iPhone公钥加密SecKeyEncrypt返回错误9809（errSSLCrypto） [英] iPhone Public-Key Encryption SecKeyEncrypt returns error 9809 (errSSLCrypto)

问题描述

我正在尝试使用iPhone的PKI库加密短字符串（12345678），但每当我尝试使用SecKeyEncrypt时，我都会收到错误-9809（即errSSLCrypto）。 SecureTransport.h头文件将此错误简单地描述为底层加密错误，这不是很有意义。

I am trying to use the iPhone's PKI libraries to encrypt a short string (12345678), but I keep getting the error -9809 (i.e. errSSLCrypto) whenever I try to use SecKeyEncrypt. The SecureTransport.h header file describes this error simply as "underlying cryptographic error", which wasn't very meaningful.

我的代码如下：

- (NSData *)encryptDataWithPublicKey:(NSString *)plainText {

    OSStatus result = -1;

    NSData *plainTextData = [plainText dataUsingEncoding:NSASCIIStringEncoding];
    size_t plainTextLength = [plainTextData length];

    SecTrustRef trustRef;
    SecTrustResultType trustResult;

    SecPolicyRef policy = SecPolicyCreateBasicX509();

    result = SecTrustCreateWithCertificates(m_oCert, policy, &trustRef);

    if (result != errSecSuccess) {
        NSLog(@"Trust create failed with code: %d",result);
        return nil;
    }

    result = SecTrustEvaluate(trustRef, &trustResult);

    if (result != errSecSuccess) {
        NSLog(@"Trust eval failed with code: %d",result);

        CFRelease(trustRef);
        return nil;
    }

    SecKeyRef publicKey = SecTrustCopyPublicKey(trustRef);

    uint8_t *cipherTextBuf = NULL;
    size_t cipherTextLen = 0;

    size_t keyBlockSize = SecKeyGetBlockSize(publicKey);
    int maxInputSize = keyBlockSize - 11; //If using PKCS1 Padding, else keyBlockSize

    if (plainTextLength > maxInputSize) {
        //Fail
        NSLog(@"Data size is larger than max permitted!");

        CFRelease(trustRef);
        CFRelease(publicKey);
        CFRelease(policy);

        return nil;
    }

    cipherTextBuf = malloc(sizeof(uint8_t)*keyBlockSize);
    memset(cipherTextBuf,0,keyBlockSize);

    //result = SecKeyEncrypt(publicKey, kSecPaddingPKCS1, plainTextBuf, plainTextLength, cipherTextBuf, &cipherTextLen);
    result = SecKeyEncrypt(publicKey, kSecPaddingNone, (const uint8_t *)[plainTextData bytes], plainTextLength, cipherTextBuf, &cipherTextLen);

    NSData *cipherText = nil;
    if (result == errSecSuccess) {

        cipherText = [NSData dataWithBytes:cipherTextBuf length:cipherTextLen];

    } else {
        NSLog(@"Error detected: %d",result);
    }

    free(cipherTextBuf);
    cipherTextBuf = NULL;

    CFRelease(trustRef);
    CFRelease(publicKey);
    CFRelease(policy);

    return cipherText;
}

我使用什么填充并不重要，它们都给出了同样的错误。公钥来自我的客户提供的证书，我已经检查以确保密钥有效。我做错了什么以及如何正确使用该功能？

It does not matter what padding I use, they both give the same error. The public key is derived from a certificate supplied by my client, and I've checked to make sure that the key is valid. What am I doing wrong and how do I use the function properly?

推荐答案

使用SecKeyEncrypt时，输入cipherTextLength应该是输出缓冲区的大小。设置

When using SecKeyEncrypt, the input cipherTextLength should be the the size of the output buffer. Setting

size_t cipherTextLen = keyBlockSize;

解决了这个问题。

这篇关于iPhone公钥加密SecKeyEncrypt返回错误9809（errSSLCrypto）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！