Extracting PrivateKey from an APNS Push Certificate (p12)

Hi, my question is regarding APNs p12 files downloadable from Apple Dev Accounts.

I want to

• download the push certificate for the server from Apple Dev Account

• get the alias

• get the certificate

• get the private key

I send this info later to a server for enabling push notifications.

Issue:
I could make a function to get the SecIdentity from the p12 file, but when extracting the private key Data for converting later to String, I get an error with the passphrase.

The issue is only reproducible in macOS, as in iOS works fine.

Code Block 
func buildAPNs(_ p12: NSData, _ password: String) throws -> ApplePushCertificate {
				var alias : CFString? = nil
				var cert: SecCertificate? = nil
				var privateKey: SecKey? = nil
				/* loadP12 does:
				 let keychain = try makeTemporaryKeyChain()
				 let passData = NSData(data: password.data(using: .utf8)!) as CFData
				 let options : NSDictionary = [key: passData, keychainKey: keychain!]
				 var items : CFArray? = NSArray() as CFArray
				 let status: OSStatus = SecPKCS12Import(p12, options, &items)
				 */
				let (securityError, rawItems, keychain) = try loadP12(p12: p12, password: password)
				let items = rawItems! as! Array<Dictionary<String, Any>>
				if securityError == errSecSuccess && items.count > 0 {
						if let secIdentity = (items[0])[kSecImportItemIdentity as String] as! SecIdentity? {
								let certSecurityError = SecIdentityCopyCertificate(secIdentity, &cert)
								let aliasSecurityError = SecCertificateCopyCommonName(cert!, &alias)
								let pkSecurityError = SecIdentityCopyPrivateKey(secIdentity, &privateKey)
								guard pkSecurityError == errSecSuccess else {
										throw NSError(domain: "Error with pk", code: Int(pkSecurityError), userInfo: nil)
								}
								guard certSecurityError == errSecSuccess else {
										throw NSError(domain: "Error with certificate", code: Int(pkSecurityError), userInfo: nil)
								}
								guard aliasSecurityError == noErr else {
										throw NSError(domain: "Error with alias", code: Int(pkSecurityError), userInfo: nil)
								}
						}
				}
				return ApplePushCertificate(alias: String(alias!),
																		certificate: cert!,
																		privateKey: privateKey!,
																		keychain: keychain)
		}

with this ApplePushCertificate I call

Code Block 
func getKeyData(apnsCert: ApplePushCertificate)-> String {
let keyData = SecKeyCopyExternalRepresentation(apnsCert.privateKey, &error)
//call (keyData as Data).base64EncodedString()
}

the error when trying to create keyData is:

Code Block 
Error Domain=NSOSStatusErrorDomain Code=-25260 "MacOS error: -25260" UserInfo={NSDescription=MacOS error: -25260}

How can I solve this issue for MacOS?
I tried the same code (without creating a temporary keychain) in iOS and works fine without errors