golang 中签名问题求助

[usufu]

求助各位大神，java 当中的

RSAPrivateCrtKeySpec rsaPriKey = new RSAPrivateCrtKeySpec(modulus, publicExponent, privateExponent, primeP, primeQ, primeExponentP, primeExponentQ, crtCoefficient);
KeyFactory keyf = KeyFactory.getInstance("RSA");
PrivateKey key = keyf.generatePrivate(rsaPriKey);

String input = "测试";
Signature signature = Signature.getInstance("SHA1withRSA");
signature.initSign(key);
signature.update(input.getBytes("utf-8"));

用 go 怎么实现，有没有相应的包？尤其是第一部分根据一堆参数生成 rsa key 的部分没有找到 go 怎么写。

[neighbads]

https://godoc.org/crypto/rsa

[usufu]

没找到该用那个方法

[qwerthhusn]

其实 RSA 私钥就两个字段 PrivateExponent 和 modules，只要有个这两个其他的就能算出来

[usufu]

研究了一下，解决了。记录如下：
```
pubkey := rsa.PublicKey{
N:Modulus,
E:int(Exponent.Int64()),
}

preValues := rsa.PrecomputedValues{
Dp:DP,
Dq:DQ,
Qinv:InverseQ,
}

priKey := rsa.PrivateKey{
PublicKey: pubkey,
D:D,
Primes: []*big.Int{P, Q},
Precomputed:preValues,
}
derBytes := x509.MarshalPKCS1PrivateKey(&priKey)
PrivateKey, _ := x509.ParsePKCS1PrivateKey(derBytes)

rand := rand.Reader
msg := []byte("the message to be signed...")
hashed := sha1.Sum(msg)
signbyte, err := rsa.SignPKCS1v15(rand, PrivateKey, crypto.SHA1, hashed[:])
if err != nil {
log.Fatal(err)
}
signature := base64.StdEncoding.EncodeToString(signbyte)
fmt.Println(signature)
expresult := `NDarItrQEHlpT6jAOmz/OgL/nahM1tesCQyN3NcYU8b+O0QPElP3hIQJlYklZnxJaoUZON+8Ja5R+b3lODcsXesRm81bypYCzF5sjPu8P2jvS4A4RE2T3+Pn+JRgUhu5ilxZcrCVYDt1buKcN5uC+VEb+ixSgvWQHY835UCGqow=`
if strings.Compare(signature, expresult) == 0 {
fmt.Println("signature correct...")
} else {
fmt.Println("Signature NOT correct...")
}
```