本文介绍了iOS加密AES128 / CBC / nopadding为什么不工作？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个应用程序需要使用AES / CBC /无填充编码一些数据。该应用程序也在Android上移植。编码完成如下： byte [] encodedKey = getKey（）;
SecretKeySpec skeySpec = new SecretKeySpec（encodedKey，AES）;
AlgorithmParameterSpec paramSpec = new IvParameterSpec（initializationVector）;
密码密码= Cipher.getInstance（AES / CBC / NoPadding）;
cipher.init（Cipher.ENCRYPT_MODE，skeySpec，paramSpec）;
int blockSize = cipher.getBlockSize（）;
int diffSize = decryptpted.length％blockSize;
System.out.println（Cipher size：+ blockSize）;
System.out.println（当前大小：+ decryptpted.length）;
if（diffSize！= 0）{
diffSize = blockSize - diffSize;
byte [] oldDecrypted =解密;
decryptpted = new byte [decryptpted.length + diffSize];
System.arraycopy（oldDecrypted，0，decryptpted，0，oldDecrypted.length）; （int i = 0; i< diffSize; i ++）{
decrypted [i + oldDecrypted.length] =.getBytes（）[0];
}
System.out.println（New size：+ decryptpted.length）;
}
返回cipher.doFinal（解密）;
初始化视图如下所示：
private byte [] initialVector = new byte [] {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00， 0x00};在iOS上有
$ b $ （NSData *）AES128EncryptWithKey：（NSString *）键
{
//'key'应为AES128的16个字节，将为null-填充否则
char keyPtr [kCCKeySizeAES128 + 1]; //用于终结器的空间（未使用）
bzero（keyPtr，sizeof（keyPtr））; //填充零（用于填充）
//获取密钥数据
[key getCString：keyPtr maxLength：sizeof（keyPtr）encoding：NSUTF8StringEncoding];
NSUInteger dataLength = [self length];
//查看文档：对于块密码，输出大小始终小于或等于输入大小加上一个块的大小。
//这就是为什么我们需要在这里添加一个块的大小
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void * buffer = malloc（bufferSize）;
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt（kCCEncrypt，
kCCAlgorithmAES128，
0x0000，
keyPtr，
kCCKeySizeAES128，
NULL / *初始化向量（可选）* /
[self bytes]，dataLength，/ * input * /
buffer，bufferSize，/ * output * /
& numBytesEncrypted）;
if（cryptStatus == kCCSuccess）{
//返回的NSData获取缓冲区的所有权，并在释放后释放它
return [NSData dataWithBytesNoCopy：buffer length：numBytesEncrypted];
}
free（buffer）; //释放缓冲区;
return nil;
}
上述方法是NSData类别的一部分。
该方法被调用如下：
NSData * data = [@4915200456727dataUsingEncoding：NSUTF8StringEncoding];
NSData * cipher = [data AES128EncryptWithKey：@@ x＃zddXekZerBBw6];
NSString * ecriptedString = [NSString stringWithFormat：@％。* s，[cipher length]，[cipher bytes]];
我的问题是我在iOS和Android上没有收到相同的加密数据。在iOS上，加密数据的长度为0字节。
可以给出任何关于如何使用AES128和CBC加密字符串的指针，也可以是一个例子？
谢谢
解决方案
我找到了解决问题的办法。为了使加密工作没有填充，我不得不添加0x0000而不是kCCOptionPKCS7Padding或kCCOptionECBMode被处理。
另外，如果需要编码的数据不具有kCCKeySizeAES128（16）的长度倍数，那么保存数据的向量必须被调整为具有kCCKeySizeAES128的长度倍数，并且填充一些空值。我添加了空格。
- （NSData *）AES128EncryptWithKey :( NSString *）键
{
char keyPtr [kCCKeySizeAES128 + 1];
bzero（keyPtr，sizeof（keyPtr））;
[key getCString：keyPtr maxLength：sizeof（keyPtr）encoding：NSUTF8StringEncoding];
int dataLength = [self length];
int diff = kCCKeySizeAES128 - （dataLength％kCCKeySizeAES128）;
int newSize = 0;
if（diff> 0）
{
newSize = dataLength + diff;
}
char dataPtr [newSize];
memcpy（dataPtr，[self bytes]，[self length]）; （int i = 0; i< diff; i ++）
{
dataPtr [i + dataLength] = 0x20;
}
size_t bufferSize = newSize + kCCBlockSizeAES128;
void * buffer = malloc（bufferSize）;
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt（kCCEncrypt，
kCCAlgorithmAES128，
0x0000，//无填充
keyPtr，
kCCKeySizeAES128，
NULL，
dataPtr ，
sizeof（dataPtr），
buffer，
bufferSize，
& numBytesEncrypted）;
if（cryptStatus == kCCSuccess）
{
return [NSData dataWithBytesNoCopy：buffer length：numBytesEncrypted];
}
return nil;
}
I have an app that needs to encode some data using AES/CBC/no padding. The app is ported also on android. There the encoding is done like this:
byte[] encodedKey = getKey();
SecretKeySpec skeySpec = new SecretKeySpec(encodedKey, "AES");
AlgorithmParameterSpec paramSpec = new IvParameterSpec(initializationVector);
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, paramSpec);
int blockSize = cipher.getBlockSize();
int diffSize = decrypted.length % blockSize;
System.out.println("Cipher size: " + blockSize);
System.out.println("Current size: " + decrypted.length);
if (diffSize != 0) {
diffSize = blockSize - diffSize;
byte[] oldDecrypted = decrypted;
decrypted = new byte[decrypted.length + diffSize];
System.arraycopy(oldDecrypted, 0, decrypted, 0, oldDecrypted.length);
for (int i = 0; i < diffSize; i++) {
decrypted[i + oldDecrypted.length] = " ".getBytes()[0];
}
System.out.println("New size: " + decrypted.length);
}
return cipher.doFinal(decrypted);
the initializationVector looks like this:
private byte[] initializationVector = new byte[] { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
on iOS i have something like this for encryption:
- (NSData *)AES128EncryptWithKey:(NSString *)key
{
// 'key' should be 16 bytes for AES128, will be null-padded otherwise
char keyPtr[kCCKeySizeAES128+1]; // room for terminator (unused)
bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
// fetch key data
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
NSUInteger dataLength = [self length];
//See the doc: For block ciphers, the output size will always be less than or
//equal to the input size plus the size of one block.
//That's why we need to add the size of one block here
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmAES128,
0x0000,
keyPtr,
kCCKeySizeAES128,
NULL /* initialization vector (optional) */,
[self bytes], dataLength, /* input */
buffer, bufferSize, /* output */
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
//the returned NSData takes ownership of the buffer and will free it on deallocation
return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}
free(buffer); //free the buffer;
return nil;
}
the method described above is part of a category over NSData.the method is called like this:
NSData *data = [@"4915200456727" dataUsingEncoding:NSUTF8StringEncoding];
NSData *cipher = [data AES128EncryptWithKey:@"@x#zddXekZerBBw6"];
NSString *ecriptedString = [NSString stringWithFormat:@"%.*s", [cipher length], [cipher bytes]];
the problem that i have is that i don't receive the same encrypted data on iOS and android. On iOS the encrypted data has 0 bytes in length.
Could you give any pointers on how to encrypt a string using AES128 with CBC and no padding and perhaps an example?
Thank you
解决方案
I found the solution to my problem. In order to make the encryption work without padding i had to add 0x0000 instead of kCCOptionPKCS7Padding or kCCOptionECBMode which are treated.
Also if the data that needs to be encoded doesn't have a length multiple of kCCKeySizeAES128 ( 16 ) then the vector that holds the data must be resized to have the length multiple with kCCKeySizeAES128 and the empty values filled with something. I added spaces.
- (NSData *)AES128EncryptWithKey:(NSString *)key
{
char keyPtr[kCCKeySizeAES128+1];
bzero(keyPtr, sizeof(keyPtr));
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
int dataLength = [self length];
int diff = kCCKeySizeAES128 - (dataLength % kCCKeySizeAES128);
int newSize = 0;
if(diff > 0)
{
newSize = dataLength + diff;
}
char dataPtr[newSize];
memcpy(dataPtr, [self bytes], [self length]);
for(int i = 0; i < diff; i++)
{
dataPtr[i + dataLength] = 0x20;
}
size_t bufferSize = newSize + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmAES128,
0x0000, //No padding
keyPtr,
kCCKeySizeAES128,
NULL,
dataPtr,
sizeof(dataPtr),
buffer,
bufferSize,
&numBytesEncrypted);
if(cryptStatus == kCCSuccess)
{
return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}
return nil;
}
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