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With public-key encryption, only one key is needed to encrypt a message; the other is used for decrypting the message. A sender with a recipient’s public-key can thus encrypt a message which only the recipient can decrypt using his private key.

## How public key cryptography can be used in message and user authentication?

Using the public key algorithms, a message encrypted with one key can be decrypted only with the other. The two possible keys gives us two possible ways of sending messages. Encrypt with the private key, decrypt with the public, or encrypt with the public key, decrypt with the private.

## How is authentication achieved in cryptography?

The user is authenticated by sending to the authentication server his/her username together with a randomly challenge message that is encrypted by the secret key. Whereby, the user is considered as authenticated user if the server can match the received encrypted message using its share secret key.

## How does PGP achieve confidentiality and authentication in email?

PGP provides authentication through the use of Digital Signature. It provides confidentiality through the use of symmetric block encryption. It provides compression by using the ZIP algorithm, and EMAIL compatibility using the radix-64 encoding scheme.

Bob wants to send Alice an encrypted email. To do this, Bob takes Alice’s public key and encrypts his message to her. Then, when Alice receives the message, she takes the private key that is known only to her in order to decrypt the message from Bob.

## What is public key and private key with example?

Private Key and Public Key: The Differences

Private Key | Public Key |
---|---|

Remains in the confidential use of two individuals. | Available to everyone through the publicly accessible directory. |

The possibility of key getting lost, which will render the system void. | Key is publicly held so no possibility of loss. |

## What are the roles of the public and private key in cryptography?

In Public key, two keys are used one key is used for encryption and another key is used for decryption. One key (public key) is used for encrypt the plain text to convert it into cipher text and another key (private key) is used by receiver to decrypt the cipher text to read the message.

## How do you achieve confidentiality in cryptography?

When the goal is to achieve confidentiality, a recipient’s public key is used to encrypt messages. On receiving the message, the recipient is able to decrypt the message using his or her pri-vate key. In an asymmetric key cryptosystem, a public key cannot be used to derive the private key.

## What is confidentiality in cryptography?

Confidentiality. Confidentiality is most commonly addressed goal. The meaning of a message is concealed by encoding it. The sender encrypts the message using a cryptographic key. The recipient decrypts the message using a cryptographic key that may or may not be the same as the one used by the sender.

## How can cryptography protect confidentiality of information?

Cryptography ensures the integrity of data using hashing algorithms and message digests. By providing codes and digital keys to ensure that what is received is genuine and from the intended sender, the receiver is assured that the data received has not been tampered with during transmission.

## How do you achieve authentication and confidentiality in asymmetric encryption?

Asymmetric cryptography has two primary use cases: authentication and confidentiality. Using asymmetric cryptography, messages can be signed with a private key, and then anyone with the public key is able to verify that the message was created by someone possessing the corresponding private key.

## How PGP can achieve the confidentiality?

For confidentiality, PGP encrypts messages with an efficient single-key or conventional encryption algorithm known as IDEA. It then uses RSA to encrypt, with the receiver’s public key, the IDEA key used to encrypt the message. The receiver can use RSA to recover the IDEA key and use that key to recover the message.

## What do you mean by confidentiality and authentication concept in cryptography?

Confidentiality: First, cryptography protects the confidentiality (or secrecy) of information. … Authentication: Finally, cryptography can be used for authentication (and non-repudiation) services through digital signatures, digital certificates, or a Public Key Infrastructure (PKI).

The public key is used to encrypt data. The private key however is private. It is stored on user’s device and is used to decrypt data. … Being related in this case means that whatever is encrypted by the public key can only be decrypted by the related private key.

Each communicating pair of people need to share a key. … Alice obtains his public key, encrypts a message using this key and then sends it to Bob. Bob is then able to decrypt the message using the secret part of his own key.

## What is the key using for message confidentiality?

Applications. The most obvious application of a public key encryption system is for encrypting communication to provide confidentiality – a message that a sender encrypts using the recipient’s public key which can be decrypted only by the recipient’s paired private key.