Encryption

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Encryption
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What is Encryption?

• Encryption is the process of converting plain
  text into cipher text, with the goal of making
  the text unreadable

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Three Types of Encryption

• Symmetric or single Key
• Asymmetric or two key
• Hash or No key

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Symmetric Encryption

• Uses a single key to both encrypt and decrypt the
  text.

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Symmetric Encryption

• Symmetric cryptography is sometimes called
  "secret-key cryptography

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How Symmetric Encryption Works

• In symmetric key encryption, two people first
  agree on a pass phrase (or password).
• The encryption software then converts that pass
  phrase into a binary number.
• The software then uses that number (key) to
  encrypt all outgoing messages.
• The mathematical code for encrypting the message
  is called an algorithm.

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Asymmetric Encryption

• Overcomes the shortfalls of symmetric encryption
  by using two keys a public and a private key
• Used by (CA) Certificate Authority The CA issues
  an encrypted digital certificate containing the
  applicant's public key and a variety of other
  identification information.

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Asymmetric Encryption

• a public key is known to everyone and a private
  or secret key known only to the recipient of the
  message.

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Hash Functions

• One way functions because they perform one way
  transformation of the information that is
  irreversible

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Hash Functions

• Take a block of data as input, and produce a hash
  or message digest as output.

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Comparison of Symmetric and Asymmetric

• Symmetric encryption is faster.
• One disadvantage in symmetric encryption is that
  both the sender and the recipient must have an
  access to (same) encryption key.
• The key can be distributed personally, for
  instance, in a diskette, or it can be delivered
  encrypted (asymmetric encryption) or it can be
  distributed in some other secure way.

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Using a combination

• A combination of both Symmetric and Asymmetric
  can be used for optimum performance.

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Hash Functions

• Because asymmetric cryptographic algorithms are
  slow and can only encrypt blocks smaller than
  their key size, when computing digital
  signatures, it is interesting to sign a
  cryptographically strong message digest instead
  of the whole message

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Digital Certificate
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Digital Certificate

• An attachment to an electronic message used for
  security purposes. The most common use of a
  digital certificate is to verify that a user
  sending a message is who he or she claims to be,
  and to provide the receiver with the means to
  encode a reply.

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Process

• An individual wishing to send an encrypted
  message applies for a digital certificate from a
  Certificate Authority (CA). The CA issues an
  encrypted digital certificate containing the
  applicant's public key and a variety of other
  identification information. The CA makes its own
  public key readily available through print
  publicity or perhaps on the Internet.

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Certificate Authority

• The recipient of an encrypted message uses the
  CA's public key to decode the digital certificate
  attached to the message, verifies it as issued by
  the CA and then obtains the sender's public key
  and identification information held within the
  certificate. With this information, the recipient
  can send an encrypted reply.

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Thank You