# Security Concepts

Following is a list of general security concepts and their associated definitions that you need to know.

Concept Name | Definition
Authentication | The recipient of an authenticated message can be certain of the message's origin (its sender). Authentication reduces the possibility that another person has impersonated the sender of the message.
Authorization | The set of privileges available to an authenticated entity.
Certificate | A certificate is created when an entity's public key is signed by a trusted identity: a certificate authority. The certificate ensures that the entity's information is correct and that the public key actually belongs to that entity.
Certificate Authority | An application that creates public key certificates.
Confidentiality | A function of cryptography. Confidentiality guarantees that only the intended recipient(s) of a message can view the message (decrypt the ciphertext).
Cryptography | The act of writing and deciphering secret code resulting in secure messages.
Decryption | The process of converting the contents of an encrypted message (ciphertext) back into its original readable format (plaintext).
Digital Signature | A digital signature is created when a public key algorithm is used to sign the sender's message with the sender's private key. The digital signature assures that the document is authentic, has not been forged by another entity, has not been altered, and cannot be repudiated by the sender.
Encryption | The process of disguising the contents of a message and rendering it unreadable (ciphertext) to anyone but the intended recipient.
Identity | A user who is typically certified.
Integrity | The guarantee that the contents of the message received were not altered from the contents of the original message sent.
Non-repudiation | Undeniable proof of the origin, delivery, submission, or transmission of a message.
Public-Key Encryption | The process where the sender of a message encrypts the message with the public key of the recipient. Upon delivery, the message is decrypted by the recipient using the recipient's private key.
Public/Private Key Pair | A mathematically related set of two numbers where one is called the private key and the other is called the public key. Public keys are typically made widely available, while a private key is available only to the owner. Data encrypted with a public key can only be decrypted with its corresponding private key and vice versa. However, data encrypted with a public key cannot be decrypted with the same public key.
Trusted Certificate | A trusted certificate is a third party identity that is qualified with a level of trust. The trusted certificate is used when an identity is being validated as the entity it claims to be. The certificate authorities you trust are the issuers of trusted certificates.
Wallet | A wallet is an abstraction used to store and manage security credentials for an individual entity. It implements the storage and retrieval of credentials for use with various cryptographic services. A wallet resource locator (WRL) provides all the necessary information to locate the wallet.
Wallet Resource Locator | A directory path that provides all the necessary information to locate a particular wallet.
WRL | See Wallet Resource Locator.
X.509 | The public keys can be signed in various data formats. The X.509 format from ISO is one such popular format.