对称加密算法：指加密和解密使用相同密钥的加密算法（包括DES算法，3DES算法，RC5算法，AES算法等）。本文讲述AES算法和DES算法，AES和DES都包含两种加密算法的加密方式分别为ECB和CBC。
AES：高级加密标准，是美国联邦政府采用的一种区块加密标准。
DES：数据加密标准，(现在用的比较少，因为它的加密强度不够，能够暴力破解)。
ECB：电子密码本，就是每个块都是独立加密的。
CBC：密码块链，使用一个密钥和一个初始化向量(IV)对数据执行加密转换。
EncryptionTools.h 文件代码如下：
#import
#import
@interface EncryptionTools : NSObject
/**
* AES加密
*
* @param string 要加密的字符串
* @param keyString 加密密钥
* @param iv 初始化向量(8个字节)
*
* @return 返回加密后的base64编码字符串
*/
+ (NSString *)aesEncryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv;
/**
* AES解密
*
* @param string 加密并base64编码后的字符串
* @param keyString 解密密钥
* @param iv 初始化向量(8个字节)
*
* @return 返回解密后的字符串
*/
+ (NSString *)aesDecryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv;
/**
* DES加密
*
* @param string 要加密的字符串
* @param keyString 加密密钥
* @param iv 初始化向量(8个字节)
*
* @return 返回加密后的base64编码字符串
*/
+ (NSString *)desEncryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv;
/**
* DES解密
*
* @param string 加密并base64编码后的字符串
* @param keyString 解密密钥
* @param iv 初始化向量(8个字节)
*
* @return 返回解密后的字符串
*/
+ (NSString *)desDecryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv;
@end
EncryptionTools.m 文件代码如下：
#import "EncryptionTools.h"
@implementation EncryptionTools
//AES加密
+ (NSString *)aesEncryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv {
// 设置秘钥
NSData *keyData = [keyString dataUsingEncoding:NSUTF8StringEncoding];
uint8_t cKey[kCCKeySizeAES128];
bzero(cKey, sizeof(cKey));
[keyData getBytes:cKey length:kCCKeySizeAES128];
// 设置iv
uint8_t cIv[kCCBlockSizeAES128];
bzero(cIv, kCCBlockSizeAES128);
int option = 0;
if (iv) {
[iv getBytes:cIv length:kCCBlockSizeAES128];
option = kCCOptionPKCS7Padding;
} else {
option = kCCOptionPKCS7Padding | kCCOptionECBMode;
}
// 设置输出缓冲区
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
size_t bufferSize = [data length] + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
// 开始加密
size_t encryptedSize = 0;
/**
@constant kCCAlgorithmAES 高级加密标准，128位(默认)
@constant kCCAlgorithmDES 数据加密标准
*/
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmAES,
option,
cKey,
kCCKeySizeAES128,
cIv,
[data bytes],
[data length],
buffer,
bufferSize,
&encryptedSize);
NSData *result = nil;
if (cryptStatus == kCCSuccess) {
result = [NSData dataWithBytesNoCopy:buffer length:encryptedSize];
} else {
free(buffer);
NSLog(@"[错误] 加密失败|状态编码: %d", cryptStatus);
}
return [result base64EncodedStringWithOptions:0];
}
//AES解密
+ (NSString *)aesDecryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv {
// 设置秘钥
NSData *keyData = [keyString dataUsingEncoding:NSUTF8StringEncoding];
uint8_t cKey[kCCKeySizeAES128];
bzero(cKey, sizeof(cKey));
[keyData getBytes:cKey length:kCCKeySizeAES128];
// 设置iv
uint8_t cIv[kCCBlockSizeAES128];
bzero(cIv, kCCBlockSizeAES128);
int option = 0;
if (iv) {
[iv getBytes:cIv length:kCCBlockSizeAES128];
option = kCCOptionPKCS7Padding;
} else {
option = kCCOptionPKCS7Padding | kCCOptionECBMode;
}
// 设置输出缓冲区，options参数很多地方是直接写0，但是在实际过程中可能出现回车的字符串导致解不出来
NSData *data = [[NSData alloc] initWithBase64EncodedString:string options:NSDataBase64DecodingIgnoreUnknownCharacters];
size_t bufferSize = [data length] + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
// 开始解密
size_t decryptedSize = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
kCCAlgorithmAES128,
option,
cKey,
kCCKeySizeAES128,
cIv,
[data bytes],
[data length],
buffer,
bufferSize,
&decryptedSize);
NSData *result = nil;
if (cryptStatus == kCCSuccess) {
result = [NSData dataWithBytesNoCopy:buffer length:decryptedSize];
} else {
free(buffer);
NSLog(@"[错误] 解密失败|状态编码: %d", cryptStatus);
}
return [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];
}
//DES加密
+ (NSString *)desEncryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv {
// 设置秘钥
NSData *keyData = [keyString dataUsingEncoding:NSUTF8StringEncoding];
uint8_t cKey[kCCKeySizeDES];
bzero(cKey, sizeof(cKey));
[keyData getBytes:cKey length:kCCKeySizeDES];
// 设置iv
uint8_t cIv[kCCBlockSizeDES];
bzero(cIv, kCCBlockSizeDES);
int option = 0;
if (iv) {
[iv getBytes:cIv length:kCCBlockSizeDES];
option = kCCOptionPKCS7Padding;
} else {
option = kCCOptionPKCS7Padding | kCCOptionECBMode;
}
// 设置输出缓冲区
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
size_t bufferSize = [data length] + kCCBlockSizeDES;
void *buffer = malloc(bufferSize);
// 开始加密
size_t encryptedSize = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmDES,
option,
cKey,
kCCKeySizeDES,
cIv,
[data bytes],
[data length],
buffer,
bufferSize,
&encryptedSize);
NSData *result = nil;
if (cryptStatus == kCCSuccess) {
result = [NSData dataWithBytesNoCopy:buffer length:encryptedSize];
} else {
free(buffer);
NSLog(@"[错误] 加密失败|状态编码: %d", cryptStatus);
}
return [result base64EncodedStringWithOptions:0];
}
//DES解密
+ (NSString *)desDecryptString:(NSString *)string keyString:(NSString *)keyString iv:(NSData *)iv {
// 设置秘钥
NSData *keyData = [keyString dataUsingEncoding:NSUTF8StringEncoding];
uint8_t cKey[kCCKeySizeDES];
bzero(cKey, sizeof(cKey));
[keyData getBytes:cKey length:kCCKeySizeDES];
// 设置iv
uint8_t cIv[kCCBlockSizeDES];
bzero(cIv, kCCBlockSizeDES);
int option = 0;
if (iv) {
[iv getBytes:cIv length:kCCBlockSizeDES];
option = kCCOptionPKCS7Padding;
} else {
option = kCCOptionPKCS7Padding | kCCOptionECBMode;
}
// 设置输出缓冲区，options参数很多地方是直接写0，但是在实际过程中可能出现回车的字符串导致解不出来
NSData *data = [[NSData alloc] initWithBase64EncodedString:string options:NSDataBase64DecodingIgnoreUnknownCharacters];
size_t bufferSize = [data length] + kCCBlockSizeDES;
void *buffer = malloc(bufferSize);
// 开始解密
size_t decryptedSize = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
kCCAlgorithmDES,
option,
cKey,
kCCKeySizeDES,
cIv,
[data bytes],
[data length],
buffer,
bufferSize,
&decryptedSize);
NSData *result = nil;
if (cryptStatus == kCCSuccess) {
result = [NSData dataWithBytesNoCopy:buffer length:decryptedSize];
} else {
free(buffer);
NSLog(@"[错误] 解密失败|状态编码: %d", cryptStatus);
}
return [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];
}
@end
ViewController.m 文件调用
#import "ViewController.h"
#import "EncryptionTools.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
//iv向量
NSString *iv = @"abcdefghijklmnop";
//转化为data，在java中是一个byte类型
NSData *ivData = [iv dataUsingEncoding:NSUTF8StringEncoding];
/****************************AES********************************/
//aes-ecb加密, iv直接传nil就行
NSString *aesEcbE = [EncryptionTools aesEncryptString:@"这个是AES-ECB加密" keyString:@"abcdefghi1234567" iv:nil];
NSLog(@"aes-ecb加密: %@", aesEcbE);
//aes-ecb解密, iv直接传nil就行
NSString *aesEcbD = [EncryptionTools aesDecryptString:@"BKsrfQeUQnMEbPUxcbcy79Xuq4t2i04MgoFRDB8p7CI=" keyString:@"abcdefghi1234567" iv:nil];
NSLog(@"aes-ecb解密: %@", aesEcbD);
//aes-cbc加密
NSString *aesCbcE = [EncryptionTools aesEncryptString:@"这个是AES-CBC加密" keyString:@"abcdefghi1234567" iv:ivData];
NSLog(@"aes-cbc加密: %@", aesCbcE);
//aes-cbc解密
NSString *aesCbcD = [EncryptionTools aesDecryptString:@"eo9dQHISb7Uh6H7iYjPa5PyxaBfU1oFKdJiwJsqXIsg=" keyString:@"abcdefghi1234567" iv:ivData];
NSLog(@"aes-cbc解密: %@", aesCbcD);
/****************************DES********************************/
//aes-ecb加密, iv直接传nil就行
NSString *desEcbE = [EncryptionTools desEncryptString:@"这个是DES-ECB加密" keyString:@"abcdefghi1234567" iv:nil];
NSLog(@"des-ecb加密: %@", desEcbE);
//aes-ecb解密, iv直接传nil就行
NSString *desEcbD = [EncryptionTools desDecryptString:@"fu2IYaT9ovofPt1trAt5nsgyPf16zJYB" keyString:@"abcdefghi1234567" iv:nil];
NSLog(@"des-ecb解密: %@", desEcbD);
//aes-cbc加密
NSString *desCbcE = [EncryptionTools desEncryptString:@"这个是DES-ECB加密" keyString:@"abcdefghi1234567" iv:ivData];
NSLog(@"des-cbc加密: %@", desCbcE);
//aes-cbc解密
NSString *desCbcD = [EncryptionTools desDecryptString:@"qqeY0KWFB6WikoZgtmiy9nrB8SLjsv90" keyString:@"abcdefghi1234567" iv:ivData];
NSLog(@"des-cbc解密: %@", desCbcD);
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
打印结果如下：
Paste_Image.png