将Node.js私钥签名代码迁移至Swift的算法适配问题

我正尝试将一段通过私钥生成签名的Node.js代码移植到Swift环境中。私钥通过以下OpenSSL命令生成：

openssl genrsa -des3 -out WM_IO_my_rsa_key_pair 2048 

可正常运行的Node.js代码 #

const crypto = require('crypto');
const fs = require("fs");

(async () => {
    const privateKey = await fs.promises.readFile("./keys/in.pem");
    const string = "Hello World"
    const sign = crypto.createSign('sha256');
    sign.write(string);
    sign.end();

    const signature = sign.sign({ 
        key: privateKey
    }); 

    const signature_enc = signature.toString("base64");
    console.log(signature_enc);
})()

Swift尝试代码及疑问 #

为适配Swift，我通过以下OpenSSL命令从.pem文件导出私钥：

openssl rsa -in in.pem -out out.pem

我的Swift代码如下，但无法确定应使用哪种签名算法来生成与Node.js一致的签名：

import UIKit
import Security
import CommonCrypto

func createKey(pem: String) -> SecKey? {
    let attributes: [NSObject : NSObject] = [
       kSecAttrKeyType: kSecAttrKeyTypeRSA,
       kSecAttrKeyClass: kSecAttrKeyClassPrivate,
       kSecAttrKeySizeInBits: NSNumber(value: 2048)
    ]

    let privateKey = pem
        .replacingOccurrences(of: "-----BEGIN RSA PRIVATE KEY-----", with: "")
        .replacingOccurrences(of: "-----END RSA PRIVATE KEY-----", with: "")
        .split(separator: "\n").joined()

    guard let privateKeyData = Data(base64Encoded: privateKey, options: .ignoreUnknownCharacters) else {
        return nil
    }

    var error: Unmanaged<CFError>?
    return SecKeyCreateWithData(privateKeyData as CFData, attributes as CFDictionary, &error)
}

func createHash(string: String) -> Data {
    let hash = UnsafeMutablePointer<UInt8>.allocate(capacity: Int(CC_SHA256_DIGEST_LENGTH))
    let hashLength = string.count
    defer { hash.deallocate() }
    CC_SHA256(string, CC_LONG(hashLength), hash)
    return Data(bytes: hash, count: hashLength)
}

let privateKey = """
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
"""

if let key = createKey(pem: privateKey) {
    // Create hash
    let hash = createHash(string: "Hello World")
    
    var error: Unmanaged<CFError>?
    if let signature = SecKeyCreateSignature(key, .rsaSignatureMessagePKCS1v15SHA256, hash as CFData, &error) as Data? {
        let signiture64 = signature.base64EncodedString()
    }
}

需要帮助确定正确的签名算法，使Swift代码生成与Node.js一致的签名。

内容的提问来源于stack exchange，提问作者Berry Blue