AES/CBC/PKCS7Padding 암복호화
까먹을까봐 기록. 결론은 구글링해서 얻은 결과 + 삽질.
Security.framework 를 사용. 아래 헤더 불러오기 등등.
#import <CommonCrypto/CommonCryptor.h>
CBC가 아니고 ECB모드 일 경우는 아래와 같이 수정을 하면 된다.
iv를 사용하면 CBC 모드가 된다.
kCCOptionECBMode + kCCOptionPKCS7Padding
Java에서는 PKCS5Padding 을 사용하는데 암복호화를 해보니 같은 데이터가 나오니까 같을지도...
- (NSData *)AES128EncryptWithKey:(NSData *)key theData:(NSData *)Data {
// '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 getBytes:keyPtr];
NSUInteger dataLength = [Data 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;
char ivPtr[16];
[_iv getBytes:ivPtr];
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding,
keyPtr,
kCCKeySizeAES128,
ivPtr, /* initialization vector (optional) */
[Data 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;
}
- (NSData *)AES128DecryptWithKey:(NSData *)key theData:(NSData *)Data {
// '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 getBytes:keyPtr];
NSUInteger dataLength = [Data 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);
char ivPtr[16];
[_iv getBytes:ivPtr];
size_t numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding,
keyPtr, kCCKeySizeAES128,
ivPtr /* initialization vector (optional) */,
[_decData bytes], dataLength, /* input */
buffer, bufferSize, /* output */
&numBytesDecrypted);
if (cryptStatus == kCCSuccess) {
//the returned NSData takes ownership of the buffer and will free it on deallocation
return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
}
free(buffer); //free the buffer;
return nil;
}