This is the code I am using for the encryption but it generate an error
"CCKeyDerivationPBKDF is unavailable" in AESKeyForPassword method though it is declare before implementation. How to Resolve it.
#ifndef _CC_PBKDF_H_
#define _CC_PBKDF_H_
#include <sys/types.h>
#include <sys/param.h>
#include <string.h>
#include <limits.h>
#include <stdlib.h>
#include <Availability.h>
#include <CommonCrypto/CommonDigest.h>
#include <CommonCrypto/CommonHMAC.h>
#ifdef __cplusplus
extern "C" {
#endif
enum {
kCCPBKDF2 = 2,
};
typedef uint32_t CCPBKDFAlgorithm;
enum {
kCCPRFHmacAlgSHA1 = 1,
kCCPRFHmacAlgSHA224 = 2,
kCCPRFHmacAlgSHA256 = 3,
kCCPRFHmacAlgSHA384 = 4,
kCCPRFHmacAlgSHA512 = 5,
};
typedef uint32_t CCPseudoRandomAlgorithm;
/*
@function CCKeyDerivationPBKDF
@abstract Derive a key from a text password/passphrase
@param algorithm Currently only PBKDF2 is available via kCCPBKDF2
@param password The text password used as input to the derivation
function. The actual octets present in this string
will be used with no additional processing. It's
extremely important that the same encoding and
normalization be used each time this routine is
called if the same key is expected to be derived.
@param passwordLen The length of the text password in bytes.
@param salt The salt byte values used as input to the derivation
function.
@param saltLen The length of the salt in bytes.
@param prf The Pseudo Random Algorithm to use for the derivation
iterations.
@param rounds The number of rounds of the Pseudo Random Algorithm
to use.
@param derivedKey The resulting derived key produced by the function.
The space for this must be provided by the caller.
@param derivedKeyLen The expected length of the derived key in bytes.
@discussion The following values are used to designate the PRF:
* kCCPRFHmacAlgSHA1
* kCCPRFHmacAlgSHA224
* kCCPRFHmacAlgSHA256
* kCCPRFHmacAlgSHA384
* kCCPRFHmacAlgSHA512
@result kCCParamError can result from bad values for the password, salt,
and unwrapped key pointers as well as a bad value for the prf function.
*/
int CCKeyDerivationPBKDF( CCPBKDFAlgorithm algorithm, const char *password, size_t passwordLen,
const uint8_t *salt, size_t saltLen,
CCPseudoRandomAlgorithm prf, uint rounds,
uint8_t *derivedKey, size_t derivedKeyLen)
__OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
/*
* All lengths are in bytes - not bits.
*/
/*
@function CCCalibratePBKDF
@abstract Determine the number of PRF rounds to use for a specific delay on
the current platform.
@param algorithm Currently only PBKDF2 is available via kCCPBKDF2
@param passwordLen The length of the text password in bytes.
@param saltLen The length of the salt in bytes.
@param prf The Pseudo Random Algorithm to use for the derivation
iterations.
@param derivedKeyLen The expected length of the derived key in bytes.
@param msec The targetted duration we want to achieve for a key
derivation with these parameters.
@result the number of iterations to use for the desired processing time.
*/
uint CCCalibratePBKDF(CCPBKDFAlgorithm algorithm, size_t passwordLen, size_t saltLen,
CCPseudoRandomAlgorithm prf, size_t derivedKeyLen, uint32_t msec)
__OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
#ifdef __cplusplus
}
#endif
#endif /* _CC_PBKDF_H_ */
#import "AESEncryption.h"
#import <CommonCrypto/CommonCryptor.h>
//#import <CommonCrypto/CommonKeyDerivation.h>
//#import <CommonKeyDerivation.h>
@implementation AESEncryption
NSString * const
kRNCryptManagerErrorDomain = @"net.robnapier.RNCryptManager";
const CCAlgorithm kAlgorithm = kCCAlgorithmAES128;
const NSUInteger kAlgorithmKeySize = kCCKeySizeAES128;
const NSUInteger kAlgorithmBlockSize = kCCBlockSizeAES128;
const NSUInteger kAlgorithmIVSize = kCCBlockSizeAES128;
const NSUInteger kPBKDFSaltSize = 8;
const NSUInteger kPBKDFRounds = 1000;//0; // ~80ms on an iPhone 4
// ===================
+ (NSData *)encryptedDataForData:(NSData *)data
password:(NSString *)password
iv:(NSData **)iv
salt:(NSData **)salt
error:(NSError **)error {
NSAssert(iv, @"IV must not be NULL");
NSAssert(salt, @"salt must not be NULL");
*iv = [self randomDataOfLength:kAlgorithmIVSize];
*salt = [self randomDataOfLength:kPBKDFSaltSize];
NSData *key = [self AESKeyForPassword:password salt:*salt];
size_t outLength;
NSMutableData *
cipherData = [NSMutableData dataWithLength:data.length +
kAlgorithmBlockSize];
CCCryptorStatus
result = CCCrypt(kCCEncrypt, // operation
kAlgorithm, // Algorithm
kCCOptionPKCS7Padding, // options
key.bytes, // key
key.length, // keylength
(*iv).bytes,// iv
data.bytes, // dataIn
data.length, // dataInLength,
cipherData.mutableBytes, // dataOut
cipherData.length, // dataOutAvailable
&outLength); // dataOutMoved
if (result == kCCSuccess) {
cipherData.length = outLength;
}
else {
if (error) {
*error = [NSError errorWithDomain:kRNCryptManagerErrorDomain
code:result
userInfo:nil];
}
return nil;
}
return cipherData;
}
// ===================
+ (NSData *)randomDataOfLength:(size_t)length {
NSMutableData *data = [NSMutableData dataWithLength:length];
int result = SecRandomCopyBytes(kSecRandomDefault, length,data.mutableBytes);
NSLog(@"%d",result);
NSAssert1(result == 0, @"Unable to generate random bytes: %d", errno);
//NSAssert( @"Unable to generate random bytes: %d", errno);
return data;
}
// ===================
// Replace this with a 10,000 hash calls if you don't have CCKeyDerivationPBKDF
+ (NSData *)AESKeyForPassword:(NSString *)password
salt:(NSData *)salt {
NSMutableData *
derivedKey = [NSMutableData dataWithLength:kAlgorithmKeySize];
int result = CCKeyDerivationPBKDF(kCCPBKDF2, // algorithm
password.UTF8String, // password
password.length, // passwordLength
salt.bytes, // salt
salt.length, // saltLen
kCCPRFHmacAlgSHA1, // PRF
kPBKDFRounds, // rounds
derivedKey.mutableBytes, // derivedKey
derivedKey.length); // derivedKeyLen
NSLog(@"%d",result);
// Do not log password here
NSAssert1(result == kCCSuccess,@"Unable to create AES key for password: %d", result);
//NSAssert(@"Unable to create AES key for password: %d", result);
return derivedKey;
}
@end
The code placed above implementation is of CommonCrypto/CommonKeyDerivation.h which was not found be me xcode and hence I put code directly at the top.
