[iOS]objective-c AES/DES/3DES等加密算法实现

objective-c对AES/DES/3DES等加密提供了统一的加密方法CCCrypt进行实现，目前主要支持的算法有 @constant kCCAlgorithmAES128 Advanced Encryption Standard @constant kCCAlgorithmAES Advanced Encryption Standard, 128-bit block @constant kCCAlgorithmDES Data Encryption Standard @constant kCCAlgorithm3DES Triple-DES, three key, EDE configuration @constant kCCAlgorithmCAST CAST @constant kCCAlgorithmRC4 RC4 stream cipher @constant kCCAlgorithmBlowfish Blowfish block cipher ---

/*!
@enum       CCAlgorithm
@abstract   Encryption algorithms implemented by this module.

@constant   kCCAlgorithmAES128  Advanced Encryption Standard, 128-bit block
This is kept for historical reasons.  It's
preferred now to use kCCAlgorithmAES since
128-bit blocks are part of the standard.
@constant   kCCAlgorithmAES     Advanced Encryption Standard, 128-bit block
@constant   kCCAlgorithmDES     Data Encryption Standard
@constant   kCCAlgorithm3DES    Triple-DES, three key, EDE configuration
@constant   kCCAlgorithmCAST    CAST
@constant   kCCAlgorithmRC4     RC4 stream cipher
@constant   kCCAlgorithmBlowfish    Blowfish block cipher
*/
enum {
kCCAlgorithmAES128 = 0,
kCCAlgorithmAES = 0,
kCCAlgorithmDES,
kCCAlgorithm3DES,
kCCAlgorithmCAST,
kCCAlgorithmRC4,
kCCAlgorithmRC2,
kCCAlgorithmBlowfish
};

以下是DES的代码实现，可供使用的加密算法有des，3des，aes等,根据需要替换相应的参数即可。

- (NSString*) des:(NSString*) key
{
const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
NSData *data = [NSData dataWithBytes:cstr length:self.length];

CCCryptorStatus ccStatus;
uint8_t *dataOut = NULL;
size_t dataOutAvailable = 0; //size_t  是操作符sizeof返回的结果类型
size_t dataOutMoved = 0;

dataOutAvailable = (data.length + kCCBlockSizeDES) & ~(kCCBlockSizeDES - 1);
dataOut = malloc( dataOutAvailable * sizeof(uint8_t));
memset((void *)dataOut, 0x0, dataOutAvailable);//将已开辟内存空间buffer的首 1 个字节的值设为值 0

NSString *initIv = key;
const void *vkey = (const void *) [key UTF8String];
const void *iv = (const void *) [initIv UTF8String];

//CCCrypt函数 加密/解密
ccStatus = CCCrypt(kCCEncrypt,               //  加密/解密
kCCAlgorithmDES,          //  加密根据哪个标准（des，3des，aes。。。。）
kCCOptionPKCS7Padding,    //  选项分组密码算法(des:对每块分组加一次密  3DES：对每块分组加三个不同的密)
vkey,                     //  密钥
kCCKeySizeDES,            //  DES 密钥的大小（kCCKeySizeDES=8）
iv,                       //  可选的初始矢量
[data bytes],             //  数据的存储单元
data.length,              // 数据的大小
(void *)dataOut,          // 用于返回数据
dataOutAvailable,
&dataOutMoved;);

NSString *result = [[[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)dataOut length:(NSUInteger)dataOutMoved] encoding:NSUTF8StringEncoding] autorelease];

return result;

}

配合Base64方式使用

- (NSString*) des_base64:(NSString*) key
{
const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
NSData *data = [NSData dataWithBytes:cstr length:self.length];

CCCryptorStatus ccStatus;
uint8_t *dataOut = NULL;
size_t dataOutAvailable = 0; //size_t  是操作符sizeof返回的结果类型
size_t dataOutMoved = 0;

dataOutAvailable = (data.length + kCCBlockSizeDES) & ~(kCCBlockSizeDES - 1);
dataOut = malloc( dataOutAvailable * sizeof(uint8_t));
memset((void *)dataOut, 0x0, dataOutAvailable);//将已开辟内存空间buffer的首 1 个字节的值设为值 0

NSString *initIv = key;
const void *vkey = (const void *) [key UTF8String];
const void *iv = (const void *) [initIv UTF8String];

//CCCrypt函数 加密/解密
ccStatus = CCCrypt(kCCEncrypt,               //  加密/解密
kCCAlgorithmDES,          //  加密根据哪个标准（des，3des，aes。。。。）
kCCOptionPKCS7Padding,    //  选项分组密码算法(des:对每块分组加一次密  3DES：对每块分组加三个不同的密)
vkey,                     //  密钥
kCCKeySizeDES,            //  DES 密钥的大小（kCCKeySizeDES=8）
iv,                       //  可选的初始矢量
[data bytes],             //  数据的存储单元
data.length,              // 数据的大小
(void *)dataOut,          // 用于返回数据
dataOutAvailable,
&dataOutMoved;);


NSData *dataFor = [NSData dataWithBytes:(const void *)dataOut length:(NSUInteger)dataOutMoved];
NSString *result = [GTMBase64 stringByEncodingData:dataFor];

return result;

}