Cryptography

Hybrid cryptosystem

In cryptography, a hybrid cryptosystem is one which combines the convenience of a public-key cryptosystem with the efficiency of a symmetric-key cryptosystem. Public-key cryptosystems are convenient in that they do not require the sender and receiver to share a common secret in order to communicate securely. However, they often rely on complicated mathematical computations and are thus generally much more inefficient than comparable symmetric-key cryptosystems. In many applications, the high cost of encrypting long messages in a public-key cryptosystem can be prohibitive. This is addressed by hybrid systems by using a combination of both. A hybrid cryptosystem can be constructed using any two separate cryptosystems: * a key encapsulation mechanism, which is a public-key cryptosystem, and * a data encapsulation scheme, which is a symmetric-key cryptosystem. The hybrid cryptosystem is itself a public-key system, whose public and private keys are the same as in the key encapsulation scheme. Note that for very long messages the bulk of the work in encryption/decryption is done by the more efficient symmetric-key scheme, while the inefficient public-key scheme is used only to encrypt/decrypt a short key value. All practical implementations of public key cryptography today employ the use of a hybrid system. Examples include the TLS protocol and the SSH protocol, that use a public-key mechanism for key exchange (such as Diffie-Hellman) and a symmetric-key mechanism for data encapsulation (such as AES). The OpenPGP file format and the PKCS #7 file format are other examples. Hybrid Public Key Encryption (HPKE, published as RFC 9180) is a modern standard for generic hybrid encryption. HPKE is used within multiple IETF protocols, including MLS and TLS Encrypted Hello. Envelope encryption is an example of a usage of hybrid cryptosystems in cloud computing. In a cloud context, hybrid cryptosystems also enable centralized key management. (Wikipedia).

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Other Public Key Cryptosystems: Part 1

Fundamental concepts of Diffie-Hellman Key exchange are discussed. ElGamal Cryptosystem is presented. Elliptic curves are Analyzed.

From playlist Network Security

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Other Public Key Cryptosystems: Part 2

Fundamental concepts of Diffie-Hellman Key exchange are discussed. ElGamal Cryptosystem is presented. Elliptic curves are Analyzed.

From playlist Network Security

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This video is part of an online course, Applied Cryptography. Check out the course here: https://www.udacity.com/course/cs387.

From playlist Applied Cryptography

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From playlist Cryptography

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Nexus Trimester - Delaram Kahrobaei (City University of New York)

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From playlist Nexus Trimester - 2016 - Secrecy and Privacy Theme

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!!Con West 2019 - Pranshu Bajpai: The Conjuring: ransomware edition!!

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From playlist 2022 Graduate Summer School on Post-quantum and Quantum Cryptography

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From playlist Seminar on Applied Geometry and Algebra (SIAM SAGA)

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From playlist Applied Cryptography

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From playlist SIAM Conference Videos

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From playlist Applied Cryptography

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Don’t forget to subscribe! This project series will teach you how to create your own cryptocurrency in C++. Throughout this course we will learn how to fork a crypto project, renaming things in the project, creating our very own genesis block, and changing parameters and values. In the en

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From playlist Number Theory

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From playlist Cryptography

Related pages

Key management | Shared secret | Ciphertext | OpenPGP | PKCS | Key encapsulation mechanism | Messaging Layer Security | Cryptography | Advanced Encryption Standard