AES128_CBC模式加密

　　高级加密标准（英语：Advanced Encryption Standard，缩写：AES），在密码学中又称Rijndael加密法，是美国联邦政府采用的一种区块加密标准。这个标准用来替代原先的DES，已经被多方分析且广为全世界所使用。经过五年的甄选流程，高级加密标准由美国国家标准与技术研究院（NIST）于2001年11月26日发布于FIPS PUB 197，并在2002年5月26日成为有效的标准。2006年，高级加密标准已然成为对称密钥加密中最流行的算法之一。

1.字符串加密(http://www.seacha.com/tools/aes.html)

　　原始字符串：SuperDo.Team
　　加密后字符串：f3de96947b786e45fe338f06e2baeb2a

2.字符串解密（iOS）

　　[1].对NSData进行拓展

　　NSData+AES128.h

@interface NSData (AES128)
- (NSData *)AES128_encrypt:(NSString *)key padding:(NSString *)pad;;
- (NSData *)AES128_decrypt:(NSString *)key padding:(NSString *)pad;;
@end

　　NSData+AES128.m

#import "NSData+AES128.h"

@implementation NSData (AES128)
- (NSData *)AES128_encrypt:(NSString *)key padding:(NSString *)pad;   //加密
{
    char keyPtr[kCCKeySizeAES128+1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [self length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding ,
                                          keyPtr, kCCBlockSizeAES128,
                                          [pad UTF8String],
                                          [self bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }
    free(buffer);
    return nil;
}

- (NSData *)AES128_decrypt:(NSString *)key padding:(NSString *)pad;  //解密
{
    char keyPtr[kCCKeySizeAES128+1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [self length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding ,
                                          keyPtr, kCCBlockSizeAES128,
                                          [pad UTF8String],
                                          [self bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesDecrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
        
    }
    free(buffer);
    return nil;
}

@end

　　[2].对NSString进行拓展

　　NSString+AES128.h

#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonCryptor.h>

@interface NSString (AES128)

-(NSString *) AES128_decrypt:(NSString *)key padding:(NSString *)pad;
-(NSString *) AES128_encrypt:(NSString *)key padding:(NSString *)pad;;
@end

　　NSString+AES128.m

#import "NSString+AES128.h"
#import "NSData+AES128.h"

@implementation NSString (AES128)
-(NSString *) AES128_encrypt:(NSString *)key padding:(NSString *)pad;
{
    const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
    NSData *data = [NSData dataWithBytes:cstr length:self.length];
    //对数据进行加密
    NSData *result = [data AES128_encrypt:key padding:pad];
    
    //转换为2进制字符串
    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;
    }
    return nil;
}

-(NSString *) AES128_decrypt:(NSString *)key padding:(NSString *)pad;
{
    //转换为2进制Data
    NSMutableData *data = [NSMutableData dataWithCapacity:self.length / 2];
    unsigned char whole_byte;
    char byte_chars[3] = {'','',''};
    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];
    }
    
    //对数据进行解密
    NSData* result = [data AES128_decrypt:key padding:pad];
    if (result && result.length > 0) {
        return [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];
    }
    return nil;
}
@end

3.验证

　　main.m

#import <Foundation/Foundation.h>
#import "NSString+AES128.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        NSLog(@"Hello, World!");
        NSString *str = [@"f3de96947b786e45fe338f06e2baeb2a" AES128_decrypt:@"123456" padding:@"8888888877777777"];
        NSLog(@"%@",str);
    }
    return 0;
}

　　验证结果：
　　2016-01-18 19:27:48.703 AES_128_CBC[30636:2351517] Hello, World!
　　2016-01-18 19:27:48.704 AES_128_CBC[30636:2351517] SuperDo.Team
　　Program ended with exit code: 0

　　完美的搞定AES128_CBC模式加密了！

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转载自【宝宝巴士SuperDo团队】 原文链接: http://www.cnblogs.com/superdo/p/5140243.html