Objective-C AES加解密

在线加解密：https://blog.zhengxianjun.com/online-tool/crypto/aes/
一、AES简介
高级加密标准（英语：Advanced Encryption Standard，缩写：AES），在密码学中又称Rijndael加密法。AES是一个对称分组密码算法，旨在取代DES成为广泛使用的标准。根据使用的密码长度，AES最常见的有3种方案，用以适应不同的场景要求，分别是AES-128、AES-192和AES-256。
二、算法描述
AES1
AES2
=AES算法较为复杂这里不再赘述，如有兴趣可点击描述出处查看更多资料。
三、算法实现
@implementation CATSecurity#pragma mark --#pragma mark -- AES/** *  get data's aes256 encrypt data * *  @param data source data *  @param key  key for encrypt/decrypt  !!!key length must be 16 * *  @return aes256 encrypt data */+(NSData *)aes256EncryptWithData:(NSData *)data key:(NSString *)key{    if (!key || key.length !=16) {        NSLog(@"key length must be 16");        return nil;    }    char keyPtr[kCCKeySizeAES256+1];    bzero(keyPtr, sizeof(keyPtr));    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding: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) {        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];    }    free(buffer);    return nil;}/** *  get source data from aes256 encrypt data * *  @param data aes256 encrypt data *  @param key  key for encrypt/decrypt  !!!key length must be 16 * *  @return source data */+(NSData *)aes256DecryptWithData:(NSData *)data key:(NSString *)key{    if (!key || key.length !=16) {        NSLog(@"key length must be 16");        return nil;    }    char keyPtr[kCCKeySizeAES256+1];    bzero(keyPtr, sizeof(keyPtr));    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];    NSUInteger dataLength = data.length;    size_t bufferSize = dataLength + kCCBlockSizeAES128;    void *buffer = malloc(bufferSize);    size_t numBytesDecrypted = 0;    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128,                                          kCCOptionPKCS7Padding | kCCOptionECBMode,                                          keyPtr, kCCBlockSizeAES128,                                          NULL,                                          data.bytes, dataLength,                                          buffer, bufferSize,                                          &numBytesDecrypted);    if (cryptStatus == kCCSuccess) {        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];    }    free(buffer);    return nil;}/** *  get string's aes256 encrypt data * *  @param string source string *  @param key  key for encrypt/decrypt  !!!key length must be 16 * *  @return aes256 encrypt data */+(NSData*)aes256EncryptWithString:(NSString*)string key:(NSString *)key{    if (!key || key.length !=16) {        NSLog(@"key length must be 16");        return nil;    }    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];    NSData *encryptedData = [self aes256EncryptWithData:data key:key];    return encryptedData;}/** *  get source string from aes256 encrypt data * *  @param data aes256 encrypt data *  @param key  key for encrypt/decrypt  !!!key length must be 16 * *  @return source string */+(NSString*)aes256DecryptStringWithData:(NSData *)data key:(NSString *)key{    if (!key || key.length !=16) {        NSLog(@"key length must be 16");        return nil;    }    NSData *decryData = [self aes256DecryptWithData:data key:key];    NSString *string = [[NSString alloc] initWithData:decryData encoding:NSUTF8StringEncoding];    return string;}@end
四、补充
由于iOS、java的平台差异，AES的加密算法存在兼容性问题(iOS的AES Padding只支持ccPKCS7Padding, ccNoPadding)，为了使用方便，我找了一份可兼容的Java的代码并做了测试，详见工程的java目录。


作者：CatchZeng
链接：http://www.jianshu.com/p/1247e946c61f
來源：简书
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