package utils

import (
	"crypto"
	"crypto/rsa"
	"crypto/sha256"
	"crypto/x509"
	"encoding/pem"
	"fmt"
)

// 解析PKCS1公钥
// https://uutool.cn/rsa-generate/
func ParsePKCS1PublicKey(publicKeyPEM string) (*rsa.PublicKey, error) {
	block, _ := pem.Decode([]byte(publicKeyPEM))
	if block == nil {
		return nil, fmt.Errorf("无效的公钥 -----BEGIN RSA PUBLIC KEY----- 编码")
	}

	pubKey, err := x509.ParsePKCS1PublicKey(block.Bytes)
	if err != nil {
		return nil, err
	}

	return pubKey, nil
}

// 验证签名
func VerifySignature(publicKey *rsa.PublicKey, data, signature []byte) bool {
	hashed := sha256.Sum256(data)
	err := rsa.VerifyPKCS1v15(publicKey, crypto.SHA256, hashed[:], signature)

	return err == nil
}