iOS 对称算法DES加解密

// // NSString+DES.m // test // // Created by 范云飞 on 2018/5/4. // Copyright © 2018年 范云飞. All rights reserved. //

#import "NSString+DES.h"

#import <CommonCrypto/CommonDigest.h>

#import <CommonCrypto/CommonCryptor.h>

@implementation NSString (DES)

• (NSData *)jm_hexStringConvertToBytesData { //异常字符串 if (self.length % 2 != 0) { return nil; }

  Byte bytes[1024*3] = {0};

  int bytesIndex = 0;

  for(int i = 0; i < [self length]; i++) {

    int int_char;  /// 两位16进制数转化后的10进制数
    
    unichar hex_charUpper = [self characterAtIndex:i]; ///两位16进制数中的第一位(高位*16)
    int int_charUpper;
    if(hex_charUpper >= '0' && hex_charUpper <='9') {
        int_charUpper = (hex_charUpper - 48 ) * 16;   // 0 的Ascll - 48
    } else if(hex_charUpper >= 'A' && hex_charUpper <= 'F') {
        int_charUpper = (hex_charUpper - 55 ) * 16; /// A 的Ascll - 65
    } else {
        int_charUpper = (hex_charUpper - 87 ) * 16; // a 的Ascll - 97
    }
    
    i++;
    
    unichar hex_charLower = [self characterAtIndex:i]; ///两位16进制数中的第二位(低位)
    int int_charLower;
    if(hex_charLower >= '0' && hex_charLower <= '9') {
        int_charLower = (hex_charLower - 48); /// 0 的Ascll - 48
    } else if(hex_charUpper >= 'A' && hex_charUpper <='F') {
        int_charLower = (hex_charLower - 55); ///  A 的Ascll - 65
    } else {
        int_charLower = hex_charLower - 87; /// a 的Ascll - 97
    }
    
    int_char = int_charUpper + int_charLower;
    bytes[bytesIndex] = int_char;  ///将转化后的数放入Byte数组里
    bytesIndex++;
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  }

  NSUInteger dataLength = self.length / 2;

  NSData *data = [[NSData alloc] initWithBytes:bytes length:dataLength];

  return data; }

• (NSString *)jm_urlDecode {

  NSString *decodedString = [self stringByRemovingPercentEncoding];

  return decodedString; }

• (NSString *)jm_urlEncode {

  NSString encodedString = [self stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet characterSetWithCharactersInString:@"!'();:@&=+$,/?%#[]"]];

  return encodedString; }

• (NSString *)jm_encryptUseDESByKey:(NSString *)key iv:(NSString *)iv { NSString *ciphertext; NSString *encode = [self jm_urlEncode]; // NSLog(@"%s encode::%@", func, encode);

  NSData *data = [encode dataUsingEncoding:NSUTF8StringEncoding];

  NSUInteger dataLength = data.length;

  NSUInteger bufferLength = 1024;

  unsigned char buffer[bufferLength];

  memset(buffer, 0, sizeof(char));

  size_t numBytesEncrypted = 0;

  CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES, kCCOptionPKCS7Padding, [key UTF8String], kCCKeySizeDES, [iv UTF8String] , //iv向量 [data bytes], dataLength, buffer, bufferLength, &numBytesEncrypted);

  if (cryptStatus == kCCSuccess) {

    NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
    //NSLog(@"%s buffer::%s", __func__, buffer);
    //NSLog(@"%s data::%@", __func__, data);
    
    ciphertext = @"";
    for (int index = 0; index < data.length; index++) {
        char byte;
        [data getBytes:&byte range:NSMakeRange(index, 1)];
        NSString *text = [NSString stringWithFormat:@"%x", byte&0xff];
        
        //不足两位，前面补0
        if([text length] == 1) {
            text = [NSString stringWithFormat:@"0%@", text];
        }
        
        ciphertext = [ciphertext stringByAppendingString:text];
    }
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  }

  NSLog(@"%s encryptText::%@", func, ciphertext); return ciphertext; }

• (NSString *)jm_decryptUseDesByKey:(NSString *)key iv:(NSString *)iv { NSString *decryptText;

  NSData *encryptData = [self jm_hexStringConvertToBytesData];

  const char *textBytes = [encryptData bytes];

  NSUInteger dataLength = encryptData.length;

  NSUInteger bufferLength = dataLength + 0x8 & 0xfffffff8;

  unsigned char buffer[bufferLength];

  memset(buffer, 0, sizeof(char));

  size_t numBytesEncrypted = 0;

  //将encryptText转化为bytes CCCryptorStatus decryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES, kCCOptionPKCS7Padding, [key UTF8String], kCCKeySizeDES, [iv UTF8String] , //iv向量 textBytes, dataLength, buffer, bufferLength, &numBytesEncrypted); if (decryptStatus == kCCSuccess ) {

    NSLog(@"%s buffer::%s", __func__, buffer);
    
    NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
    
    NSLog(@"%s data::%@", __func__, data);
    
    decryptText = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    NSLog(@"%s decryptText::%@", __func__, decryptText);
    
    decryptText = [decryptText jm_urlDecode];
    NSLog(@"%s decodeUrl::%@", __func__, decryptText);
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  }

  return decryptText; }

@end