JavaScript代码中如何实现腾讯优图里的HMAC-SHA1 算法进行签名

[qq_34030763]

微信小程序里利用腾讯优图提供的接口进行图像识别的工作。但鉴权一直不通过。在网上搜索了JavaScript的HMAC-SHA1 算法对信息加密。但服务器一直返回403错误代码。表示鉴权信息不合法，禁止访问。该如何解决。

以下是我所使用的HMAC-SHA1 算法
var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */
var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */
var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode */


function hex_sha1(s) { return binb2hex(core_sha1(str2binb(s), s.length * chrsz)); }
function b64_sha1(s) { return binb2b64(core_sha1(str2binb(s), s.length * chrsz)); }
function str_sha1(s) { return binb2str(core_sha1(str2binb(s), s.length * chrsz)); }
function hex_hmac_sha1(key, data) { return binb2hex(core_hmac_sha1(key, data)); }
function b64_hmac_sha1(key, data) { return binb2b64(core_hmac_sha1(key, data)); }
function str_hmac_sha1(key, data) { return binb2str(core_hmac_sha1(key, data)); }

/*
* Perform a simple self-test to see if the VM is working
*/
function sha1_vm_test() {
return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";
}

/*
* Calculate the SHA-1 of an array of big-endian words, and a bit length
*/
function core_sha1(x, len) {
/* append padding */
x[len >> 5] |= 0x80 << (24 - len % 32);
x[((len + 64 >> 9) << 4) + 15] = len;

var w = Array(80);
var a = 1732584193;
var b = -271733879;
var c = -1732584194;
var d = 271733878;
var e = -1009589776;

for (var i = 0; i < x.length; i += 16) {
var olda = a;
var oldb = b;
var oldc = c;
var oldd = d;
var olde = e;

for (var j = 0; j < 80; j++) {
if (j < 16) w[j] = x[i + j];
else w[j] = rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),
safe_add(safe_add(e, w[j]), sha1_kt(j)));
e = d;
d = c;
c = rol(b, 30);
b = a;
a = t;
}

a = safe_add(a, olda);
b = safe_add(b, oldb);
c = safe_add(c, oldc);
d = safe_add(d, oldd);
e = safe_add(e, olde);
}
return Array(a, b, c, d, e);

}

/*
* Perform the appropriate triplet combination function for the current
* iteration
*/
function sha1_ft(t, b, c, d) {
if (t < 20) return (b & c) | ((~b) & d);
if (t < 40) return b ^ c ^ d;
if (t < 60) return (b & c) | (b & d) | (c & d);
return b ^ c ^ d;
}

/*
* Determine the appropriate additive constant for the current iteration
*/
function sha1_kt(t) {
return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :
(t < 60) ? -1894007588 : -899497514;
}

/*
* Calculate the HMAC-SHA1 of a key and some data
*/
function core_hmac_sha1(key, data) {
var bkey = str2binb(key);
if (bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);

var ipad = Array(16), opad = Array(16);
for (var i = 0; i < 16; i++) {
ipad[i] = bkey[i] ^ 0x36363636;
opad[i] = bkey[i] ^ 0x5C5C5C5C;
}

var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);
return core_sha1(opad.concat(hash), 512 + 160);
}

/*
* Add integers, wrapping at 2^32. This uses 16-bit operations internally
* to work around bugs in some JS interpreters.
*/
function safe_add(x, y) {
var lsw = (x & 0xFFFF) + (y & 0xFFFF);
var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
}

/*
* Bitwise rotate a 32-bit number to the left.
*/
function rol(num, cnt) {
return (num << cnt) | (num >>> (32 - cnt));
}

/*
* Convert an 8-bit or 16-bit string to an array of big-endian words
* In 8-bit function, characters >255 have their hi-byte silently ignored.
*/
function str2binb(str) {
var bin = Array();
var mask = (1 << chrsz) - 1;
for (var i = 0; i < str.length * chrsz; i += chrsz)
bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (32 - chrsz - i % 32);
return bin;
}

/*
* Convert an array of big-endian words to a string
*/
function binb2str(bin) {
var str = "";
var mask = (1 << chrsz) - 1;
for (var i = 0; i < bin.length * 32; i += chrsz)
str += String.fromCharCode((bin[i >> 5] >>> (32 - chrsz - i % 32)) & mask);
return str;
}

/*
* Convert an array of big-endian words to a hex string.
*/
function binb2hex(binarray) {
var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
var str = "";
for (var i = 0; i < binarray.length * 4; i++) {
str += hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8 + 4)) & 0xF) +
hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8)) & 0xF);
}
return str;
}

/*
* Convert an array of big-endian words to a base-64 string
*/
function binb2b64(binarray) {
var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var str = "";
for (var i = 0; i < binarray.length * 4; i += 3) {
var triplet = (((binarray[i >> 2] >> 8 * (3 - i % 4)) & 0xFF) << 16)
| (((binarray[i + 1 >> 2] >> 8 * (3 - (i + 1) % 4)) & 0xFF) << 8)
| ((binarray[i + 2 >> 2] >> 8 * (3 - (i + 2) % 4)) & 0xFF);
for (var j = 0; j < 4; j++) {
if (i * 8 + j * 6 > binarray.length * 32) str += b64pad;
else str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3F);
}
}
return str;
}