使用X.509加密iOS中的2048位公钥

Question

在我的iOS库中，我有一个包含X.509 RSA 2048位公钥的Base64编码字符串。我想用这个公钥加密一个字符串。任何人都可以提供一些Objective C代码参考，提到我需要包含的库？

相应的Java代码看起来如下：

byte[] keyBytes = Base64.decodeBase64(publicKeyData); 
// Get Public Key 
X509EncodedKeySpec rsaPublicKeySpec = new X509EncodedKeySpec(keyBytes); 
KeyFactory fact = KeyFactory.getInstance("RSA"); 
PublicKey publicKey = fact.generatePublic(rsaPublicKeySpec); 
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); 
cipher.init(Cipher.ENCRYPT_MODE, pubKey); 
encryptedData = cipher.doFinal(dataToEncrypt); 

Answer 1

试试这个代码：

// publicKeyBase64 is your public key string 
NSData *publicKeyFileContent = [[NSData alloc] initWithBase64EncodedString:publicKeyBase64 options:0]; 

// get your public key 
SecCertificateRef cert = SecCertificateCreateWithData(kCFAllocatorDefault, (__bridge CFDataRef)publicKeyFileContent); 
SecPolicyRef policy = SecPolicyCreateBasicX509(); 
SecTrustRef trust; 
OSStatus status = SecTrustCreateWithCertificates(cert, policy, &trust); 
SecTrustResultType trustResult; 
if (status == noErr) { 
    status = SecTrustEvaluate(trust, &trustResult); 
} 
SecKeyRef keyRef = SecTrustCopyPublicKey(trust); 

// encrypt your data 
// with this code you can encrypt only one block 
// if you need to encrypt more data you need to use some chunking logic 
const uint8_t *srcbuf = (const uint8_t *)[data bytes]; 
size_t srclen = (size_t)data.length; 
size_t outlen = SecKeyGetBlockSize(keyRef) * sizeof(uint8_t); 
if(srclen > outlen - 11){ 
    CFRelease(keyRef); 
    return nil; 
} 
void *outbuf = malloc(outlen); 

OSStatus status = noErr; 
status = SecKeyEncrypt(keyRef, 
         kSecPaddingPKCS1, 
         srcbuf, 
         srclen, 
         outbuf, 
         &outlen 
         ); 
NSData *ret = nil; 
if (status != 0) { 
    NSLog(@"SecKeyEncrypt fail. Error Code: %ld", status); 
}else{ 
    ret = [NSData dataWithBytes:outbuf length:outlen]; 
} 
free(outbuf); 
CFRelease(cert); 
CFRelease(policy); 
CFRelease(trust); 
CFRelease(keyRef); 
// your encrypted data is in ret