of this together, you can encrypt and decrypt your message, thus applying a layer of protection, for the confidentiality of the message the soldier is carrying on the horse, along it's path to the intended recipient.
Encryption algorithms have come a long way since the days of the scroll and delivery by horse. With that in mind, I am sure glad my computer does all of this encrypting/decrypting for me!!! Aren't you?!
Thank you for reading! Until next time, remember that you don't have to become a victim of a threat to become aware of a threat!
The main focus for this post is to provide the reader with an understanding of the basic science behind cryptography. To do this, we will look at a fairly simple encryption algorithm called the Substitution Cipher, to see how it can be applied against a basic clear text messages to produce a ciphertext for secrecy. To decrypt the message, the recipient will need to have the algorithm, as well as the associated key.
In the days before microcomputers, messages were passed in written form, such as ink on a scroll, and carried by a soldier on a horse for delivery to the intended recipient. In these days, specific methods were put in place to protect the confidentiality of the message by manipulating the placement of the words to make it appear as nonsense to an individual who may intercept the message maliciously or unintentionally. However, for the intended recipient, the method could be reversed to allow the message to be interpreted, as long as the algorithm and key were shared.
These methods are knows as the science of cryptography, which is the art of secret writing with the implementation of an algorithm and key to a message to make it difficult, if not impossible, to view the original information. In addition, it is called encrypting and decrypting the message.
To illustrate, let's begin with the Substitution Cipher. This algorithm applies a key to shift the original letters of the message a number of spaces to the right. The number associated with how many shifts to the right is the "key" within the algorithm. For example, a "Rot 3" (Rotate 3) would have you shift the first letter of our cleartext message below, which is M, three spaces to the right, which would be P.
By utilizing the image below, we will begin with what is known as the plaintext, or original message, and apply the algorithm against it to produce a ciphertext. The algorithm we will use is the Substitution Cipher with the Rot 5 key and the plaintext I have chosen is:
MEET ME AT FOUR PM ON ELM STREET TODAY
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| Image Produced by Troy Bevans |
To encrypt the plaintext, thus making it a ciphertext, simply start with the first letter of the message, which is M. Since we are using the Rot 5 algorithm, find M in the top portion of the grid where the alphabet is written in the shaded gray area. Once you have found M, select the number directly below it, which is R, to make your first letter of your encrypted ciphertext. Once you have completed the entire message, your encrypted ciphertext will look as follows:
RJJYRJFYKTZWURTSJQRXYWJJYYTIFD
As you can see, if this message was received with out understanding what encryption algorithm was applied, it would be difficult to decipher. For example, let's say you were aware that the Substitution Cipher was used, but did not know which key, such as Rot 3, 4, or 5. In this case, it would take a little time to decrypt the ciphertext back to cleartext. This value of knowing which Rot # was used is called the key. The use of the Substitution Cipher is the algorithm and knowing how many letters to shift (Rot 5) is the key. By applying all of this together, you can encrypt and decrypt your message, thus applying a layer of protection, for the confidentiality of the message the soldier is carrying on the horse, along it's path to the intended recipient.
Encryption algorithms have come a long way since the days of the scroll and delivery by horse. With that in mind, I am sure glad my computer does all of this encrypting/decrypting for me!!! Aren't you?!
Thank you for reading! Until next time, remember that you don't have to become a victim of a threat to become aware of a threat!
Thank you for the article.
ReplyDeleteAs we all can see, cybercrime became more spreader by day. Data security developers’ next challenge is to renew methods of data encryption in order to restrict cybercriminals from stealing important information. The same situation is observed in ideals virtual data room services for business.