Introduction to security encryption

Catalog

  Symmetric encryption

Asymmetric encryption

certificate

Mixed encryption  

digital signature

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•   Symmetric encryption

AES The key length of is 128、192、256 There are three kinds of . In symmetric encryption algorithm , For the moment AES Is safe . But there is a problem , How to distribute the key ? Transmission in the Internet environment , Keys are easy to steal .     Generally speaking, there is 3 Key distribution methods ：    

1、 Private shared key    

2、 Key distribution center send    

3、 Asymmetric encryption   To encrypt   Symmetric encryption key  

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• Asymmetric encryption

The general asymmetric encryption algorithm uses RSA Algorithm Generate key pair （ Public key pub_key、 Private key pri_key） Public keys are generally public , The private key is saved by yourself , No one else knows Characteristic is ：    

1、 Public key encrypted plaintext information , Only the corresponding private key can be decrypted （ For typical asymmetric encryption ）    

2、 The plaintext information encrypted by the private key , Only the corresponding public key can be decrypted （ For digital signature , I'll tell you more about it later ）

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• certificate

1、 for instance ： I have a driver's license in my life , Id card , Diploma, etc , These are issued by the authority , It can be used as proof of legitimacy .

2、 The public key may be counterfeited , In the process of using asymmetric encryption , Transfer the public key , There is still a threat to the security of asymmetric encryption .

3、 To address this threat , An authority is required to issue a certificate on whether the public key is legal

4、 Generally, these institutions are internationally recognized , Or some companies need to pay for certificates

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• Mixed encryption  

 

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• digital signature

1、 Signatures in life , Such as signing a labor contract 、 Leave slip signed by the leader , The function is to show that it is operated by myself

2、 Empathy , Digital signatures on the Internet , It is the proof that the message was sent personally , Not forged or tampered with