如何解密基64編碼的值

Question

我新在iphone development.I正在使用

-(NSString *)Base64Encode:(NSData *)data 
{ 
    //Point to start of the data and set buffer sizes 
    int inLength = [data length]; 
    int outLength = ((((inLength * 4)/3)/4)*4) + (((inLength * 4)/3)%4 ? 4 : 0); 
    const char *inputBuffer = [data bytes]; 
    char *outputBuffer = malloc(outLength); 
    outputBuffer[outLength] = 0; 
    //64 digit code 
    static char Encode[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/"; 
    //start the count 
    int cycle = 0; 
    int inpos = 0; 
    int outpos = 0; 
    char temp; 
    //Pad the last to bytes, the outbuffer must always be a multiple of 4 
    outputBuffer[outLength-1] = '='; 
    outputBuffer[outLength-2] = '='; 

    while (inpos < inLength) 
    {  switch (cycle) 
     {   case 0:   
      outputBuffer[outpos++] = Encode[(inputBuffer[inpos]&0xFC)>>2];  
      cycle = 1;    
      break;   
     case 1:    
      temp = (inputBuffer[inpos++]&0x03)<<4; 
      outputBuffer[outpos] = Encode[temp];  
      cycle = 2;  
      break;   
     case 2:   
      outputBuffer[outpos++] = Encode[temp|(inputBuffer[inpos]&0xF0)>> 4];  
      temp = (inputBuffer[inpos++]&0x0F)<<2; 
      outputBuffer[outpos] = Encode[temp]; 
      cycle = 3;        
      break;  
     case 3:  
      outputBuffer[outpos++] = Encode[temp|(inputBuffer[inpos]&0xC0)>>6]; 
      cycle = 4;  
      break;  
     case 4:   
      outputBuffer[outpos++] = Encode[inputBuffer[inpos++]&0x3f]; 
      cycle = 0; 
      break; 
     default: 
      cycle = 0; 
      break;  
     } 
    } 
    NSString *pictemp = [NSString stringWithUTF8String:outputBuffer]; 
    free(outputBuffer); 
    return pictemp; 
} 

此代碼爲數據的加密，這是這是我也使用在我的Java代碼邏輯。但我不知道如何在這個加密結果方法的目標c中編寫解密邏輯。是否有人有想法，請幫助我。感謝您提前！

Answer 1

結賬http://cocoawithlove.com/2009/06/base64-encoding-options-on-mac-and.html Ag是Objective-C程序員的博客！