Shulou(Shulou.com)06/01 Report--

Cryptographic algorithms and protocols:

Symmetric encryption: The encryption and decryption parties use the same key.

Public key encryption: encryption and decryption using different keys, keys are divided into public key and private key, appear in pairs of public key hidden in the private key.

One-way encryption: Also known as data integrity algorithm, extracts the signature of the data, and compares the second extraction with the word to verify data integrity.

Authentication Protocol: Verify the authenticity of certain communicating entities based on certain algorithms.

Symmetric encryption:

Specific algorithm:

DES algorithm, 3DES algorithm, TDEA algorithm, Blowfish algorithm, RC5 algorithm, IDEA algorithm.

Features:

Advantages: open algorithm, small amount of calculation, encryption speed, encryption efficiency.

Disadvantages: Poor security, requiring a unique key for each use, making key maintenance difficult.

Public key encryption: (asymmetric encryption)

Specific algorithm:

RSA, ElGamal, knapsack algorithm, Rabin(Rabin's encryption method can be said to be a special case of RSA method), public key encryption algorithm in Diffie-Hellman (D-H) key exchange protocol, Elliptic Curve Cryptography (ECC).

Specific explanation:

Public key refers to a pair of encryption key and decryption key, these two keys are mathematically related, with a user key encryption information, only with the user's decryption key can be decrypted. If you know one, you can't compute the other. Thus, if one of the keys is disclosed, the secrecy of the other is not compromised. The public key is called the public key; the secret key is called the private key.

If the encryption key is public, this is used by the client to upload encrypted data to the private key owner, which is referred to as public key encryption (narrow sense). For example, encrypted data sent by customers of Internet banking to account operations on the bank's website.

If the decryption key is public, information encrypted with the private key can be decrypted with the public key, which is used by the client to verify that the data or file published by the party holding the private key is complete and accurate, and the receiver thus knows that the information really came from someone who owns the private key. This is called a digital signature, and the public key is a digital certificate. For example, installers downloaded from the Internet typically carry a digital signature from the creator of the program, which proves that the program was indeed distributed by the author (company) and not forged by a third party and has not been tampered with (identity authentication/verification).

Examples of secure data transfer processes:

One of the problems in this model is how to ensure that Bran's public key used by Arya is a reliable public key, and the solution is to publish it through a reliable authority, namely CA.

Digital Certificate Certification Center:

Certificate Authority is abbreviated as CA. CA is an entity trusted by both parties in PKI system, which is called Trusted Third Party (TTP). CA refers to the organization that issues, manages and abolishes digital certificates. CA's role is to check the legitimacy of the certificate holder's identity, and issue certificates (sign certificates) to prevent certificates from being forged or tampered with, and to manage certificates and keys.

Examples of processes to verify data reliability with CA:

CA certificate format:

The common format for CA certificates is X509.

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