PHP加密算法如何高效转换为Go语言等效代码？

function encrypt($data, $key) {
    $key = md5($key);
    $x = 0;
    $len = strlen($data);
    $l = strlen($key);
    for ($i = 0; $i < $len; $i++) {
        $data[$i] = $data[$i] ^ $key[$x];
        $x++;
        if ($x >= $l) {
            $x = 0;
        }
    }
    return base64_encode($data);
}

package main

import (
    "crypto/md5"
    "encoding/base64"
    "encoding/hex"
    "fmt"
)

func MD5(p string) string {
    h := md5.New()
    h.Write([]byte(p))
    return hex.EncodeToString(h.Sum(nil))
}

func Encrypt(data, key string) string {
    keyBytes := []byte(MD5(key))
    dataBytes := []byte(data)
    x := 0
    length := len(dataBytes)
    l := len(keyBytes)
    for i := 0; i < length; i++ {
        dataBytes[i] = dataBytes[i] ^ keyBytes[x]
        x++
        if x >= l {
            x = 0
        }
    }
    return base64.StdEncoding.EncodeToString(dataBytes)
}

func main() {
    phpEncrypted := encrypt("test", "mykey");
    goEncrypted := Encrypt("test", "mykey");
    fmt.Printf("PHP Encrypted: %s\n", phpEncrypted)
    fmt.Printf("Go Encrypted: %s\n", goEncrypted)

}