Public Key

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A key that is used to encrypt a message and can be freely distributed.

Cryptography: The study of secret communication and its techniques, including encryption, decryption, and hashing.
Cryptanalysis: The study of breaking codes and ciphers without knowing the secret key, i.e., attacking cryptographic systems.
Symmetric Key Cryptography: A cryptographic system in which the same key is used for encryption and decryption.
Asymmetric Key Cryptography: A cryptographic system in which a public key is used for encryption and a private key is used for decryption.
RSA Algorithm: A public-key cryptosystem that is widely used for secure data transmission. It is based on the difficulty of factoring large integers.
Digital Signatures: A mathematical technique used to verify the authenticity and integrity of digital messages or documents.
Key Management: The process of securely storing, distributing, and revoking cryptographic keys.
SSL/TLS: A protocol that provides secure communication over the internet, typically used for web browsing and email.
Hash Functions: A mathematical function that converts a message into a fixed length output, used for data integrity and authentication.
Authentication: The process of verifying the identity of a user or system, commonly used in online transactions and access control.
RSA (Rivest-Shamir-Adleman): RSA is the most popular and widely used Public Key Cryptography algorithm. It was invented by Ron Rivest, Adi Shamir, and Leonard Adleman in 1978. RSA is based on the mathematical concept of factorization of large prime numbers, making it secure against most attacks.
Diffie-Hellman: Diffie-Hellman is a Public Key Cryptography algorithm that allows secure exchange of cryptographic keys between two parties. It was invented by Whitfield Diffie and Martin Hellman in 1976. Diffie-Hellman does not provide encryption on its own, but it allows the two parties to agree on a shared secret key that can be used for symmetric encryption.
ECC (Elliptic Curve Cryptography): ECC is a relatively new Public Key Cryptography algorithm that uses the mathematics of elliptic curves to generate keys. It has a shorter key length compared to other algorithms, making it efficient for smaller devices such as smartphones and smart cards.
DSA (Digital Signature Algorithm): DSA is a Public Key Cryptography algorithm used for digital signatures. It was invented by the National Security Agency (NSA) in the US. It is similar to the Diffie-Hellman algorithm but is used for authentication instead of encryption.
El Gamal: El Gamal is a Public Key Cryptography algorithm that is similar to the Diffie-Hellman algorithm. It was invented by Taher Elgamal in 1985. El Gamal is used for encryption and digital signatures.
GPG (GNU Privacy Guard): GPG is a free and open-source implementation of the OpenPGP standard for Public Key Cryptography. It uses a combination of different algorithms such as RSA, Diffie-Hellman, and ECC for encryption, digital signatures, and key management.
PGP (Pretty Good Privacy): PGP is a proprietary implementation of the OpenPGP standard for Public Key Cryptography. It was invented by Phil Zimmermann in 1991. PGP is used for email encryption and digital signatures.
AES (Advanced Encryption Standard): AES is a symmetric encryption algorithm that is widely used for data encryption. It was selected as the standard encryption algorithm by the National Institute of Standards and Technology (NIST) in 2001. AES is not a Public Key Cryptography algorithm but can be used in combination with Public Key Cryptography algorithms for secure communication.
"Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys."
"Each key pair consists of a public key and a corresponding private key."
"Key pairs are generated with cryptographic algorithms based on mathematical problems termed one-way functions."
"Security of public-key cryptography depends on keeping the private key secret."
"The public key can be openly distributed without compromising security."
"In a public-key encryption system, anyone with a public key can encrypt a message, yielding a ciphertext."
"Only those who know the corresponding private key can decrypt the ciphertext to obtain the original message."
"A journalist can publish the public key of an encryption key pair on a web site so that sources can send secret messages to the news organization in ciphertext."
"However, public-key encryption does not conceal metadata like what computer a source used to send a message, when they sent it, or how long it is."
"Public-key encryption on its own also does not tell the recipient anything about who sent a message—it just conceals the content of a message in a ciphertext."
"In a digital signature system, a sender can use a private key together with a message to create a signature."
"Anyone with the corresponding public key can verify whether the signature matches the message."
"a forger who does not know the private key cannot find any message/signature pair that will pass verification with the public key."
"A software publisher can create a signature key pair and include the public key in software installed on computers."
"Any computer receiving an update can confirm it is genuine by verifying the signature using the public key."
"They underpin numerous Internet standards, such as Transport Layer Security (TLS), SSH, S/MIME and PGP."
"including applications and protocols which offer assurance of the confidentiality, authenticity, and non-repudiability of electronic communications and data storage."
"Compared to symmetric encryption, asymmetric encryption is rather slower than good symmetric encryption, too slow for many purposes."
"Today's cryptosystems (such as TLS, Secure Shell) use both symmetric encryption and asymmetric encryption."
"often by using asymmetric encryption to securely exchange a secret key which is then used for symmetric encryption." By providing these quotes, you can easily refer back to the paragraph and approach each study question with the necessary information.