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Keylogging Ontology

Encryption Key

An Encryption Key is a random set of keyboard characters generated specifically to encrypt and decrypt data. Encryption keys are created by algorithms or formulas that make each key unique and difficult to predict.

Scope: Endpoint Security, Malware
Mobile Trust uses AES (Advanced Encryption Standard) Encryption Keys to encrypt and decrypt data, wherein a Symmetric Key formula is involved. AES is based on Rijndael encryption and encryption keys.  See Related information: Rijndael Encryption


Symmetric Key Pair

Symmetric key encryption involves the use of a secret, mathematical key pair to encrypt and decrypt data. The keys are identical.

Symmetric encryption formulas are very efficient at processing large amounts of information and are computationally less intensive than asymmetric encryption algorithms. There are two types of symmetric encryption algorithms: Stream Ciphers and Block Ciphers.

Block Ciphers
Block Ciphers encrypt plaintext in fixed-size blocks of bits. For example a block cipher encryption algorithm might take a 128-bit block of plaintext as input, and output a pseudorandom 128-bit block to produce an encrypted message. The transformation is controlled using an Encryption Key. Decryption is similar: the decryption algorithm takes, in this example, a pseudorandom 128-bit block combined with the secret key, to reproduce the original 128-bit block of plaintext.

AES is a Block Cipher with a 128-bit block size.

Stream Ciphers
Stream Ciphers encrypt plaintext one byte or one bit at a time. A Stream Cipher can be thought of as a block cipher with the smallest possible block size. An encryption algorithm is used to combine plaintext bits with a pseudorandom bit stream (known as a Keystream) to produce an encrypted message.

Advantages/Disadvantages of Symmetric Key Encryption

Symmetric encryption algorithms are comparatively easy to use and fast. They are also very efficient in processing large amounts of information and involve less intensive computation than asymmetric encryption algorithms.

A major disadvantage of symmetric encryption algorithms is the requirement for a shared secret key to be exchanged between two parties: the sender and the recipient. The process of choosing, distributing and storing keys is difficult to achieve in a secure manner, and a high level of trust is required. Keys should be changed regularly and kept secure during distribution process known as Key Management.

Another disadvantage is that there is no provision for Data Origin Authentication and data integrity. The recipient can neither authenticate the sender nor verify that the decrypted message is the same as the original. For more information, see the Related Reference: Data Origin Authentication.

Figure 1. How Symmetric Key Encryption and Decryption Works »    How Symmetric Key Encryption and Decryption Works

Asymmetric (Public and Private) Key Pair

A Public and Private Key Pair is comprised of two unique mathematically related keys. The longer the key, the harder it is to break the encryption. The following is an example of a Public Key:

3055 4541 07B1 D673 18GA CF6E RT2D EFD6 FD37 89B9 E069 EA97 FC10 3W35 F576 AE31 W4FV C8E4 4802 7W86 ER8F KAFA 552F 122D F11B 2R67 C894 2651 C0EE 2781 E673 UA2B 4103 S236 E2WD WE02 0501 1201

The Public Key is accessible to everyone via a publicly available directory. As the name suggests, the Private Key is not accessible to anyone except its private owner. The key pair is related by a mathematical formula in such a way that whatever is encrypted with a Public Key can only be decrypted by its uniquely related Private Key and vice versa.

Advantages/Disadvantages of Asymmetric Key Encryption

Asymmetric encryption algorithms are comparatively safe because of the Private Key requirement.

A disadvantage of asymmetric encryption is that is comparatively slow because of longer key length and the complexity of its encryption algorithms. The length and complexity of the Public Key is required in order for it to be too difficult for an intruder to decrypt the public key, because it would reveal the Private Key.

Figure 2. How Asymmetric Key Encryption and Decryption Works »    How Symmetric Key Encryption and Decryption Works

Related Terminology: Summary Descriptions

Certificate Authority (CA)
A Certificate or Certification Authority (CA) is an entity that issues digital certificates. The certificate certifies the ownership of a public key by the certificate owner.

Digital Signature
A Digital Signature is an algorithm for authenticating a digital message or document. The term is analogous to a paper signature used to authenticate a paper document, however encryption key technology for authentication instead.

Public Key Infrastructure (PKI)
A PKI is an comprehensive system of software, hardware, people, policies, and procedures needed to create, implement, and revoke digital certificates. This infrastructure uses a Certificate Authority (CA) to bind a public key with a user identity.

SSL Certificate
An SSL Certificate, a type of digital certificate, is issued by a CA to certify that the link between a website and a user's browser has been secured using SSL (Secure Sockets Layer) encryption.

X.509 Certificate
An X.509 certificate binds an identity (user, subscriber, router, or automated message guard) to a public key value.

Related Information:
Keylogging Ontology
Problem & Solution
MobileTrust: FAQs
Rijndael Encryption

Related Concept:

Related Reference:
Data Origin Authentication