需要掌握的内容如下:
- Two simple hash functions
- Hash functions based on cipher block chaining
- SHA(Secure hash algorithms)
Condenses压缩 arbitrary message to fixed size: h=H(M)
Good hash function 特征
- Evenly distributed
- Apparently random
Object: data integrity 数据完整性
--Used to detect changes to message
- One-way property
----Computationally 计算上 infeasible不可行的to find data mapping to specific hash
- Collsion-free property
----Computationally infeasible to find two data to same hash
Hash应用在哪些方面?
- Message authentication
- Digital signature 数字签名