AES接口加密

项目里有些时候需要用AES来进行接口加密，密钥分为固定密钥和动态密钥，一般固定密钥写死在app内，将登录的信息用固定密钥加密，放在登录的时候进行验证，验证通过后，会返回动态密钥，前端保存下来，调用加密接口时，用动态密钥进行加密。

首先是 AES 加密类（.h）：

#import 

@interface AES128 : NSObject

+(NSString *)AES128Encrypt:(NSString *)plainText key:(NSString *)key;//加密
+(NSString *)AES128Decrypt:(NSString *)encryptText key:(NSString *)key; //解密
@end

接着是 .m 文件

#import "AES128.h"
#import 

@implementation AES128

+( NSString *)AES128Encrypt:(NSString *)plainText key:(NSString *)key
{
    char keyPtr[kCCKeySizeAES128+1];
    memset(keyPtr, 0, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [data length];
    
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
                                          kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding|kCCOptionECBMode,
                                          keyPtr,
                                          kCCBlockSizeAES128,
                                          NULL,
                                          [data bytes],
                                          dataLength,
                                          buffer,
                                          bufferSize,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        // 对加密后的数据进行 base64 编码
        return [[NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted] base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithLineFeed];
    }
    free(buffer);
    return nil;
}

+ (NSString *)AES128Decrypt:(NSString *)encryptText key:(NSString *)key; //解密
{
    char keyPtr[kCCKeySizeAES128 + 1];
    memset(keyPtr, 0, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSData *data = [[NSData alloc] initWithBase64EncodedString:encryptText options:NSDataBase64DecodingIgnoreUnknownCharacters];
    NSUInteger dataLength = [data length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    
    size_t numBytesCrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
                                          kCCAlgorithmAES128,
                                          0x0000|kCCOptionECBMode|kCCOptionPKCS7Padding,
                                          keyPtr,
                                          kCCBlockSizeAES128,
                                          NULL,
                                          [data bytes],
                                          dataLength,
                                          buffer,
                                          bufferSize,
                                          &numBytesCrypted);
    if (cryptStatus == kCCSuccess) {
        return [[NSString alloc] initWithData:[NSData dataWithBytesNoCopy:buffer length:numBytesCrypted] encoding:NSUTF8StringEncoding];
    }
    free(buffer);
    return nil;
    
}
@end

接着就是需要加密的接口了，一般写在公共的网络请求类里，顺便说一下，一般加密接口都是 POST 请求，一般还需要带 token 请求头，设备信息等等，涉及到别的类，就不写进来了。

    // 创建会话管理者
    AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
    // 设置请求方式为 POST 并填入 url 地址（要对 url 处理，记得写在前面，不然给 url 加后缀没用）
    NSMutableURLRequest *request = [[AFHTTPRequestSerializer serializer] requestWithMethod:@"POST" URLString:url parameters:nil error:nil];

    // 判断要请求的接口是不是登录加密接口
    NSString *keyToken = @"";
    if ([url containsString:sign_in_phone_pass_URL] || [url containsString:sign_in_mail_pass_URL] || [url containsString:sign_up_phone_pass_URL] || [url containsString:sign_up_mail_pass_URL]) {
        // 是登录加密接口，使用固定密钥
        keyToken = KeyToken;
    }
    else {
        // 不是登录加密接口，使用保存在 userDeafult 的动态密钥
        keyToken = [UserInfoTool shareInstance].keyToken;
    }
    
    // 这句代码是把字典转 JSON 字符串，params 是你要传的参数字典
    NSString *str = [Utils convertToJsonData:params];

    // 将 JSON 字符串进行 AES 加密
    NSString *AesStr = [AES128 AES128Encrypt:str key:keyToken];
    // 设置接收格式
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    // 设置body
    [request setHTTPBody:[AesStr dataUsingEncoding:NSUTF8StringEncoding]];
    AFHTTPResponseSerializer *responseSerializer = [AFHTTPResponseSerializer serializer];
    responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"application/json",
                                                                      @"text/html",
                                                                      @"text/json",
                                                                      @"text/javascript",
                                                                      @"text/plain",
                                                                      nil];
    manager.responseSerializer = responseSerializer;
    
    // 需要使用 dataTask 的方式请求
    [[manager dataTaskWithRequest:request uploadProgress:^(NSProgress * _Nonnull uploadProgress) {
        
    } downloadProgress:^(NSProgress * _Nonnull downloadProgress) {
        
    } completionHandler:^(NSURLResponse * _Nonnull response, id  _Nullable responseObject, NSError * _Nullable error) {
        if (!error) {
            if (responseObject) {
                // 把返回对象转成 JSON，再转成字典
                id json = [self decrypeJsonWithData:responseObject];
                if ([json isKindOfClass:[NSDictionary class]]) {
                    NSDictionary *dic = (NSDictionary *)json;
                    // 把转化成功的字典回调出去
                    [self successWithData:dic success:success failure:failure];
                }
            }
        }
        else {
            errors(error);
            [self failureWithError:error];
        }
    }] resume];

- (id)decrypeJsonWithData:(NSData *)data {
    // 转成字符串
    NSString *jsonStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    // 转成json对象
    return [NSJSONSerialization JSONObjectWithData:[jsonStr dataUsingEncoding:NSUTF8StringEncoding] options:NSJSONReadingMutableContainers error:nil];
}