RSA公钥生成——Swift

Question

Azure 密钥保管库发送 e 和 n 参数，它们等于 RSA 模数 (n) 和 RSA public exponent(e强>）。使用 3rd 方库很容易创建，但如果没有模数和指数，输出值将无效。

我需要创建这两个部分的 RSA 公钥。然后我必须创建 RSA OAEP。 有没有人遇到过类似的问题？知道如何实现这一目标吗？

我尝试使用 SCZ-BasicEncodingRules-iOS，但它输出的代码不正确。

代码如下：

let moduleString: String = "mK-g0TLMqtefmosgBSTQi3dWh8h-rn4lQA8sQgNs_Gkf5TvgKWtYGJ4jRGUU-eK2bmyAAomVUojYBBlRYBkTRekm99DlD9T6U9yI3v11pZVl3yQgVXBEkiTZug3Inn_IAOGPQ3Q5OT6fEj1sRRxmMv93CQukQguSKuU4v2tmElgvyhg_eKIQbNx0JRCI4-1Z5GazxNjtwk7tWcA6PAbV0zZe2AaW0TlYVil_U8NckgHBguBoTHqVAbzb-MNa-HRa4QlBmdemcSaiDr5GikoOdmQ1-Lu6koqUkepx16pgqPvVw3o_NuXAZCS37c7bfgtXWTJcAIjiQaEyRcIV2bXsUQ"

    let exponent: String = "AQAB"

    let moduleData: NSData! = (moduleString
        as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
    let expData: NSData! = (exponent
        as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
    let arrayaaa: NSArray = [moduleData, expData]
    let key: NSData = arrayaaa.berData()

Answer 1

所以，我找到了解决方案。不幸的是 SCZ-BasicEncodingRules-iOS 对于 iOS 8 及更高版本的解码算法错误。它输出带有错误前缀的键。

如果您遇到同样的问题，这里有一个对我有帮助的解决方案，但它是 Objective-C 代码。 Original source:

   + (NSData *)generateRSAPublicKeyWithModulus:(NSData*)modulus exponent:(NSData*)exponent
{
    const uint8_t DEFAULT_EXPONENT[] = {0x01, 0x00, 0x01,}; //default: 65537
    const uint8_t UNSIGNED_FLAG_FOR_BYTE = 0x81;
    const uint8_t UNSIGNED_FLAG_FOR_BYTE2 = 0x82;
    const uint8_t UNSIGNED_FLAG_FOR_BIGNUM = 0x00;
    const uint8_t SEQUENCE_TAG = 0x30;
    const uint8_t INTEGER_TAG = 0x02;

    uint8_t* modulusBytes = (uint8_t*)[modulus bytes];
    uint8_t* exponentBytes = (uint8_t*)(exponent == nil ? DEFAULT_EXPONENT : [exponent bytes]);

    //(1) calculate lengths
    //- length of modulus
    int lenMod = (int)[modulus length];
    if(modulusBytes[0] >= 0x80)
        lenMod ++;  //place for UNSIGNED_FLAG_FOR_BIGNUM
    int lenModHeader = 2 + (lenMod >= 0x80 ? 1 : 0) + (lenMod >= 0x0100 ? 1 : 0);
    //- length of exponent
    int lenExp = exponent == nil ? sizeof(DEFAULT_EXPONENT) : (int)[exponent length];
    int lenExpHeader = 2;
    //- length of body
    int lenBody = lenModHeader + lenMod + lenExpHeader + lenExp;
    //- length of total
    int lenTotal = 2 + (lenBody >= 0x80 ? 1 : 0) + (lenBody >= 0x0100 ? 1 : 0) + lenBody;

    int index = 0;
    uint8_t* byteBuffer = malloc(sizeof(uint8_t) * lenTotal);
    memset(byteBuffer, 0x00, sizeof(uint8_t) * lenTotal);

    //(2) fill up byte buffer
    //- sequence tag
    byteBuffer[index ++] = SEQUENCE_TAG;
    //- total length
    if(lenBody >= 0x80)
        byteBuffer[index ++] = (lenBody >= 0x0100 ? UNSIGNED_FLAG_FOR_BYTE2 : UNSIGNED_FLAG_FOR_BYTE);
    if(lenBody >= 0x0100)
    {
        byteBuffer[index ++] = (uint8_t)(lenBody / 0x0100);
        byteBuffer[index ++] = lenBody % 0x0100;
    }
    else
        byteBuffer[index ++] = lenBody;
    //- integer tag
    byteBuffer[index ++] = INTEGER_TAG;
    //- modulus length
    if(lenMod >= 0x80)
        byteBuffer[index ++] = (lenMod >= 0x0100 ? UNSIGNED_FLAG_FOR_BYTE2 : UNSIGNED_FLAG_FOR_BYTE);
    if(lenMod >= 0x0100)
    {
        byteBuffer[index ++] = (int)(lenMod / 0x0100);
        byteBuffer[index ++] = lenMod % 0x0100;
    }
    else
        byteBuffer[index ++] = lenMod;
    //- modulus value
    if(modulusBytes[0] >= 0x80)
        byteBuffer[index ++] = UNSIGNED_FLAG_FOR_BIGNUM;
    memcpy(byteBuffer + index, modulusBytes, sizeof(uint8_t) * [modulus length]);
    index += [modulus length];
    //- exponent length
    byteBuffer[index ++] = INTEGER_TAG;
    byteBuffer[index ++] = lenExp;
    //- exponent value
    memcpy(byteBuffer + index, exponentBytes, sizeof(uint8_t) * lenExp);
    index += lenExp;

    if(index != lenTotal)
        NSLog(@"lengths mismatch: index = %d, lenTotal = %d", index, lenTotal);

    NSMutableData* buffer = [NSMutableData dataWithBytes:byteBuffer length:lenTotal];
    free(byteBuffer);

    return buffer;
}

此算法与标准 Java KeyFactory 生成类匹配。