string - 为字符串生成校验和

Question

我想为字符串/数据生成校验和

1. The same data should produce the same Checksum
2. Two different data strings can't product same checksum. Random collision of 0.1% can be negligible
3. No encryption/decryption of data 
4. Checksum length need not be too huge and contains letters and characters.
5. Must be too fast and efficient. Imagine generating checksum(s) for 100 Mb of text data should be in less than 5mins. Generating 1000 checksums for less than 1 KB of each segment data should be in less than 10 seconds.

非常感谢任何算法或实现引用和建议。

Answer 1

您可以编写自定义哈希函数:(c++)

long long int hash(String s){
    long long k = 7;
    for(int i = 0; i < s.length(); i++){
        k *= 23;
        k += s[i];
        k *= 13;
        k %= 1000000009;
    }
    return k;
}

这应该会给你一个很好的(对于大多数样本来说是无冲突的)哈希值。