iOS使用security.framework实现RSA加解密_(__bridge cfdataref)

最近研究了下使用security.framework框架进行RSA加解密。从cer证书文件中读取公钥，从pfx证书文件中读取私钥。

1、从cer证书文件中读取公钥

/**
 *  获取公钥
 *
 *  @return
 */
- (SecKeyRef)getPublicKey {
    if (!_publicKey) {
        [self loadPublicKeyFromFile:self.cerFilePath];
    }
    return _publicKey;
}
 
/**
 *  通过文件路径加载公钥
 *
 *  @param cerFilePath 公钥文件路径
 */
- (void)loadPublicKeyFromFile:(NSString *)cerFilePath {
    if (self.cerFilePath == nil) {
        return;
    }
    NSData *cerData = [[NSData alloc] initWithContentsOfFile:cerFilePath];
    [self loadPublicKeyFromData:cerData];
}
 
/**
 *  通过NSData加载公钥
 *  （此方法可用于将公钥配置在服务端，以Base64字符串传到移动端来加载）
 *  @param derData 公钥data
 */
- (void)loadPublicKeyFromData:(NSData *)cerData {
    _publicKey = [self getPublicKeyRefrenceFromeData:cerData];
}
 
#pragma mark - Private Methods
 
/**
 *  （私有方法）从data获取公钥
 *
 *  @param derData data
 *
 *  @return 公钥
 */
- (SecKeyRef)getPublicKeyRefrenceFromeData:(NSData *)certData {
    SecKeyRef publicKeyRef = NULL;
    CFDataRef myCertData = (__bridge CFDataRef)certData;
    SecCertificateRef cert = SecCertificateCreateWithData(NULL, (CFDataRef)myCertData);
    if (cert == nil) {
        NSLog(@"Can not read certificate from %@", self.cerFilePath);
        return nil;
    }
    SecPolicyRef policy = SecPolicyCreateBasicX509();
    SecCertificateRef certArray[1] = {cert};
    CFArrayRef myCerts = CFArrayCreate(NULL, (void *)certArray,1, NULL);
    SecTrustRef trust;
    OSStatus