常见哈希函数FNV和MD5

// Hash is the common interface implemented by all hash functions.
type Hash interface {
	// Write (via the embedded io.Writer interface) adds more data to the running hash.
	// It never returns an error.
	io.Writer

	// Sum appends the current hash to b and returns the resulting slice.
	// It does not change the underlying hash state.
	Sum(b []byte) []byte

	// Reset resets the Hash to its initial state.
	Reset()

	// Size returns the number of bytes Sum will return.
	Size() int

	// BlockSize returns the hash's underlying block size.
	// The Write method must be able to accept any amount
	// of data, but it may operate more efficiently if all writes
	// are a multiple of the block size.
	BlockSize() int
}

// Writer is the interface that wraps the basic Write method.
//
// Write writes len(p) bytes from p to the underlying data stream.
// It returns the number of bytes written from p (0 <= n <= len(p))
// and any error encountered that caused the write to stop early.
// Write must return a non-nil error if it returns n < len(p).
type Writer interface {
	Write(p []byte) (n int, err error)
}

package main

import (
	"crypto/md5"
	"encoding/hex"
)

func main() {
	m := md5.New()
	m.Write([]byte("hello, world"))
	s := hex.EncodeToString(m.Sum(nil))
	println(s)
}

package main

import "fmt"
import "hash/fnv"
import "encoding/hex"

func main() {
	a := fnv.New32()
	a.Write([]byte("hello"))
	fmt.Println(hex.EncodeToString(a.Sum(nil)))
}