cryptography
- what is it?
- where is it used?
- is it safe?
(black?)
In simplest terms, it is secret writing.
(show a encoded message)
By shifting the alphabet by one or more characters,
(show alphabet overlay, shift a second alphabet layer, include math symbols +1, 2)
the key is created,
(math symbols form a key)
and the secret text, or cipher, can be decoded.
(rewrite message as decoded)
the difficulty increases as the key becomes more complicated through simple and complex math operations.
(show math, *2, show how message would change)
(show math, /3, show how message changes)
the method of decoding becomes only possible if both parties hold the same key.
(math form a key, sent to other user, message also sent, decode)
To further complicate the process and keep information secure, a different key can be used to encrypt as well as decrypt. (symmetric and asymmetric key algorithms)
(show example, math > key, encrypt message)
(show example, key > math, decrypt message)
all of this is used in everyday life, such as:
- Pin numbers
- E-mail passwords
- mobile phones
- passwords
- SSL
- Smart cards
- DVD’s
and web applications
(pics… how? just show? illustrated?)
The function of encryption is to insure:
authentication, non-repudiation, confidentiality and integrity.
(
Authentication
Using a cryptographic system, we can establish the identity of a remote user (or system). A typical example is the SSL certificate of a web server providing proof to the user that he or she is connected to the correct server. The identity is not of the user, but of the cryptographic key of the user. Having a less secure key lowers the trust we can place on the identity.
Non-Repudiation
The concept of non-repudiation is particularly important for financial or e-commerce applications. Often, cryptographic tools are required to prove that a unique user has made a transaction request. It must not be possible for the user to refute his or her actions.
For example, a customer may request a transfer of money from her account to be paid to another account. Later, she claims never to have made the request and demands the money be refunded to the account. If we have non-repudiation through cryptography, we can prove – usually through digitally signing the transaction request, that the user authorized the transaction.
Confidentiality
More commonly, the biggest concern will be to keep information private. Cryptographic systems were originally developed to function in this capacity. Whether it be passwords sent during a log on process, or storing confidential medical records in a database, encryption can assure that only users who have access to the appropriate key will get access to the data.
Integrity
We can use cryptography to provide a means to ensure data is not viewed or altered during storage or transmission. Cryptographic hashes for example, can safeguard data by providing a secure checksum.
All electronic encryption is based on prime numbers,
(prime numbers pop up)
when multiplying two prime numbers,
(leave 2)
the result will create a product that is divisible by 1, itself, and the two prime numbers
(math, divide.)
to create a key which can be applied to an algorithm
(show key, show ‘algorithm’)
the message is further broken down into binary values (or code) and passed through the algorithm to create the encoded message.
(show word, binary, encoded message)
when using single digit primaries, the resulting code is an 8-bit encryption.
In 16 bit encryption 2 digits are used and so on…
(show 1 * 8 = 8-bit, 2*8 = 16bit, keep going?)
within 8-bit encryption, there is 256 possible keys 2^8
16-bit, 2^16, 2 digits, which has 65536 possible keys…
40-bit – 5 digits – 1.1 trillion keys
56-bit – 7 digits – 72 quadrillion
128-bit – 16 digits – 340,282,366,920,938,463,463,374,607,431,768,211,456 or 10^38 * 3.4
(show math, 8bit > 2^8 > 256 possibilities, etc 340,282,366,920,938,463,463,374,607,431,768,211,456)
With the encoded binary message, the message is then converted back into corresponding ASCII characters that are in fact the encrypted text which was sent around
(binary > ascii)
to decrypt the message without a key, the binary of this message is reversed through an algorithm and the possible keys.
(start applying the binary to keys and show result)
the result creates combinations of letters, with only one possible answer.
(highlight answer)
40-bit encryptions can be broken within 1 second
56 within 19 hours
64 estimated within 6.9 months
128 estimated within 105-125 years
(some kind of visual that refers back to the chart earlier)
Until recently 56 bit encryption was the standard, but has been replaced by 128-bit encryption after the 56 bit encryption method was cracked during a competition setup to test it’s integrity with a cash prize of $10,000
This doesn’t mean that a encryption method it can’t be broken.
Regardless of how complex it may seem,
Villains with the right information can easily take advantage of it.
Steal your information, steal your identity.
Protect your passwords.