iOS AES加密

2016-06-13  本文已影响2218人  宁小缺

AES加密 

之前公司项目有需要用到这个加密,但是由于网络上找到的都是没有设置向量的,所以后来进行整理之后,自己写了个(虽然大部分是抄袭,请多指正)

1.下载GTM64,自己写太麻烦,本着腾讯精神,直接用别人的。

2.新建一个类别

类别

3.然后就是给里面添加方法了

.h文件中添加这几种方法

+(NSString *)AES128Encrypt:(NSString *)plainText withKey:(NSString *)key withIvStr:(NSString *)ivStr;

+(NSString *)processDecodedString:(NSString *)decoded;

+(NSString *)AES128Decrypt:(NSString *)encryptText withKey:(NSString *)key withIvStr:(NSString *)ivStr;

+(BOOL)validKey:(NSString*)key;

-(NSString *)processDecodedString:(NSString *)decoded;


.m文件中需要引入一下头文件 

#import "GTMBase64.h"

#import <CommonCrypto/CommonDigest.h>

#import <CommonCrypto/CommonCryptor.h>

下面就是方法的实现,key和向量都作为参数传入了,传入一个plainText,用一个字符串接返回值就OK啦,用起来十分方便。

+(NSString *)AES128Encrypt:(NSString *)plainText withKey:(NSString *)key withIvStr:(NSString *)ivStr

{

if(![self validKey:key] ){

return nil;

}

char keyPtr[kCCKeySizeAES128+1];

memset(keyPtr,0,sizeof(keyPtr));

[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

char ivPtr[kCCBlockSizeAES128+1];

memset(ivPtr,0,sizeof(ivPtr));

[key getCString:ivPtr maxLength:sizeof(ivPtr)encoding:NSUTF8StringEncoding];

NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding];

NSUInteger dataLength = [data length];

int diff = kCCKeySizeAES128-(dataLength%kCCKeySizeAES128);

unsigned long newSize = 0;

if(diff > 0)

{

newSize=dataLength+diff;

NSLog(@"diff is %d",diff);

}

char dataPtr[newSize];

memcpy(dataPtr,[data bytes], [data length]);

for(int i = 0; i < diff;i++)

{

dataPtr[i+dataLength] =0x0000;

}

size_t bufferSize =newSize+kCCBlockSizeAES128;

void *buffer = malloc(bufferSize);

memset(buffer,0,bufferSize);

size_t numBytesCrypted = 0;

//    NSString * new =[NSString stringWithFormat:@"n8fh3nFD955fe39J"]ini;

CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,

kCCAlgorithmAES128,

kCCOptionPKCS7Padding,

[key UTF8String],

kCCKeySizeAES128,

[ivStr UTF8String],

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 *)processDecodedString:(NSString *)decoded

{

if( decoded==nil || decoded.length==0 ){

return nil;

}

const char *tmpStr=[decoded UTF8String];

int i=0;

while( tmpStr[i]!='\0' )

{

i++;

}

NSString *final=[[NSString alloc]initWithBytes:tmpStr length:i encoding:NSUTF8StringEncoding];

return final;

}

+(NSString *)AES128Decrypt:(NSString *)encryptText withKey:(NSString *)key withIvStr:(NSString *)ivStr

{

if( ![self validKey:key] ){

return nil;

}

char keyPtr[kCCKeySizeAES128 + 1];

memset(keyPtr, 0, sizeof(keyPtr));

[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

char ivPtr[kCCBlockSizeAES128 + 1];

memset(ivPtr, 0, sizeof(ivPtr));

[key getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

NSData *data = [GTMBase64 decodeData:[encryptText dataUsingEncoding:NSUTF8StringEncoding]];

NSUInteger dataLength = [data length];

size_t bufferSize = dataLength + kCCBlockSizeAES128;

void *buffer = malloc(bufferSize);

size_t numBytesCrypted = 0;

CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,

kCCAlgorithmAES128,

kCCOptionPKCS7Padding,

[key UTF8String],

kCCBlockSizeAES128,

[ivStr UTF8String],

[data bytes],

dataLength,

buffer,

bufferSize,

&numBytesCrypted);

if (cryptStatus == kCCSuccess) {

NSData *resultData = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];

NSString *decoded=[[NSString alloc] initWithData:resultData encoding:NSUTF8StringEncoding];

return [self processDecodedString:decoded];

}

free(buffer);

return nil;

}

+(BOOL)validKey:(NSString*)key

{

if( key==nil || key.length !=16 ){

return NO;

}

return YES;

}

-(NSString *)processDecodedString:(NSString *)decoded

{

if( decoded==nil || decoded.length==0 ){

return nil;

}

const char *tmpStr=[decoded UTF8String];

int i=0;

while( tmpStr[i]!='\0' )

{

i++;

}

NSString *final=[[NSString alloc]initWithBytes:tmpStr length:i encoding:NSUTF8StringEncoding];

return final;

}

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