iOS中的AES256算法-白红宇

这次只展示代码，算法原理，网上一堆，我就不介绍了。

#import "Helper.h"#import 
    
     #import 
     
      #import "TDWBase64.h"@implementation Helper///加密+ (NSString *)aes256EncrytWithContent:(NSString *)content key:(NSString *)key {        NSData *contentData = [content dataUsingEncoding:NSUTF8StringEncoding];    char keyptr[kCCKeySizeAES256+1];    bzero(keyptr, sizeof(keyptr));    [key getCString:keyptr maxLength:sizeof(keyptr) encoding:NSUTF8StringEncoding];    NSUInteger datalength = contentData.length;    size_t bufferSize = datalength + kCCBlockSizeAES128;    void *buffer = malloc(bufferSize);    size_t numBytesEncrypted = 0;        char iv[] = {0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x38};        CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyptr, 32, iv, contentData.bytes, datalength, buffer, bufferSize, &numBytesEncrypted);        if (cryptStatus == kCCSuccess) {                NSData *data = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];        NSString *result = [TDWBase64 stringByEncodingData:data];        return result;            } else {                free(buffer);        return nil;    }        return @"";}///解密+ (NSString *)aes256DecrytWithContent:(NSString *)content key:(NSString *)key {        NSData *contentData = [TDWBase64 decodeString:content];    char keyptr[kCCKeySizeAES256+1];    bzero(keyptr, sizeof(keyptr));    [key getCString:keyptr maxLength:sizeof(keyptr) encoding:NSUTF8StringEncoding];    NSUInteger datalength = contentData.length;    size_t bufferSize = datalength + kCCBlockSizeAES128;    void *buffer = malloc(bufferSize);    size_t numBytesEncrypted = 0;        char iv[] = {0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x30, 0x31, 0x30, 0x38};        CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyptr, 32, iv, contentData.bytes, datalength, buffer, bufferSize, &numBytesEncrypted);        if (cryptStatus == kCCSuccess) {                NSData *data = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];        NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];        return result;            } else {                free(buffer);        return nil;    }        return @"";}复制代码

坑点： 1.

NSData *data = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];复制代码

这个会自动释放buffer。坑点文章：

2.Vi偏移量要用byte的形式写。