[iOS] KeyChain 의 Key (SecKeyRef) 를 NSData 형식으로 변경하기

출처

https://stackoverflow.com/questions/16748993/ios-seckeyref-to-nsdata

https://developer.apple.com/documentation/security/certificate_key_and_trust_services/keys/storing_keys_as_data?language=objc

iOS 10 이상에서의 Security.framework 가 

SecKeyRef -> NSData *, NSData * -> SecKeyRef 로 변경하는 메소드를 제공한다.

SecKeyRef -> NSData * 로 변경하기 

CFErrorRef cfError = NULL;

    NSData *keyData = (__bridge_transfer NSData *)SecKeyCopyExternalRepresentation(publicKeyRef, &cfError);

if (!keyData) {

    NSError *keyError = (__bridge_transfer NSError *)cfError;

    if (error && keyError) {

        *error = keyError;

    }

    return NO;

}

NSData * -> SecKeyRef 로 변경하기

NSDictionary *options = @{

        (id)kSecAttrKeyType : (id)kSecAttrKeyTypeRSA,

        (id)kSecAttrKeyClass : (id)kSecAttrKeyClassPublic,

        (id)kSecAttrKeySizeInBits : @2048,

};

CFErrorRef cfError = NULL;

SecKeyRef key = SecKeyCreateWithData((__bridge CFDataRef)decData,

    (__bridge CFDictionaryRef)options, &cfError);

if (!key) {

    NSError *keyError = (__bridge_transfer NSError *)cfError;

    if (error && keyError) {

        *error = keyError;

    }

    return nil;

}