Question

我需要一个快速校验和（尽可能快）用于小字符串（20-500个字符）。

我需要源代码，而且必须很小！（最多约100 LOC）

如果它可以在Base32 / 64中生成字符串。（或类似的东西）它会是完美的。基本上校验和不能使用任何“坏”字符..你知道..通常（）{} []。，;：/ + - \ |等

澄清

它可能是强弱的，这无关紧要，因为它仅用于幕后目的。

它不需要包含原始字符串的所有数据，因为我只会与生成的校验和进行比较，我不期望任何类型的“解密”。

Answer 1

schnaader的实施确实非常快。这是在Javascript：

function checksum(s) { var chk = 0x12345678; var len = s.length; for (var i = 0; i < len; i++) { chk += (s.charCodeAt(i) * (i + 1)); } return (chk & 0xffffffff).toString(16); }

使用谷歌浏览器，此功能仅需5毫秒即可运行1兆字节的字符串，而使用crc32功能则需要330毫秒。

Answer 2

在C中快速实施，没有我的版权，所以请按照您的意愿使用它。但请注意，这是一个非常弱的“校验和”，所以不要将它用于严肃的事情:) - 但这就是你想要的，不是吗？

这将返回一个32位整数校验和，编码为包含其十六进制值的字符串。如果校验和函数不能满足您的需求，您可以将chk += ((int)(str[i]) * (i + 1));行更改为更好的（f.e。乘法，加法和按位旋转会更好）。

编辑：根据hughdbrown的建议和one of the answers he linked，我更改了for循环，因此每次迭代都不会调用strlen。

#include <stdio.h>
#include <stdlib.h>
#include <string>

char* hextab = "0123456789ABCDEF";

char* encode_int(int i) {
  char* c = (char*)malloc(sizeof(char) * 9);

  for (int j = 0; j < 4; j++) {
    c[(j << 1)] = hextab[((i % 256) >> 4)];
    c[(j << 1) + 1] = hextab[((i % 256) % 16)];

    i = (i >> 8);
  }
  c[8] = 0;

  return c;
}

int checksum(char* str) {
  int i;
  int chk = 0x12345678;

  for (i = 0; str[i] != '\0'; i++) {
    chk += ((int)(str[i]) * (i + 1));
  }

  return chk;
}

int main() {
  char* str1 = "Teststring";
  char* str2 = "Teststring2";

  printf("string: %s, checksum string: %s\n", str1, encode_int(checksum(str1)));
  printf("string: %s, checksum string: %s\n", str2, encode_int(checksum(str2)));

  return 0;
}

Answer 3

这是CRC32的Javascript实现：

function crc32 ( str ) {
    // http://kevin.vanzonneveld.net
    // +   original by: Webtoolkit.info (http://www.webtoolkit.info/)
    // +   improved by: T0bsn
    // -    depends on: utf8_encode
    // *     example 1: crc32('Kevin van Zonneveld');
    // *     returns 1: 1249991249

    str = utf8_encode(str);
    var table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

    var crc = 0;
    var x = 0;
    var y = 0;

    crc = crc ^ (-1);
    for( var i = 0, iTop = str.length; i < iTop; i++ ) {
        y = ( crc ^ str.charCodeAt( i ) ) & 0xFF;
        x = "0x" + table.substr( y * 9, 8 );
        crc = ( crc >>> 8 ) ^ x;
    }

    return crc ^ (-1);
}

找到kevin.vanzonneveld.net

Answer 4

您可以提出的任何算法都符合您的标准。 E.g。

CHECKSUM = SUM( i=0 .. input.length, input[i] )

使其成为“糟糕的安全”

CHECKSUM = 'A' + SUM( i=0 .. input.length, input[i] ) MODULO 26

尝试通过增加输出域来减少冲突次数

# Assume BASE64[ ] is the safe output alphabet array.
TMP = SUM( i=0 .. input.length, input[i] ) MODULO 2^24
FOR I = 0..3
    CHECKSUM[I] = BASE64[TMP MODULO 64]
    TMP = TMP / 64

通过计算不同渗透的不同值来进一步减少碰撞次数的解决方案

# Assume BASE64[ ] is the safe output alphabet array.
TMP = SUM( i=0 .. input.length, i*input[i] ) MODULO 2^24
FOR I = 0..3
    CHECKSUM[I] = BASE64[TMP MODULO 64]
    TMP = TMP / 64

一般来说，如果输入足够随机且足够稀疏（当然，“足够”在每种情况下都不同），所有这些变化都表现得非常好。

Answer 5

它是207行，但它是md5的javascript实现：

http://www.webtoolkit.info/javascript-md5.html

将它与javascript base64结合使用：

http://www.webtoolkit.info/javascript-base64.html

这些脚本是完全自包含的，因此它们有一些冗余（例如UTF-8编码/解码），可以很容易地使它们共用。

编辑：在同一网站上，您可以找到一个javascript crc32：

http://www.webtoolkit.info/javascript-crc32.html

Answer 6

只使用javascript你可以使用这个crc函数：http://www.webtoolkit.info/javascript-crc32.html

/**
*
*  Javascript crc32
*  http://www.webtoolkit.info/
*
**/

function crc32 (str) {

    function Utf8Encode(string) {
        string = string.replace(/\r\n/g,"\n");
        var utftext = "";

        for (var n = 0; n < string.length; n++) {

            var c = string.charCodeAt(n);

            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }

        }

        return utftext;
    };

    str = Utf8Encode(str);

    var table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

    if (typeof(crc) == "undefined") { crc = 0; }
    var x = 0;
    var y = 0;

    crc = crc ^ (-1);
    for( var i = 0, iTop = str.length; i < iTop; i++ ) {
        y = ( crc ^ str.charCodeAt( i ) ) & 0xFF;
        x = "0x" + table.substr( y * 9, 8 );
        crc = ( crc >>> 8 ) ^ x;
    }

    return crc ^ (-1);

};

在php中你可以用一行md5哈希来做，在一个长度为20到500的字符串上它应该很快

$hash_code = md5($string_to_hash);

这里有更多信息：http://us.php.net/md5

另外，如果您想选择哈希算法，可以使用哈希php函数：http://us.php.net/manual/en/function.hash.php

Answer 7

您正在寻找的是一种为字符串创建哈希码的算法。在C＃中：

byte[] bytesToHash = Encoding.UTF8.GetBytes(stringToHash);
HashAlgorithm sha = new SHA1CryptoServiceProvider();
byte[] hash = sha.ComputeHash(dataArray);
string result = Convert.ToBase64String(hash);

Answer 8

md5sum，sha1sum，sha224sum，sha256sum，sha384sum，sha512sum可用于大多数* nix发行版

Answer 9

这似乎有些迟了，而且有些偏离主题了……我在基于JS和PHP的应用程序中使用了joelpt's JS-implementation中的schnaader's solution。而且，我认为PHP实现也可能对其他人有所帮助。

function checksum($s) {
    $chk = 0x12345678;
    $len = mb_strlen($s);
    for ($i = 0; $i < $len; $i++) {
        $chk += (mb_ord(mb_substr($s, $i, 1)) * ($i + 1));
    }
    return dechex($chk & 0xffffffff);
}

if (!function_exists('mb_ord')) {
    // Shim from https://stackoverflow.com/a/1365610/336311
    function mb_ord($string) {
        mb_internal_encoding('UTF-8');
        // mb_language('Neutral');
        // mb_detect_order(['UTF-8', 'ISO-8859-15', 'ISO-8859-1', 'ASCII']);

        $result = unpack('N', mb_convert_encoding($string, 'UCS-4BE', 'UTF-8'));

        if (is_array($result)) {
            return $result[1];
        }
        return ord($string);
    }
}

Answer 10

要在现代（非IE）浏览器中运行，必须在HTTPS上运行：

https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/digest

const text = `Lorem ipsum dolor sit amet, consectetur adipiscing elit. In nec elit a justo rhoncus blandit. Aenean commodo sem in mattis fermentum. Phasellus pellentesque tortor lectus, a sodales quam cursus in. Aliquam lorem velit, faucibus id nisi sed, tristique tempor odio. Donec sit amet neque non nunc dictum gravida. Vestibulum in suscipit urna, ac porttitor enim. Integer ultrices feugiat justo vel gravida. Cras viverra laoreet lobortis. Mauris non pharetra purus. Aenean sed elementum justo. Vivamus libero enim, consequat eu convallis in, lacinia ut mi. Curabitur eget diam id augue tincidunt tempus ac eu nisi. Sed dui leo, rhoncus vel egestas non, tempor a magna.

Donec congue vehicula nunc sed vestibulum. Interdum et malesuada fames ac ante ipsum primis in faucibus. Donec sodales scelerisque ullamcorper. Sed iaculis aliquet consectetur. Donec vel purus sodales, interdum velit eget, ultricies arcu. Nullam eu lorem vel sem aliquam congue eu ut felis. Praesent auctor vitae massa venenatis bibendum. Morbi a aliquet enim. Mauris ac nisi lacus. Etiam nec sollicitudin nibh. Sed maximus tortor eget lectus maximus, quis ultrices justo faucibus. Suspendisse potenti. Fusce id consequat mi.

Donec cursus, orci vel malesuada porttitor, nisi orci volutpat ipsum, eget pretium nisl est a lorem. Curabitur et egestas tortor, vel mattis tellus. Suspendisse eget nunc varius, pharetra velit sit amet, viverra est. Pellentesque a vehicula risus, eu tincidunt justo. Sed nec ligula a eros sagittis rhoncus. Vestibulum a nulla erat. Nulla facilisi. Aenean elit diam, scelerisque quis sollicitudin non, feugiat a lorem.

Aliquam lacinia mi diam, ut aliquet libero placerat at. Pellentesque sit amet neque varius, pharetra nunc ac, egestas justo. Fusce at dapibus felis, et imperdiet felis. Nullam fringilla mi ut lorem imperdiet cursus. Morbi venenatis, justo vel efficitur euismod, dui lacus tincidunt neque, vel vestibulum velit lectus et velit. Sed non dolor libero. Vivamus nec ligula a nisl eleifend sollicitudin at id nisl. Sed in vestibulum nisi, sed vestibulum nunc. Donec volutpat eu nisi nec venenatis.

Sed rhoncus ut nisl a tristique. Integer lacus massa, congue fringilla mollis in, pretium vitae lorem. Vivamus porttitor quam nisl, vitae suscipit ante egestas at. Ut sed enim vel ante congue euismod sit amet a elit. Phasellus sed placerat nunc. Aenean turpis tortor, convallis eget leo a, fringilla fringilla nisi. Maecenas euismod sapien ut massa ultricies interdum. Donec suscipit dolor dolor.`;

async function digestMessage(message) {
  // encode as (utf-8) Uint8Array
  const msgUint8 = new TextEncoder().encode(message);
  // hash the message
  const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8);
  // convert buffer to byte array
  const hashArray = Array.from(new Uint8Array(hashBuffer));
  // convert bytes to hex string
  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
  return hashHex;
}

const digestBuffer = digestMessage(text)
  .then(digestBuffer => console.log(digestBuffer));

以上内容大约需要4.5毫秒，简短的句子与长长的句子没有区别。没有尝试很长的字符串。

小字符串的快速开源校验和

10 个答案: