//
//  JHAES.m
//  测试
//
//  Created by CSDC on 2017/2/23.
//  Copyright © 2017年 jianhekeji. All rights reserved.
//

#import "JHAES.h"
#import <CommonCrypto/CommonCryptor.h>
#import "GTMBase64.h"

@implementation JHAES

+(NSString *)AES128Encrypt:(NSString *)plainText key:(NSString *)gkey iv:(NSString *)gIv{
    
    char keyPtr[kCCKeySizeAES128+1];
    bzero(keyPtr, sizeof(keyPtr));
    [gkey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    char ivPtr[kCCKeySizeAES128+1];
    memset(ivPtr, 0, sizeof(ivPtr));
    [gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

    NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [data length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesEncrypted = 0;
    //kCCOptionPKCS7Padding
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
                                          kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding,
                                          keyPtr,
                                          kCCBlockSizeAES128,
                                          ivPtr,
                                          [data bytes],
                                          dataLength,
                                          buffer,
                                          bufferSize,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        NSData *encryptedData = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
        return [self hexStringFromData:encryptedData];
    }
    free(buffer);
    return nil;
    

    
    
    
    
//    char keyPtr[kCCKeySizeAES128+1];
//    memset(keyPtr, 0, sizeof(keyPtr));
//    [gkey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
//
//    char ivPtr[kCCBlockSizeAES128+1];
//    memset(ivPtr, 0, sizeof(ivPtr));
//    [gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];
//
//    NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding];
//    int  dataLength = (int)[data length];
//    int diff = kCCKeySizeAES128 - (dataLength % kCCKeySizeAES128);
//    int newSize = 0;
//
//    if(diff > 0)
//    {
//        newSize = dataLength + diff;
//    }
//
//    char dataPtr[newSize];
//    memcpy(dataPtr, [data bytes], [data length]);
//    for(int i = 0; i < diff; i++)
//    {
//        dataPtr[i + dataLength] = 0x00;
//    }
//
//    size_t bufferSize = newSize + kCCBlockSizeAES128;
//    void *buffer = malloc(bufferSize);
//    memset(buffer, 0, bufferSize);
//
//    size_t numBytesCrypted = 0;
//    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
//                                          kCCAlgorithmAES128,
//                                          kCCOptionPKCS7Padding,
//                                          keyPtr,
//                                          kCCKeySizeAES128,
//                                          ivPtr,
//                                          dataPtr,
//                                          sizeof(dataPtr),
//                                          buffer,
//                                          bufferSize,
//                                          &numBytesCrypted);
//
//    if (cryptStatus == kCCSuccess) {
//        NSData *resultData = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];
//        return [GTMBase64 stringByEncodingData:resultData];
//    }
//    free(buffer);
//    return nil;
}

+ (NSString *)hexStringFromData:(NSData *)data {
    Byte *bytes = (Byte *)[data bytes];
    // 下面是Byte 转换为16进制。
    NSString *hexStr = @"";
    for(int i=0; i<[data length]; i++) {
        NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i] & 0xff]; //16进制数
        newHexStr = [newHexStr uppercaseString];
        
        if([newHexStr length] == 1) {
            newHexStr = [NSString stringWithFormat:@"0%@",newHexStr];
        }
        
        hexStr = [hexStr stringByAppendingString:newHexStr];
        
    }
    return hexStr;
}

+(NSString *)AES128Decrypt:(NSString *)encryptText key:(NSString *)gkey iv:(NSString *)gIv
{
    char keyPtr[kCCKeySizeAES128 + 1];
    memset(keyPtr, 0, sizeof(keyPtr));
    [gkey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    char ivPtr[kCCBlockSizeAES128 + 1];
    memset(ivPtr, 0, sizeof(ivPtr));
    [gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];
    
//    NSData *data = [GTMBase64 decodeData:[encryptText dataUsingEncoding:NSUTF8StringEncoding]];
    NSData *data = [self dataForHexString:encryptText];
    NSUInteger dataLength = [data length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    
    size_t numBytesCrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
                                          kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding,
                                          keyPtr,
                                          kCCBlockSizeAES128,
                                          ivPtr,
                                          [data bytes],
                                          dataLength,
                                          buffer,
                                          bufferSize,
                                          &numBytesCrypted);
    if (cryptStatus == kCCSuccess) {
        NSData *resultData = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];
        return [[NSString alloc] initWithData:resultData encoding:NSUTF8StringEncoding];
    }
    free(buffer);
    return nil;
}
+ (NSData*)dataForHexString:(NSString*)hexString
{
    if (hexString == nil) {
        return nil;
    }
    
    const char* ch = [[hexString lowercaseString] cStringUsingEncoding:NSUTF8StringEncoding];
    NSMutableData* data = [NSMutableData data];
    while (*ch) {
        if (*ch == ' ') {
            continue;
        }
        char byte = 0;
        if ('0' <= *ch && *ch <= '9') {
            
            byte = *ch - '0';
        }else if ('a' <= *ch && *ch <= 'f') {
            
            byte = *ch - 'a' + 10;
        }else if ('A' <= *ch && *ch <= 'F') {
            
            byte = *ch - 'A' + 10;
            
        }
        
        ch++;
        
        byte = byte << 4;
        
        if (*ch) {
            
            if ('0' <= *ch && *ch <= '9') {
                
                byte += *ch - '0';
                
            } else if ('a' <= *ch && *ch <= 'f') {
                
                byte += *ch - 'a' + 10;
                
            }else if('A' <= *ch && *ch <= 'F'){
                
                byte += *ch - 'A' + 10;
                
            }
            
            ch++;
            
        }
        
        [data appendBytes:&byte length:1];
        
    }
    
    return data;
}
@end