# Terminology

The following terminology is commonly used in cryptography and public key infrastructure (PKI).

Term | Description |
---|---|

Encryption |
The process of transforming data by using a cryptographic algorithm and key. The transformed data can be recovered only by using the same algorithm and the same (symmetric) or related (public) key. |

Decryption |
The process of returning encrypted data to its original form. |

Plaintext |
Originally referred to an unencrypted text message. Currently refers to any unencrypted data. |

Ciphertext |
Originally referred to an encrypted, and therefore unreadable, text message. Currently refers to any encrypted data. |

Hashing |
The process of converting variable length data into a fixed length, typically smaller, value. By comparing hashes, you can obtain reasonable assurance that two or more data are the same. |

Signature |
Encrypted hash of digital data typically used to authenticate the sender of the data or verify that the data was not tampered with during transmission. |

Algorithm |
A step-by-step procedure for encrypting data. |

Key |
A random or pseudorandom number used as input to a cryptographic algorithm to encrypt and decrypt data. |

Symmetric Key Cryptography |
Cryptography in which encryption and decryption use the same key. This is also known as secret key cryptography. |

Asymmetric Key Cryptography |
Cryptography in which encryption and decryption use a different but mathematically related key. This is also called public key cryptography. |

Encoding |
The process of encoding digital messages, including certificates, for transport across a network. |

Algorithm Provider |
A DLL that implements a cryptographic algorithm. |

Key Storage Provider |
A container for storing key material. Currently, keys can be stored in software, smart cards, or the trusted platform module (TPM). |

X.509 Certificate |
A digital document, typically issued by a certification authority, to verify the identity of an individual, system, or entity to other interested parties. |

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