算法具体实现没有研究,使用关键是要保证加密和解密能够匹配上，而且要app和后台匹配上，才能够使用加密后的数据通信。
1、AES128：
AES128是需要一个初始化向量iv的，和256不一样。
//加密
- (NSData *)AES128EncryptWithKey:(NSString *)key iv:(NSString *)iv
{
return [self AES128Operation:kCCEncrypt key:key iv:iv];
}
//解密
- (NSData *)AES128DecryptWithKey:(NSString *)key iv:(NSString *)iv
{
return [self AES128Operation:kCCDecrypt key:key iv:iv];
}
//调用方法
- (NSData *)AES128Operation:(CCOperation)operation key:(NSString *)key iv:(NSString *)iv
{
char keyPtr[kCCKeySizeAES128 + 1];
memset(keyPtr, 0, sizeof(keyPtr));
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
char ivPtr[kCCBlockSizeAES128 + 1];
memset(ivPtr, 0, sizeof(ivPtr));
[iv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];
NSUInteger dataLength = [self length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesCrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(operation,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding,
keyPtr,
kCCBlockSizeAES128,
ivPtr,
[self bytes],
dataLength,
buffer,
bufferSize,
&numBytesCrypted);
if (cryptStatus == kCCSuccess) {
return [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];
}
free(buffer);
return nil;
}
2、AES256:
- (NSData *)AES256EncryptWithKey:(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 *)AES256DecryptWithKey:(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;
}