iOS开发之Objective-c的AES128加密和解密算法的实现

 

#import <Foundation/Foundation.h>

#import <CommonCrypto/CommonDigest.h>

#import <CommonCrypto/CommonCryptor.h>

#import "NSData+AES.h"

@interface NSString (AES)

//加密字符串

- (NSString*)aes128Encrypt:(NSString *)aKey;

//解密字符串

- (NSString*)aes128Decrypt:(NSString *)aKey;

@end

 

#define gIv             @"0102030405060708" //自行修改16位 -->偏移量

@implementation NSString (AES256)

 - (NSString *)aes128Encrypt:(NSString *)aKey

{

    char keyPtr[kCCKeySizeAES128+1];

    memset(keyPtr, 0, sizeof(keyPtr));

    [aKey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    

    char ivPtr[kCCBlockSizeAES128+1];

    memset(ivPtr, 0, sizeof(ivPtr));

    [gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

    

    NSData* data = [self dataUsingEncoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [data length];

    

    int diff = kCCKeySizeAES128 - (dataLength % kCCKeySizeAES128);

    int newSize = 0;

    

    if(diff > 0)

    {

        newSize = dataLength + diff;

    }

    

    char dataPtr[newSize];

    memcpy(dataPtr, [data bytes], [data length]);

    for(int i = 0; i < diff; i++)

    {

        dataPtr[i + dataLength] = 0x00;

    }

    

    size_t bufferSize = newSize + kCCBlockSizeAES128;

    void *buffer = malloc(bufferSize);

    memset(buffer, 0, bufferSize);

    

    size_t numBytesCrypted = 0;

    

    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,

                                          kCCAlgorithmAES128,

                                          kCCOptionPKCS7Padding,  // 补码方式

                                          keyPtr,

                                          kCCKeySizeAES128,

                                          ivPtr,

                                          dataPtr,

                                          sizeof(dataPtr),

                                          buffer,

                                          bufferSize,

                                          &numBytesCrypted);

    

    if (cryptStatus == kCCSuccess) {

        NSData *result = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];

        if (result && result.length > 0) {

            

            Byte *datas = (Byte*)[result bytes];

            NSMutableString *output = [NSMutableString stringWithCapacity:result.length * 2];

            for(int i = 0; i < result.length; i++){

                [output appendFormat:@"%02x", datas[i]];

            }

            return output;

        }

    }

    free(buffer);

    return nil;

}

 

- (NSString *)aes128Decrypt:(NSString *)aKey

{

    char keyPtr[kCCKeySizeAES128 + 1];

    memset(keyPtr, 0, sizeof(keyPtr));

    [aKey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    

    char ivPtr[kCCBlockSizeAES128 + 1];

    memset(ivPtr, 0, sizeof(ivPtr));

    [gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

    

    NSMutableData *data = [NSMutableData dataWithCapacity:self.length / 2];

    unsigned char whole_byte;

    char byte_chars[3] = {'\0','\0','\0'};

    int i;

    for (i=0; i < [self length] / 2; i++) {

        byte_chars[0] = [self characterAtIndex:i*2];

        byte_chars[1] = [self characterAtIndex:i*2+1];

        whole_byte = strtol(byte_chars, NULL, 16);

        [data appendBytes:&whole_byte length:1];

    }

    

    NSUInteger dataLength = [data length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;

    void *buffer = malloc(bufferSize);

    

    size_t numBytesCrypted = 0;

    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,

                                          kCCAlgorithmAES128,

                                          kCCOptionPKCS7Padding,

                                          keyPtr,

                                          kCCBlockSizeAES128,

                                          ivPtr,

                                          [data bytes],

                                          dataLength,

                                          buffer,

                                          bufferSize,

                                          &numBytesCrypted);

    if (cryptStatus == kCCSuccess) {

        NSData *resultData = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];

        return [[NSString alloc] initWithData:resultData encoding:NSUTF8StringEncoding];

    }

    free(buffer);

    return nil;

}

@end

 

iOS Objective c 16进制字符串转为二进制数组

原文：http://lizhuang.iteye.com/blog/2060143

@implementation NSString (StringToHexData)

//
// Decodes an NSString containing hex encoded bytes into an NSData object
//
- (NSData *) stringToHexData
{
    int len = [self length] / 2;    // Target length
    unsigned char *buf = malloc(len)
    unsigned char *whole_byte = buf;
    char byte_chars[3] = {'\0','\0','\0'};

    int i;
    for (i=0; i < [self length] / 2; i++) {
        byte_chars[0] = [self characterAtIndex:i*2];
        byte_chars[1] = [self characterAtIndex:i*2+1];
        *whole_byte = strtol(byte_chars, NULL, 16);
        whole_byte++;
    }

    NSData *data = [NSData dataWithBytes:buf length:len];
    free( buf );
    return data;
}
@end
@implementation NSData (DataToHexString)

- (NSString *) dataToHexString
{
    NSUInteger          len = [self length];
    char *              chars = (char *)[self bytes];
    NSMutableString *   hexString = [[NSMutableString alloc] init];

    for(NSUInteger i = 0; i < len; i++ )
        [hexString appendString:[NSString stringWithFormat:@"%0.2hhx", chars[i]]];

    return hexString;
}
@end