AES暗号化について(下)
8121 ワード
前回はJavaにおけるAES暗号化が提供されていましたが、使用時には一般的にJavaがサーバまたは端末として、iosが端末として関与する可能性があるため、少なくとも私が遭遇したシーンはそうだったので、IOS端のAES暗号化を貼り付けました.まず私の次のコードはNSDataベースのCategoryです.コードを付けましょう:
NSData+AES256.h
NSData+AES256.m
NSData+AES256.h
#import
#import
#import
@interface NSData (AES256)
+ (NSData *)AES256EncryptWithPlainText:(NSString *)plain; /* , */
+ (NSData *)AES256DecryptWithCiphertext:(NSString *)ciphertexts; /* ， */
@end
NSData+AES256.m
#import "NSData+AES256.h"
#define PASSWORD @"Per vallum duces Labant"
static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const NSUInteger kAlgorithmKeySize = kCCKeySizeAES256;
const NSUInteger kPBKDFRounds = 10000; // ~80ms on an iPhone 4
//static Byte saltBuff[] = {0,1,2,3,4,5,6,7,8,9,0xA,0xB,0xC,0xD,0xE,0xF};
static NSString *key = @"H@}+T@b}hS/5798DGILXURXp'o$cC%!XpOibP N6Gg@1um*kAS; [7y&BcSSo+m*";
static Byte ivBuff[] = {0xA,1,0xB,5,4,0xF,7,9,0x17,3,1,6,8,0xC,0xD,91};
@implementation NSData (AES256)
+ (NSData *)AESKeyForPassword:(NSString *)password{ //Derive a key from a text password/passphrase
NSMutableData *derivedKey = [NSMutableData dataWithLength:kAlgorithmKeySize];
//NSData *salt = [NSData dataWithBytes:saltBuff length:kCCKeySizeAES128];
NSData *salt = [key dataUsingEncoding:NSUTF8StringEncoding];
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 derive:
NSAssert(result == kCCSuccess,
@"Unable to create AES key for spassword: %d", result);
return derivedKey;
}
/* */
+ (NSData*)AES256EncryptWithPlainText:(NSString *)plain {
NSData *plainText = [plain dataUsingEncoding:NSUTF8StringEncoding];
// 'key' should be 32 bytes for AES256, will be null-padded otherwise
char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
NSUInteger dataLength = [plainText length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
bzero(buffer, sizeof(buffer));
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,kCCOptionPKCS7Padding,
[[NSData AESKeyForPassword:PASSWORD] bytes], kCCKeySizeAES256,
ivBuff /* initialization vector (optional) */,
[plainText bytes], dataLength, /* input */
buffer, bufferSize, /* output */
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
NSData *encryptData = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
NSLog(@"%@", [encryptData base64Encoding]);
return encryptData;
}
free(buffer); //free the buffer;
return nil;
}
/* */
+ (NSData *)AES256DecryptWithCiphertext:(NSString *)ciphertexts{
NSData *cipherData = [NSData dataWithBase64EncodedString:ciphertexts];
// 'key' should be 32 bytes for AES256, will be null-padded otherwise
char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
NSUInteger dataLength = [cipherData length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
[[NSData AESKeyForPassword:PASSWORD] bytes], kCCKeySizeAES256,
ivBuff ,/* initialization vector (optional) */
[cipherData bytes], dataLength, /* input */
buffer, bufferSize, /* output */
&numBytesDecrypted);
if (cryptStatus == kCCSuccess) {
NSData *encryptData = [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
return encryptData;
}
free(buffer); //free the buffer;
return nil;
}
+ (id)dataWithBase64EncodedString:(NSString *)string;
{
if (string == nil)
[NSException raise:NSInvalidArgumentException format:nil];
if ([string length] == 0)
return [NSData data];
static char *decodingTable = NULL;
if (decodingTable == NULL)
{
decodingTable = malloc(256);
if (decodingTable == NULL)
return nil;
memset(decodingTable, CHAR_MAX, 256);
NSUInteger i;
for (i = 0; i < 64; i++)
decodingTable[(short)encodingTable[i]] = i;
}
const char *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];
if (characters == NULL) // Not an ASCII string!
return nil;
char *bytes = malloc((([string length] + 3) / 4) * 3);
if (bytes == NULL)
return nil;
NSUInteger length = 0;
NSUInteger i = 0;
while (YES)
{
char buffer[4];
short bufferLength;
for (bufferLength = 0; bufferLength < 4; i++)
{
if (characters[i] == '\0')
break;
if (isspace(characters[i]) || characters[i] == '=')
continue;
buffer[bufferLength] = decodingTable[(short)characters[i]];
if (buffer[bufferLength++] == CHAR_MAX) // Illegal character!
{
free(bytes);
return nil;
}
}
if (bufferLength == 0)
break;
if (bufferLength == 1) // At least two characters are needed to produce one byte!
{
free(bytes);
return nil;
}
// Decode the characters in the buffer to bytes.
bytes[length++] = (buffer[0] << 2) | (buffer[1] >> 4);
if (bufferLength > 2)
bytes[length++] = (buffer[1] << 4) | (buffer[2] >> 2);
if (bufferLength > 3)
bytes[length++] = (buffer[2] << 6) | buffer[3];
}
bytes = realloc(bytes, length);
return [NSData dataWithBytesNoCopy:bytes length:length];
}
- (NSString *)base64Encoding;
{
if ([self length] == 0)
return @"";
char *characters = malloc((([self length] + 2) / 3) * 4);
if (characters == NULL)
return nil;
NSUInteger length = 0;
NSUInteger i = 0;
while (i < [self length])
{
char buffer[3] = {0,0,0};
short bufferLength = 0;
while (bufferLength < 3 && i < [self length])
buffer[bufferLength++] = ((char *)[self bytes])[i++];
// Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.
characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2];
characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];
if (bufferLength > 1)
characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];
else characters[length++] = '=';
if (bufferLength > 2)
characters[length++] = encodingTable[buffer[2] & 0x3F];
else characters[length++] = '=';
}
return [[[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES] autorelease];
}
@end