Node.js中的XML到PEM [英] XML to PEM in Node.js

问题描述

我遇到了crypto api，因为我对密码学知之甚少。我有这个

I'm stuck with the crypto api because I know little about cryptography. I have this

XML:
<RSAKeyValue>
    <Modulus>1znidPBIcMcO7K/53tkTSyKqxlG5Mcws8kVtijS4tyEU4W/FEVWYpOtv+Stnb4Vt</Modulus>
    <Exponent>AQAB</Exponent>
</RSAKeyValue>

Signature:
rNbdUP-p4pEGfwQSwR6VPvAVZ-sZu-ptgw8SofYYmNTlfUB9iUbb593eCAuT5jsqDTC

Original data:
<xml>...some big xml...</xml>

我要验证签名，我该怎么办？

I want to verify the signature, how do I do that?

（我使用节点v0.10.18）

(I'm using node v0.10.18)

推荐答案

js dev，所以这是超级hacky ..这里是一个函数，应该输出一个RSA公钥PEM从Base64模数和指数。我将基于Trevor关于node.js 的验证预期一个PEM。

I'm not really a node.js dev, so this is super hacky.. Here's a function that should output a RSA public key PEM from Base64 modulus and exponent. I'm going based on Trevor's comment about node.js verify expecting a PEM.

这个函数组成一个ASN .1十六进制的DER结构，然后十六进制解码，然后base64编码它，然后将其夹在 ----- BEGIN PRIVATE KEY ----- 和 ----- END PRIVATE KEY ----- 。毕竟，这是一个PEM。

This function composes a ASN.1 DER structure in hex, then hex-decodes it, then base64-encodes it, and then sandwiches it between -----BEGIN PRIVATE KEY----- and -----END PRIVATE KEY-----. After all, that's all a PEM is.

function rsaPublicKeyPem(modulus_b64, exponent_b64) {

    function prepadSigned(hexStr) {
        msb = hexStr[0]
        if (
            (msb>='8' && msb<='9') || 
            (msb>='a' && msb<='f') || 
            (msb>='A'&&msb<='F')) {
            return '00'+hexStr;
        } else {
            return hexStr;
        }
    }

    function toHex(number) {
        var nstr = number.toString(16)
        if (nstr.length%2==0) return nstr
        return '0'+nstr
    }

    // encode ASN.1 DER length field
    // if <=127, short form
    // if >=128, long form
    function encodeLengthHex(n) {
        if (n<=127) return toHex(n)
        else {
            n_hex = toHex(n)
            length_of_length_byte = 128 + n_hex.length/2 // 0x80+numbytes
            return toHex(length_of_length_byte)+n_hex
        }
    }

    var modulus = new Buffer(modulus_b64,'base64');
    var exponent = new Buffer(exponent_b64, 'base64');

    var modulus_hex = modulus.toString('hex')
    var exponent_hex = exponent.toString('hex')

    modulus_hex = prepadSigned(modulus_hex)
    exponent_hex = prepadSigned(exponent_hex)

    var modlen = modulus_hex.length/2
    var explen = exponent_hex.length/2

    var encoded_modlen = encodeLengthHex(modlen)
    var encoded_explen = encodeLengthHex(explen)
    var encoded_pubkey = '30' + 
        encodeLengthHex(
            modlen + 
            explen + 
            encoded_modlen.length/2 + 
            encoded_explen.length/2 + 2
        ) + 
        '02' + encoded_modlen + modulus_hex +
        '02' + encoded_explen + exponent_hex;

    var seq2 = 
        '30 0d ' +
          '06 09 2a 86 48 86 f7 0d 01 01 01' +
          '05 00 ' +
        '03' + encodeLengthHex(encoded_pubkey.length/2 + 1) +
        '00' + encoded_pubkey;

    seq2 = seq2.replace(/ /g,'');

    var der_hex = '30' + encodeLengthHex(seq2.length/2) + seq2;

    der_hex = der_hex.replace(/ /g, '');

    var der = new Buffer(der_hex, 'hex');
    var der_b64 = der.toString('base64');

    var pem = '-----BEGIN PUBLIC KEY-----\n' 
        + der_b64.match(/.{1,64}/g).join('\n') 
        + '\n-----END PUBLIC KEY-----\n';

    return pem
}

使用十六进制字符串的二进制操作？ Yuck ..但是它是一个黑客。

Binary manipulation with hex strings? Yuck.. but hey it's a hack.

这篇关于Node.js中的XML到PEM的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！