#import "escryptor.h"

#import "b64.h"

#include <openssl/aes.h>

@implementation escryptor

extern int OPENSSL_cleanse(void *ptr, size_t len);

+(NSData *)encryptNSData:(NSString*)key :(NSData*)data {

//add padding

int padlen = AES_BLOCK_SIZE - (data.length % AES_BLOCK_SIZE);

NSMutableData *paddedData = [[NSMutableData data] initWithData:data];

for (int i = 0; i < padlen; i++) {

char bytesToAppend[1] = {(char)padlen};

[paddedData appendBytes:bytesToAppend length:1];

}

const unsigned char* aeskey = (const unsigned char*)[key cStringUsingEncoding:NSASCIIStringEncoding];

OPENSSL_cleanse(NULL, 0);

/* Initialization vector */

unsigned char iv[AES_BLOCK_SIZE];

//outputbuffer

unsigned char *output = (unsigned char *)malloc(data.length * sizeof(char));

/* AES-128 bit CBC Encryption */

AES_KEY enc_key;

//encrypt

memset(iv, 0, AES_BLOCK_SIZE);

AES_set_encrypt_key(aeskey, (int)strlen((const char*)aeskey) * 8, &enc_key);

//input, output, inputlength, key, iv, operation

AES_cbc_encrypt([paddedData bytes], output, paddedData.length, &enc_key, iv, AES_ENCRYPT);

NSData *finalData = [NSData dataWithBytes:output length:paddedData.length];

return finalData;

}

+(NSData *)decryptNSData:(NSString*)key :(NSData*)data {

//work around to find length, strlen won't count size after \0

//init args

const unsigned char* aeskey = (const unsigned char*)[key cStringUsingEncoding:NSASCIIStringEncoding];

//cleanse your soul

OPENSSL_cleanse(NULL, 0);

/* Initialization vector */

unsigned char iv[AES_BLOCK_SIZE];

//outputbuffer

unsigned char *output = (unsigned char *)malloc(data.length * sizeof(char));

/* AES-128 bit CBC Encryption */

memset(iv, 0, AES_BLOCK_SIZE);

AES_KEY dec_key;

//decrypt

AES_set_decrypt_key(aeskey, (int)strlen((const char*)aeskey) * 8, &dec_key);

//DECRYPT! input, output, inputlength, key, iv, operation

AES_cbc_encrypt([data bytes], output, data.length, &dec_key, iv, AES_DECRYPT);

//const char to nsdata, substring from our blocksize total

//NSData *outputData;

//remove padding, detect if last byte is a padding byte

int padnum = (char)output[(int)data.length - 1];

//if nothing to unpad

if (padnum > 16) {

padnum = 0;

}

//complete

NSData *finalData = [NSData dataWithBytes:output length:(int)data.length - padnum];

return finalData;

}

+(NSString *)encryptNSStringToB64:(NSString*)key :(NSString*)data {

//add padding

int padlen = AES_BLOCK_SIZE - (data.length % AES_BLOCK_SIZE);

for (int i = 0; i < padlen; i++) {

data = [NSString stringWithFormat:@"%@%c",data,(char)padlen]; //need right formatting

}

const unsigned char* inputdata = (const unsigned char*)[data cStringUsingEncoding:NSASCIIStringEncoding];

const unsigned char* aeskey = (const unsigned char*)[key cStringUsingEncoding:NSASCIIStringEncoding];

OPENSSL_cleanse(NULL, 0);

/* Initialization vector */

unsigned char iv[AES_BLOCK_SIZE];

//outputbuffer

unsigned char output[strlen((const char*)inputdata)];

/* AES-128 bit CBC Encryption */

AES_KEY enc_key;

//encrypt

memset(iv, 0, AES_BLOCK_SIZE);

AES_set_encrypt_key(aeskey, (int)strlen((const char*)aeskey) * 8, &enc_key);

//input, output, inputlength, key, iv, operation

AES_cbc_encrypt(inputdata, output, strlen((const char*)inputdata), &enc_key, iv, AES_ENCRYPT);

//decrypt

return [NSString stringWithFormat:@"%s",b64_encode(output, strlen((const char*)inputdata))];

}

+(NSString *)decryptB64ToNSString:(NSString*)key :(NSString*)data {

//work around to find length, strlen won't count size after \0

size_t outputlen = [[NSData alloc] initWithBase64EncodedString:data options:0].length;

//init args

const unsigned char* inputdata = b64_decode([data cStringUsingEncoding:NSASCIIStringEncoding],data.length);

const unsigned char* aeskey = (const unsigned char*)[key cStringUsingEncoding:NSASCIIStringEncoding];

//cleanse your soul

OPENSSL_cleanse(NULL, 0);

/* Initialization vector */

unsigned char iv[AES_BLOCK_SIZE];

//outputbuffer

unsigned char output[outputlen];

/* AES-128 bit CBC Encryption */

memset(iv, 0, AES_BLOCK_SIZE);

AES_KEY dec_key;

//decrypt

AES_set_decrypt_key(aeskey, (int)strlen((const char*)aeskey) * 8, &dec_key);

//DECRYPT! input, output, inputlength, key, iv, operation

AES_cbc_encrypt(inputdata, output, outputlen, &dec_key, iv, AES_DECRYPT);

//const char to nsstring, substring from our blocksize total

NSString *outputString = [[NSString stringWithCString:(const char *)output encoding:NSASCIIStringEncoding] substringToIndex:outputlen];

//remove padding, detect if last byte is a padding byte

int padnum = (char)output[(int)outputlen - 1];

if (padnum <= 16) {

//trim

outputString = [outputString substringToIndex:outputString.length - padnum];

}

//complete

return outputString;

}