Security Mechanisms---notes for Android

First, security mainly solves what problem:

1, confidentiality 2, identification/Authentication 3, Integrity 4, non-repudiation

In everyday life, a cryptographic technique that can be thought of consciously

1, letter encryption 2, Tibetan head poem 3, to write 4, algorithm and secret key separation 5, any rule can define cryptography

Second, the security mechanism of symmetric encryption

1.

Algorithm: Permutation algorithm and turn array algorithm DES AES

Three, asymmetric encryption (public key cryptography) Overview

1. Asymmetric Encryption model

2. Public and private keys

3. The theoretical foundation of public key algorithm

4. RSA algorithm

RSA based on the difficulty of decomposing large numbers

Public/private key length at least 1024bit

Iv. secret key exchange of security mechanisms

1. Advantages and disadvantages of symmetric encryption

Efficient

Secret key exchange issues

RSA is not as secure as encryption, but when choosing 256bit AES is still capable of most security areas

2. Advantages and disadvantages of public key cryptography

A, the security is high enough

b, no secret key exchange issues

c, low efficiency, slow for big data encryption

Security Mechanisms---notes for Android