iOS開發之Objective-c的AES加密和解密演算法的實現

標籤：

進階加密標準（Advanced Encryption Standard，AES），又稱Rijndael加密法。 以下實現代碼中分別為NSData和NSString增加了一個Category。使用時直接調用即可。 

需要注意的是，AES並不能作為HASH演算法，加密並解密後的結果，並不一定與原文相同，使用時請注意進行結果驗算。例如解密原文的長度，格式規則等。 NG執行個體 

原文：170987350密碼：170

Objective-c的AES加密和解密演算法的具體實現代碼如下： 1.拓展NSData，增加AES256加密方法 

////NSData+AES256.h// #import <Foundation/Foundation.h>#import <CommonCrypto/CommonDigest.h>#import <CommonCrypto/CommonCryptor.h> @interface NSData(AES256)-(NSData *) aes256_encrypt:(NSString *)key;-(NSData *) aes256_decrypt:(NSString *)key;@end ////NSData+AES256.m//#import "NSData+AES256.h" @implementation NSData(AES256) - (NSData *)aes256_encrypt:(NSString *)key //加密{ char keyPtr[kCCKeySizeAES256+1]; bzero(keyPtr, sizeof(keyPtr)); [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding]; NSUInteger dataLength = [self length]; size_t bufferSize = dataLength + kCCBlockSizeAES128; void *buffer = malloc(bufferSize); size_t numBytesEncrypted = 0; CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding | kCCOptionECBMode, keyPtr, kCCBlockSizeAES128, NULL, [self bytes], dataLength, buffer, bufferSize, &numBytesEncrypted); if (cryptStatus == kCCSuccess) { return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted]; } free(buffer); return nil;} - (NSData *)aes256_decrypt:(NSString *)key //解密{ char keyPtr[kCCKeySizeAES256+1]; bzero(keyPtr, sizeof(keyPtr)); [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding]; NSUInteger dataLength = [self length]; size_t bufferSize = dataLength + kCCBlockSizeAES128; void *buffer = malloc(bufferSize); size_t numBytesDecrypted = 0; CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding | kCCOptionECBMode, keyPtr, kCCBlockSizeAES128, NULL, [self bytes], dataLength, buffer, bufferSize, &numBytesDecrypted); if (cryptStatus == kCCSuccess) { return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted]; } free(buffer); return nil;}@end

2.拓展NSString，增加AES256加密方法，需要匯入NSData+AES256.h

////NSString +AES256.h// #import <Foundation/Foundation.h>#import <CommonCrypto/CommonDigest.h>#import <CommonCrypto/CommonCryptor.h> #import "NSData+AES256.h" @interface NSString(AES256) -(NSString *) aes256_encrypt:(NSString *)key;-(NSString *) aes256_decrypt:(NSString *)key; @end ////NSString +AES256.h// @implementation NSString(AES256) -(NSString *) aes256_encrypt:(NSString *)key{ const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding]; NSData *data = [NSData dataWithBytes:cstr length:self.length]; //對資料進行加密 NSData *result = [data aes256_encrypt:key]; //轉換為2進位字串 if (result && result.length > 0) { Byte *datas = (Byte*)[result bytes]; NSMutableString *output = [NSMutableString stringWithCapacity:result.length * 2]; for(int i = 0; i < result.length; i++){ [output appendFormat:@"%02x", datas[i]]; } return output; } return nil;} -(NSString *) aes256_decrypt:(NSString *)key{ //轉換為2進位Data NSMutableData *data = [NSMutableData dataWithCapacity:self.length / 2]; unsigned char whole_byte; char byte_chars[3] = {‘\0‘,‘\0‘,‘\0‘}; int i; for (i=0; i < [self length] / 2; i++) { byte_chars[0] = [self characterAtIndex:i*2]; byte_chars[1] = [self characterAtIndex:i*2+1]; whole_byte = strtol(byte_chars, NULL, 16); [data appendBytes:&whole_byte length:1]; } //對資料進行解密 NSData* result = [data aes256_decrypt:key]; if (result && result.length > 0) { return [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding]autorelease]; } return nil;}@end

 

iOS開發之Objective-c的AES加密和解密演算法的實現