.h中的方法名

#import <Foundation/Foundation.h>

@interface NSData (Security)
- (NSData *)AES256EncryptWithKey:(NSString *)key;
- (NSData *)AES256DecryptWithKey:(NSString *)key;


- (NSString*)Base64Encode;
- (NSString*)Base64Decode;
@end


@interface NSString (Security)
-(NSString*)AES256Encrypt:(NSString*)key;
-(NSString*)AES256Dncrypt:(NSString*)key;


- (NSString *)MD5EncryptLower;
- (NSString *)MD5EncryptUpper;


- (NSString*)Base64Encode;
- (NSString*)Base64Decode;
@end

.m文件中

#import "XYZSecurity.h"
#import <CommonCrypto/CommonCryptor.h>
#import <CommonCrypto/CommonDigest.h>
#import "GTMBase64.h"
@implementation NSData (Security)
- (NSData *)AES256EncryptWithKey:(NSString *)key //加密
{
NSData *keyData1;
NSData* bytes = [key dataUsingEncoding:NSUTF8StringEncoding];
NSInteger length = 32;

if (bytes.length>32) {
length = bytes.length;
}
char keyPtr0[length+1];
bzero(keyPtr0,sizeof(keyPtr0));
[key getCString:keyPtr0 maxLength:sizeof(keyPtr0) encoding:NSUTF8StringEncoding];
keyData1 = [[NSData alloc] initWithBytes:keyPtr0 length:32];
//AES256加密，密鑰應該是32位的
//對於塊加密算法，輸出大小總是等於或小於輸入大小加上一個塊的大小
//所以在下邊需要再加上一個塊的大小
NSUInteger dataLength = [self length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);

size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,
kCCOptionPKCS7Padding/*這裏就是剛才說到的PKCS7Padding填充了*/ | kCCOptionECBMode,
[keyData1 bytes], kCCKeySizeAES256,
NULL,/* 初始化向量(可選) */
[self bytes], dataLength,/*輸入*/
buffer, bufferSize,/* 輸出 */
&numBytesEncrypted);

if (cryptStatus == kCCSuccess) {
return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}
free(buffer);//釋放buffer
return nil;

}


-(NSData *)AES256DecryptWithKey:(NSString *)key
{
// ‘key‘ should be 32 bytes for AES256, will be null-padded otherwise

NSData* bytes = [key dataUsingEncoding:NSUTF8StringEncoding];
NSInteger length = 32;

if (bytes.length>32) {
length = bytes.length;
}

char keyPtr[length+1]; // room for terminator (unused)
bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)

// fetch key data
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

NSUInteger dataLength = [self 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 numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
keyPtr, kCCKeySizeAES256,
NULL /* initialization vector (optional) */,
[self 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;

}

- (NSString*)Base64Encode{
NSData* data = [GTMBase64 encodeData:self];
NSString *base64String = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
return base64String;
}
- (NSString*)Base64Decode{
NSData* data = [GTMBase64 decodeData:self];
NSString *base64String = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
return base64String;
}
@end
@implementation NSString (Security)
-(NSString*)AES256Encrypt:(NSString*)key{
NSData * plain=[self dataUsingEncoding:NSUTF8StringEncoding];
NSData * cipher=[plain AES256EncryptWithKey:key];
NSString * string=[cipher base64EncodedStringWithOptions:0];
return string;
}
-(NSString*)AES256Dncrypt:(NSString*)key{
NSData * plain=[self dataUsingEncoding:NSUTF8StringEncoding];
NSData * cipher=[plain AES256DecryptWithKey:key];
NSString * string=[cipher base64EncodedStringWithOptions:0];
return string;
}









- (NSString *)MD5EncryptLower {
const char *str = self.UTF8String;
uint8_t buffer[CC_MD5_DIGEST_LENGTH];

CC_MD5(str, (CC_LONG)strlen(str), buffer);

return [self stringFromBytes:buffer length:CC_MD5_DIGEST_LENGTH];
}
- (NSString *)stringFromBytes:(uint8_t *)bytes length:(int)length {
NSMutableString *strM = [NSMutableString string];

for (int i = 0; i < length; i++) {
[strM appendFormat:@"%02x", bytes[i]];
}

return [strM copy];
}
/** 大寫MD5*/
- (NSString *)MD5EncryptUpper {

const char *cStr = [self UTF8String];
unsigned char result[16];
CC_MD5( cStr, strlen(cStr), result );
return [NSString stringWithFormat:@"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
result[0], result[1], result[2], result[3],
result[4], result[5], result[6], result[7],
result[8], result[9], result[10], result[11],
result[12], result[13], result[14], result[15]
];
}




- (NSString*)Base64Encode{
NSData *data = [self dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
NSString *base64String = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
return base64String;
}
- (NSString*)Base64Decode{
NSData *data = [self dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
NSString *base64String = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
return base64String;
}
@end

一些加密方法