Encryption and decryption of Linux

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• Security mechanisms: encryption/decryption, digital signature, access control, data integrity, authentication switching, flow control, routing control
  
  

• Key: Controls the instructions for encrypting and decrypting processes

• Algorithm: A set of rules that specify encryption and decryption

• Encryption, decryption: That is, the key through the specified algorithm to do a series of operations

• Therefore, the security of encryption and decryption is not nearly dependent on the encryption algorithm, the key security is even more important
  
  

• • symmetric encryption: Both sides use the same encryption method to encrypt and decrypt the same key

    • Advantages: encryption, decryption speed block

    • Cons:

      • It is difficult for the two parties to securely transfer the key to each other during the first communication

      • because no two users need to have a corresponding key, so the key is too many, difficult to manage

      • does not provide integrity authentication, so it is difficult to verify the identity of the sender and receiver

    • common algorithms: DES (Basic No), 3DES, AES, Blowfish, Twofish, Ieda, RC6, CAST5

  • Asymmetric encryption (public key cryptography): Decryption and decryption are performed separately using key pairs

    • Encrypt with public key, must decrypt with corresponding private key, encrypt with private key, must decrypt with corresponding public key

    • private key: for personal use only;

    • cons: Long key, long time

    • commonly used for: digital signatures , key exchange, and identity authentication

    • Common algorithms: RSA, DSA (for digital signatures), ELGamal
      
      

  • One-way encryption: Encryption by calculating the signature of a piece of data

    • Features: fixed length output regardless of original data size
      Irreversible: Unable to use the resulting data to reverse the decryption
      Avalanche effect: Small changes that lead to dramatic changes in results

    • For: Verifying the integrity of data

    • Common algorithms: MD5, SHA1, SHA256, SHA384, SHA512, CRC32
      

A key is an instruction that controls the process of encrypting and decrypting. The algorithm is a set of rules that specify how to encrypt and decrypt. Therefore, security is not only dependent on the encryption algorithm itself, the security of key management is more important

This article is from the "Ops Dog" blog, make sure to keep this source http://yunweigou.blog.51cto.com/6299641/1637108

Encryption and decryption of Linux