AES 128 GCM目标C osx [英] AES 128 GCM objective C osx

问题描述

我正在目标c中加密/解密AES-128 GCM格式的字符串。我已经看到无处不在，但似乎找不到一个工作的解决方案。

I am trying to encrypt/decrypt a string in an AES-128 GCM format in objective c. I have looked everywhere but can't seem to find a working solution.

推荐答案

不久前我有一个类似的问题我可以找到最好的答案是这一个。总而言之，iOS有一些功能可以做你想要的，但它们是私有的。

Not so long ago I had a similar problem and the best answer I could find was this one. To sum up, iOS has some functions to do what you want but they are private.

所以，直到苹果决定发布这些功能，我选择开发自己的图书馆，目前存储在 GitHub 中，可在 CocoaPods 。

So, until Apple decides to release these functions, I opted for developing my own library, currently stored in GitHub and available in CocoaPods.

您描述的情况可以这样实现：

The case you describe could be implemented this way:

#import <CommonCrypto/CommonCrypto.h>
#import "IAGAesGcm.h"

// For the case you describe, the key length is 128 bits (16 bytes)
u_char keyBytes[kCCKeySizeAES128] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10};
NSData *key = [NSData dataWithBytes:keyBytes length:sizeof(keyBytes)];

// GCM recommends a IV size of 96 bits (12 bytes), but you are free
// to use other sizes
u_char ivBytes[12] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C};
NSData *iv = [NSData dataWithBytes:ivBytes length:sizeof(ivBytes)];

NSData *aad = [@"AdditionalAuthenticatedData" dataUsingEncoding:NSUTF8StringEncoding];

// Authenticated Encryption Function
NSData *expectedPlainData = [@"PlainData" dataUsingEncoding:NSUTF8StringEncoding];

// The returned ciphered data is a simple class with 2 properties: the actual encrypted data and the authentication tag.
// The authentication tag can have multiple sizes and it is up to you to set one, in this case the size is 128 bits
// (16 bytes)
IAGCipheredData *cipheredData = [IAGAesGcm cipheredDataByAuthenticatedEncryptingPlainData:expectedPlainData
                                                          withAdditionalAuthenticatedData:aad
                                                                  authenticationTagLength:IAGAuthenticationTagLength128
                                                                     initializationVector:iv
                                                                                      key:key
                                                                                    error:nil];

// Authenticated Decryption Function
NSData *plainData = [IAGAesGcm plainDataByAuthenticatedDecryptingCipheredData:cipheredData
                                              withAdditionalAuthenticatedData:aad
                                                         initializationVector:iv
                                                                          key:key
                                                                        error:nil];

XCTAssertEqualObjects(expectedPlainData, plainData);

希望这段代码有任何帮助。

Hope this code is of any help.

要结束（并感谢 zaph 提及此），我没有对此代码执行任何基准测试，因此假设它是慢。我打算使用它来破译JWE字符串中的令牌，并且不时地，我不建议任何更多的要求。

To end (and thanks zaph for mentioning this), I have not performed any benchmarking of this code, so assume that it is slow. I intend to use it to decipher tokens in a JWE string and only from time to time, I do not recommend anything more requiring than that.

请问。

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