我不知道为什么原始mp3Data大小是4750347字节,而decryptData大小是4750344字节
TripleDES方法中是否存在任何实现错误?
谢谢你的回复。
- (void) testTripleDESMp3
{
NSString * mp3Path = [[self libraryPath]stringByAppendingPathComponent:@"A.mp3"];
NSData *mp3Data = [[NSData alloc] initWithContentsOfFile:mp3Path] ;//4750347
NSData *encryptData = [self TripleDES:mp3Data encryptOrDecrypt:kCCEncrypt key:@"12345"];//bufferPtrSize 4750352, plainTextBufferSize:4750347, movedBytes:47503520 ,NSData 6333804
NSData *decryptData = [self TripleDES:encryptData encryptOrDecrypt:kCCDecrypt key:@"12345"];//bufferPtrSize 4750360, plainTextBufferSize:4750352, movedBytes:4750344,NSData 4750344
//mp3Data 4750347 -> encryptData 6333804-> decryptData 4750344
NSError* error;
NSString * mp3Path2 = [[self libraryPath]stringByAppendingPathComponent:@"B.mp3"];
[decryptData writeToFile:mp3Path2 options:NSDataWritingAtomic error:&error];
}
- (NSData*)TripleDES:(NSData*)plainData encryptOrDecrypt:(CCOperation)encryptOrDecrypt key:(NSString*)key {
const void *vplainText;
size_t plainTextBufferSize;
if (encryptOrDecrypt == kCCDecrypt)
{
NSData *EncryptData = [GTMBase64 decodeData:plainData];
plainTextBufferSize = [EncryptData length];
vplainText = [EncryptData bytes];
}
else
{
plainTextBufferSize = [plainData length];
vplainText = (const void *)[plainData bytes];
}
CCCryptorStatus ccStatus;
//I am not sure use char*/void*/uint8_t
uint8_t *bufferPtr = NULL;
size_t bufferPtrSize = 0;
size_t movedBytes = 0;
bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
bufferPtr = static_cast<uint8_t *>(malloc( bufferPtrSize * sizeof(uint8_t)));
//bufferPtr = (char *)malloc( bufferPtrSize * sizeof(char));
memset((void *)bufferPtr, 0x0, bufferPtrSize);
// memset((void *) iv, 0x0, (size_t) sizeof(iv));
NSString *initVec = @"init Vec";
const void *vkey = (const void *) [key UTF8String];
const void *vinitVec = (const void *) [initVec UTF8String];
ccStatus = CCCrypt(encryptOrDecrypt,
kCCAlgorithm3DES,
kCCOptionPKCS7Padding,//kCCOptionECBMode,
vkey,
kCCKeySize3DES,
vinitVec, //"init Vec", //iv,
vplainText, //"Your Name", //plainText,
plainTextBufferSize,
(void *)bufferPtr,
bufferPtrSize,
&movedBytes);
if (ccStatus == kCCSuccess) NSLog(@"SUCCESS");
else if (ccStatus == kCCParamError) NSLog( @"PARAM ERROR");
else if (ccStatus == kCCBufferTooSmall) NSLog( @"BUFFER TOO SMALL");
else if (ccStatus == kCCMemoryFailure) NSLog( @"MEMORY FAILURE");
else if (ccStatus == kCCAlignmentError) NSLog( @"ALIGNMENT");
else if (ccStatus == kCCDecodeError) NSLog( @"DECODE ERROR");
else if (ccStatus == kCCUnimplemented) NSLog( @"UNIMPLEMENTED");
NSData *result;
if (encryptOrDecrypt == kCCDecrypt)
{
result = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];
}
else
{
NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];
result = [GTMBase64 encodeData:myData];
}
//bufferPtrSize 1931240, plainTextBufferSize:1931232, movedBytes:1931232
NSLog(@"bufferPtrSize %d, plainTextBufferSize:%d, movedBytes:%d", (int)bufferPtrSize,(int)plainTextBufferSize, (int)movedBytes);//
return result;
}