IOS成长之路-DES+Base64 加密、解密
DES是一种分组数据加密技术（先将数据分成固定长度的小数据块，之后进行加密），速度较快，适用于大量数据加密
3DES是一种基于DES的加密算法，使用3个不同密匙对同一个分组数据块进行3次加密，如此以使得密文强度更高。
相较于DES和3DES算法而言，AES算法有着更高的速度和资源使用效率，安全级别也较之更高了，被称为下一代加密标准。
用DES实现加密和解密的过程：（注释是我自己理解添加。不对的地方望指出）
.h文件中：
+ (NSString *)encryptWithText:(NSString *)sText;//加密 + (NSString *)decryptWithText:(NSString *)sText;//解密
.m文件中 （导包： #import "GTMBase64.h"（下面说） #import <CommonCrypto/CommonCryptor.h>）
+ (NSString *)encryptWithText:(NSString *)sText
{
//kCCEncrypt 加密
return [self encrypt:sText encryptOrDecrypt:kCCEncrypt key:@"des"];
}
+ (NSString *)decryptWithText:(NSString *)sText
{
//kCCDecrypt 解密
return [self encrypt:sText encryptOrDecrypt:kCCDecrypt key:@"des"];
}
+ (NSString *)encrypt:(NSString *)sText encryptOrDecrypt:(CCOperation)encryptOperation key:(NSString *)key
{
const void *dataIn;
size_t dataInLength;
if (encryptOperation == kCCDecrypt)//传递过来的是decrypt 解码
{
//解码 base64
NSData *decryptData = [GTMBase64 decodeData:[sText dataUsingEncoding:NSUTF8StringEncoding]];//转成utf-8并decode
dataInLength = [decryptData length];
dataIn = [decryptData bytes];
}
else //encrypt
{
NSData* encryptData = [sText dataUsingEncoding:NSUTF8StringEncoding];
dataInLength = [encryptData length];
dataIn = (const void *)[encryptData bytes];
}
/*
DES加密 ：用CCCrypt函数加密一下，然后用base64编码下，传过去
DES解密 ：把收到的数据根据base64，decode一下，然后再用CCCrypt函数解密，得到原本的数据
*/
CCCryptorStatus ccStatus;
uint8_t *dataOut = NULL; //可以理解位type/typedef 的缩写（有效的维护了代码，比如：一个人用int，一个人用long。最好用typedef来定义）
size_t dataOutAvailable = 0; //size_t 是操作符sizeof返回的结果类型
size_t dataOutMoved = 0;
dataOutAvailable = (dataInLength + 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 = @"12345678";
const void *vkey = (const void *) [key UTF8String];
const void *iv = (const void *) [initIv UTF8String];
//CCCrypt函数 加密/解密
ccStatus = CCCrypt(encryptOperation,// 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 加密和解密的密钥必须一致
kCCKeySizeDES,// DES 密钥的大小（kCCKeySizeDES=8）
iv, // 可选的初始矢量
dataIn, // 数据的存储单元
dataInLength,// 数据的大小
(void *)dataOut,// 用于返回数据
dataOutAvailable,
&dataOutMoved);
NSString *result = nil;
if (encryptOperation == kCCDecrypt)//encryptOperation==1 解码
{
//得到解密出来的data数据，改变为utf-8的字符串
result = [[[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)dataOut length:(NSUInteger)dataOutMoved] encoding:NSUTF8StringEncoding] autorelease];
}
else //encryptOperation==0 （加密过程中，把加好密的数据转成base64的）
{
//编码 base64
NSData *data = [NSData dataWithBytes:(const void *)dataOut length:(NSUInteger)dataOutMoved];
result = [GTMBase64 stringByEncodingData:data];
}
return result;
}
Base64.h
//
// GTMBase64.h
//
// Copyright 2006-2008 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy
// of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
//
#import <Foundation/Foundation.h>
#import "GTMDefines.h"
// GTMBase64
//
/// Helper for handling Base64 and WebSafeBase64 encodings
//
/// The webSafe methods use different character set and also the results aren't
/// always padded to a multiple of 4 characters. This is done so the resulting
/// data can be used in urls and url query arguments without needing any
/// encoding. You must use the webSafe* methods together, the data does not
/// interop with the RFC methods.
//
@interface GTMBase64 : NSObject
//
// Standard Base64 (RFC) handling
//
// encodeData:
//
/// Base64 encodes contents of the NSData object.
//
/// Returns:
/// A new autoreleased NSData with the encoded payload. nil for any error.
//
+(NSData *)encodeData:(NSData *)data;
// decodeData:
//
/// Base64 decodes contents of the NSData object.
//
/// Returns:
/// A new autoreleased NSData with the decoded payload. nil for any error.
//
+(NSData *)decodeData:(NSData *)data;
// encodeBytes:length:
//
/// Base64 encodes the data pointed at by |bytes|.
//
/// Returns:
/// A new autoreleased NSData with the encoded payload. nil for any error.
//
+(NSData *)encodeBytes:(const void *)bytes length:(NSUInteger)length;
// decodeBytes:length:
//
/// Base64 decodes the data pointed at by |bytes|.
//
/// Returns:
/// A new autoreleased NSData with the encoded payload. nil for any error.
//
+(NSData *)decodeBytes:(const void *)bytes length:(NSUInteger)length;
// stringByEncodingData:
//
/// Base64 encodes contents of the NSData object.
//
/// Returns:
/// A new autoreleased NSString with the encoded payload. nil for any error.
//
+(NSString *)stringByEncodingData:(NSData *)data;
// stringByEncodingBytes:length:
//
/// Base64 encodes the data pointed at by |bytes|.
//
/// Returns:
/// A new autoreleased NSString with the encoded payload. nil for any error.
//
+(NSString *)stringByEncodingBytes:(const void *)bytes length:(NSUInteger)length;
// decodeString:
//
/// Base64 decodes contents of the NSString.
//
/// Returns:
/// A new autoreleased NSData with the decoded payload. nil for any error.
//
+(NSData *)decodeString:(NSString *)string;
//
// Modified Base64 encoding so the results can go onto urls.
//
// The changes are in the characters generated and also allows the result to
// not be padded to a multiple of 4.
// Must use the matching call to encode/decode, won't interop with the
// RFC versions.
//
// webSafeEncodeData:padded:
//
/// WebSafe Base64 encodes contents of the NSData object. If |padded| is YES
/// then padding characters are added so the result length is a multiple of 4.
//
/// Returns:
/// A new autoreleased NSData with the encoded payload. nil for any error.
//
+(NSData *)webSafeEncodeData:(NSData *)data
padded:(BOOL)padded;
// webSafeDecodeData:
//
/// WebSafe Base64 decodes contents of the NSData object.
//
/// Returns:
/// A new autoreleased NSData with the decoded payload. nil for any error.
//
+(NSData *)webSafeDecodeData:(NSData *)data;
// webSafeEncodeBytes:length:padded:
//
/// WebSafe Base64 encodes the data pointed at by |bytes|. If |padded| is YES
/// then padding characters are added so the result length is a multiple of 4.
//
/// Returns:
/// A new autoreleased NSData with the encoded payload. nil for any error.
//
+(NSData *)webSafeEncodeBytes:(const void *)bytes
length:(NSUInteger)length
padded:(BOOL)padded;
// webSafeDecodeBytes:length:
//
/// WebSafe Base64 decodes the data pointed at by |bytes|.
//
/// Returns:
/// A new autoreleased NSData with the encoded payload. nil for any error.
//
+(NSData *)webSafeDecodeBytes:(const void *)bytes length:(NSUInteger)length;
// stringByWebSafeEncodingData:padded:
//
/// WebSafe Base64 encodes contents of the NSData object. If |padded| is YES
/// then padding characters are added so the result length is a multiple of 4.
//
/// Returns:
/// A new autoreleased NSString with the encoded payload. nil for any error.
//
+(NSString *)stringByWebSafeEncodingData:(NSData *)data
padded:(BOOL)padded;
// stringByWebSafeEncodingBytes:length:padded:
//
/// WebSafe Base64 encodes the data pointed at by |bytes|. If |padded| is YES
/// then padding characters are added so the result length is a multiple of 4.
//
/// Returns:
/// A new autoreleased NSString with the encoded payload. nil for any error.
//
+(NSString *)stringByWebSafeEncodingBytes:(const void *)bytes
length:(NSUInteger)length
padded:(BOOL)padded;
// webSafeDecodeString:
//
/// WebSafe Base64 decodes contents of the NSString.
//
/// Returns:
/// A new autoreleased NSData with the decoded payload. nil for any error.
//
+(NSData *)webSafeDecodeString:(NSString *)string;
@end
Base64.m
//
// GTMBase64.m
//
// Copyright 2006-2008 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy
// of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
//
#import "GTMBase64.h"
#import "GTMDefines.h"
static const char *kBase64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char *kWebSafeBase64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
static const char kBase64PaddingChar = '=';
static const char kBase64InvalidChar = 99;
static const char kBase64DecodeChars[] = {
// This array was generated by the following code:
// #include <sys/time.h>
// #include <stdlib.h>
// #include <string.h>
// main()
// {
// static const char Base64[] =
// "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
// char *pos;
// int idx, i, j;
// printf(" ");
// for (i = 0; i < 255; i += 8) {
// for (j = i; j < i + 8; j++) {
// pos = strchr(Base64, j);
// if ((pos == NULL) || (j == 0))
// idx = 99;
// else
// idx = pos - Base64;
// if (idx == 99)
// printf(" %2d, ", idx);
// else
// printf(" %2d/*%c*/,", idx, j);
// }
// printf("\n ");
// }
// }
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 62/*+*/, 99, 99, 99, 63/*/ */,
52/*0*/, 53/*1*/, 54/*2*/, 55/*3*/, 56/*4*/, 57/*5*/, 58/*6*/, 59/*7*/,
60/*8*/, 61/*9*/, 99, 99, 99, 99, 99, 99,
99, 0/*A*/, 1/*B*/, 2/*C*/, 3/*D*/, 4/*E*/, 5/*F*/, 6/*G*/,
7/*H*/, 8/*I*/, 9/*J*/, 10/*K*/, 11/*L*/, 12/*M*/, 13/*N*/, 14/*O*/,
15/*P*/, 16/*Q*/, 17/*R*/, 18/*S*/, 19/*T*/, 20/*U*/, 21/*V*/, 22/*W*/,
23/*X*/, 24/*Y*/, 25/*Z*/, 99, 99, 99, 99, 99,
99, 26/*a*/, 27/*b*/, 28/*c*/, 29/*d*/, 30/*e*/, 31/*f*/, 32/*g*/,
33/*h*/, 34/*i*/, 35/*j*/, 36/*k*/, 37/*l*/, 38/*m*/, 39/*n*/, 40/*o*/,
41/*p*/, 42/*q*/, 43/*r*/, 44/*s*/, 45/*t*/, 46/*u*/, 47/*v*/, 48/*w*/,
49/*x*/, 50/*y*/, 51/*z*/, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
};
static const char kWebSafeBase64DecodeChars[] = {
// This array was generated by the following code:
// #include <sys/time.h>
// #include <stdlib.h>
// #include <string.h>
// main()
// {
// static const char Base64[] =
// "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
// char *pos;
// int idx, i, j;
// printf(" ");
// for (i = 0; i < 255; i += 8) {
// for (j = i; j < i + 8; j++) {
// pos = strchr(Base64, j);
// if ((pos == NULL) || (j == 0))
// idx = 99;
// else
// idx = pos - Base64;
// if (idx == 99)
// printf(" %2d, ", idx);
// else
// printf(" %2d/*%c*/,", idx, j);
// }
// printf("\n ");
// }
// }
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 62/*-*/, 99, 99,
52/*0*/, 53/*1*/, 54/*2*/, 55/*3*/, 56/*4*/, 57/*5*/, 58/*6*/, 59/*7*/,
60/*8*/, 61/*9*/, 99, 99, 99, 99, 99, 99,
99, 0/*A*/, 1/*B*/, 2/*C*/, 3/*D*/, 4/*E*/, 5/*F*/, 6/*G*/,
7/*H*/, 8/*I*/, 9/*J*/, 10/*K*/, 11/*L*/, 12/*M*/, 13/*N*/, 14/*O*/,
15/*P*/, 16/*Q*/, 17/*R*/, 18/*S*/, 19/*T*/, 20/*U*/, 21/*V*/, 22/*W*/,
23/*X*/, 24/*Y*/, 25/*Z*/, 99, 99, 99, 99, 63/*_*/,
99, 26/*a*/, 27/*b*/, 28/*c*/, 29/*d*/, 30/*e*/, 31/*f*/, 32/*g*/,
33/*h*/, 34/*i*/, 35/*j*/, 36/*k*/, 37/*l*/, 38/*m*/, 39/*n*/, 40/*o*/,
41/*p*/, 42/*q*/, 43/*r*/, 44/*s*/, 45/*t*/, 46/*u*/, 47/*v*/, 48/*w*/,
49/*x*/, 50/*y*/, 51/*z*/, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
};
// Tests a charact to see if it's a whitespace character.
//
// Returns:
// YES if the character is a whitespace character.
// NO if the character is not a whitespace character.
//
FOUNDATION_STATIC_INLINE BOOL IsSpace(unsigned char c) {
// we use our own mapping here because we don't want anything w/ locale
// support.
static BOOL kSpaces[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 1, // 0-9
1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 10-19
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20-29
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, // 30-39
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40-49
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 50-59
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60-69
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 70-79
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 80-89
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 90-99
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 100-109
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 110-119
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 120-129
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 130-139
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 140-149
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 150-159
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 160-169
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 170-179
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 180-189
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 190-199
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 200-209
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 210-219
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 220-229
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 230-239
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 240-249
0, 0, 0, 0, 0, 1, // 250-255
};
return kSpaces[c];
}
// Calculate how long the data will be once it's base64 encoded.
//
// Returns:
// The guessed encoded length for a source length
//
FOUNDATION_STATIC_INLINE NSUInteger CalcEncodedLength(NSUInteger srcLen,
BOOL padded) {
NSUInteger intermediate_result = 8 * srcLen + 5;
NSUInteger len = intermediate_result / 6;
if (padded) {
len = ((len + 3) / 4) * 4;
}
return len;
}
// Tries to calculate how long the data will be once it's base64 decoded.
// Unlinke the above, this is always an upperbound, since the source data
// could have spaces and might end with the padding characters on them.
//
// Returns:
// The guessed decoded length for a source length
//
FOUNDATION_STATIC_INLINE NSUInteger GuessDecodedLength(NSUInteger srcLen) {
return (srcLen + 3) / 4 * 3;
}
@interface GTMBase64 (PrivateMethods)
+(NSData *)baseEncode:(const void *)bytes
length:(NSUInteger)length
charset:(const char *)charset
padded:(BOOL)padded;
+(NSData *)baseDecode:(const void *)bytes
length:(NSUInteger)length
charset:(const char*)charset
requirePadding:(BOOL)requirePadding;
+(NSUInteger)baseEncode:(const char *)srcBytes
srcLen:(NSUInteger)srcLen
destBytes:(char *)destBytes
destLen:(NSUInteger)destLen
charset:(const char *)charset
padded:(BOOL)padded;
+(NSUInteger)baseDecode:(const char *)srcBytes
srcLen:(NSUInteger)srcLen
destBytes:(char *)destBytes
destLen:(NSUInteger)destLen
charset:(const char *)charset
requirePadding:(BOOL)requirePadding;
@end
@implementation GTMBase64
//
// Standard Base64 (RFC) handling
//
+(NSData *)encodeData:(NSData *)data {
return [self baseEncode:[data bytes]
length:[data length]
charset:kBase64EncodeChars
padded:YES];
}
+(NSData *)decodeData:(NSData *)data {
return [self baseDecode:[data bytes]
length:[data length]
charset:kBase64DecodeChars
requirePadding:YES];
}
+(NSData *)encodeBytes:(const void *)bytes length:(NSUInteger)length {
return [self baseEncode:bytes
length:length
charset:kBase64EncodeChars
padded:YES];
}
+(NSData *)decodeBytes:(const void *)bytes length:(NSUInteger)length {
return [self baseDecode:bytes
length:length
charset:kBase64DecodeChars
requirePadding:YES];
}
+(NSString *)stringByEncodingData:(NSData *)data {
NSString *result = nil;
NSData *converted = [self baseEncode:[data bytes]
length:[data length]
charset:kBase64EncodeChars
padded:YES];
if (converted) {
result = [[[NSString alloc] initWithData:converted
encoding:NSASCIIStringEncoding] autorelease];
}
return result;
}
+(NSString *)stringByEncodingBytes:(const void *)bytes length:(NSUInteger)length {
NSString *result = nil;
NSData *converted = [self baseEncode:bytes
length:length
charset:kBase64EncodeChars
padded:YES];
if (converted) {
result = [[[NSString alloc] initWithData:converted
encoding:NSASCIIStringEncoding] autorelease];
}
return result;
}
+(NSData *)decodeString:(NSString *)string {
NSData *result = nil;
NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
if (data) {
result = [self baseDecode:[data bytes]
length:[data length]
charset:kBase64DecodeChars
requirePadding:YES];
}
return result;
}
//
// Modified Base64 encoding so the results can go onto urls.
//
// The changes are in the characters generated and also the result isn't
// padded to a multiple of 4.
// Must use the matching call to encode/decode, won't interop with the
// RFC versions.
//
+(NSData *)webSafeEncodeData:(NSData *)data
padded:(BOOL)padded {
return [self baseEncode:[data bytes]
length:[data length]
charset:kWebSafeBase64EncodeChars
padded:padded];
}
+(NSData *)webSafeDecodeData:(NSData *)data {
return [self baseDecode:[data bytes]
length:[data length]
charset:kWebSafeBase64DecodeChars
requirePadding:NO];
}
+(NSData *)webSafeEncodeBytes:(const void *)bytes
length:(NSUInteger)length
padded:(BOOL)padded {
return [self baseEncode:bytes
length:length
charset:kWebSafeBase64EncodeChars
padded:padded];
}
+(NSData *)webSafeDecodeBytes:(const void *)bytes length:(NSUInteger)length {
return [self baseDecode:bytes
length:length
charset:kWebSafeBase64DecodeChars
requirePadding:NO];
}
+(NSString *)stringByWebSafeEncodingData:(NSData *)data
padded:(BOOL)padded {
NSString *result = nil;
NSData *converted = [self baseEncode:[data bytes]
length:[data length]
charset:kWebSafeBase64EncodeChars
padded:padded];
if (converted) {
result = [[[NSString alloc] initWithData:converted
encoding:NSASCIIStringEncoding] autorelease];
}
return result;
}
+(NSString *)stringByWebSafeEncodingBytes:(const void *)bytes
length:(NSUInteger)length
padded:(BOOL)padded {
NSString *result = nil;
NSData *converted = [self baseEncode:bytes
length:length
charset:kWebSafeBase64EncodeChars
padded:padded];
if (converted) {
result = [[[NSString alloc] initWithData:converted
encoding:NSASCIIStringEncoding] autorelease];
}
return result;
}
+(NSData *)webSafeDecodeString:(NSString *)string {
NSData *result = nil;
NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
if (data) {
result = [self baseDecode:[data bytes]
length:[data length]
charset:kWebSafeBase64DecodeChars
requirePadding:NO];
}
return result;
}
@end
@implementation GTMBase64 (PrivateMethods)
//
// baseEncode:length:charset:padded:
//
// Does the common lifting of creating the dest NSData. it creates & sizes the
// data for the results. |charset| is the characters to use for the encoding
// of the data. |padding| controls if the encoded data should be padded to a
// multiple of 4.
//
// Returns:
// an autorelease NSData with the encoded data, nil if any error.
//
+(NSData *)baseEncode:(const void *)bytes
length:(NSUInteger)length
charset:(const char *)charset
padded:(BOOL)padded {
// how big could it be?
NSUInteger maxLength = CalcEncodedLength(length, padded);
// make space
NSMutableData *result = [NSMutableData data];
[result setLength:maxLength];
// do it
NSUInteger finalLength = [self baseEncode:bytes
srcLen:length
destBytes:[result mutableBytes]
destLen:[result length]
charset:charset
padded:padded];
if (finalLength) {
_GTMDevAssert(finalLength == maxLength, @"how did we calc the length wrong?");
} else {
// shouldn't happen, this means we ran out of space
result = nil;
}
return result;
}
//
// baseDecode:length:charset:requirePadding:
//
// Does the common lifting of creating the dest NSData. it creates & sizes the
// data for the results. |charset| is the characters to use for the decoding
// of the data.
//
// Returns:
// an autorelease NSData with the decoded data, nil if any error.
//
//
+(NSData *)baseDecode:(const void *)bytes
length:(NSUInteger)length
charset:(const char *)charset
requirePadding:(BOOL)requirePadding {
// could try to calculate what it will end up as
NSUInteger maxLength = GuessDecodedLength(length);
// make space
NSMutableData *result = [NSMutableData data];
[result setLength:maxLength];
// do it
NSUInteger finalLength = [self baseDecode:bytes
srcLen:length
destBytes:[result mutableBytes]
destLen:[result length]
charset:charset
requirePadding:requirePadding];
if (finalLength) {
if (finalLength != maxLength) {
// resize down to how big it was
[result setLength:finalLength];
}
} else {
// either an error in the args, or we ran out of space
result = nil;
}
return result;
}
//
// baseEncode:srcLen:destBytes:destLen:charset:padded:
//
// Encodes the buffer into the larger. returns the length of the encoded
// data, or zero for an error.
// |charset| is the characters to use for the encoding
// |padded| tells if the result should be padded to a multiple of 4.
//
// Returns:
// the length of the encoded data. zero if any error.
//
+(NSUInteger)baseEncode:(const char *)srcBytes
srcLen:(NSUInteger)srcLen
destBytes:(char *)destBytes
destLen:(NSUInteger)destLen
charset:(const char *)charset
padded:(BOOL)padded {
if (!srcLen || !destLen || !srcBytes || !destBytes) {
return 0;
}
char *curDest = destBytes;
const unsigned char *curSrc = (const unsigned char *)(srcBytes);
// Three bytes of data encodes to four characters of cyphertext.
// So we can pump through three-byte chunks atomically.
while (srcLen > 2) {
// space?
_GTMDevAssert(destLen >= 4, @"our calc for encoded length was wrong");
curDest[0] = charset[curSrc[0] >> 2];
curDest[1] = charset[((curSrc[0] & 0x03) << 4) + (curSrc[1] >> 4)];
curDest[2] = charset[((curSrc[1] & 0x0f) << 2) + (curSrc[2] >> 6)];
curDest[3] = charset[curSrc[2] & 0x3f];
curDest += 4;
curSrc += 3;
srcLen -= 3;
destLen -= 4;
}
// now deal with the tail (<=2 bytes)
switch (srcLen) {
case 0:
// Nothing left; nothing more to do.
break;
case 1:
// One byte left: this encodes to two characters, and (optionally)
// two pad characters to round out the four-character cypherblock.
_GTMDevAssert(destLen >= 2, @"our calc for encoded length was wrong");
curDest[0] = charset[curSrc[0] >> 2];
curDest[1] = charset[(curSrc[0] & 0x03) << 4];
curDest += 2;
destLen -= 2;
if (padded) {
_GTMDevAssert(destLen >= 2, @"our calc for encoded length was wrong");
curDest[0] = kBase64PaddingChar;
curDest[1] = kBase64PaddingChar;
curDest += 2;
destLen -= 2;
}
break;
case 2:
// Two bytes left: this encodes to three characters, and (optionally)
// one pad character to round out the four-character cypherblock.
_GTMDevAssert(destLen >= 3, @"our calc for encoded length was wrong");
curDest[0] = charset[curSrc[0] >> 2];
curDest[1] = charset[((curSrc[0] & 0x03) << 4) + (curSrc[1] >> 4)];
curDest[2] = charset[(curSrc[1] & 0x0f) << 2];
curDest += 3;
destLen -= 3;
if (padded) {
_GTMDevAssert(destLen >= 1, @"our calc for encoded length was wrong");
curDest[0] = kBase64PaddingChar;
curDest += 1;
destLen -= 1;
}
break;
}
// return the length
return (curDest - destBytes);
}
//
// baseDecode:srcLen:destBytes:destLen:charset:requirePadding:
//
// Decodes the buffer into the larger. returns the length of the decoded
// data, or zero for an error.
// |charset| is the character decoding buffer to use
//
// Returns:
// the length of the encoded data. zero if any error.
//
+(NSUInteger)baseDecode:(const char *)srcBytes
srcLen:(NSUInteger)srcLen
destBytes:(char *)destBytes
destLen:(NSUInteger)destLen
charset:(const char *)charset
requirePadding:(BOOL)requirePadding {
if (!srcLen || !destLen || !srcBytes || !destBytes) {
return 0;
}
int decode;
NSUInteger destIndex = 0;
int state = 0;
char ch = 0;
while (srcLen-- && (ch = *srcBytes++) != 0) {
if (IsSpace(ch)) // Skip whitespace
continue;
if (ch == kBase64PaddingChar)
break;
decode = charset[(unsigned int)ch];
if (decode == kBase64InvalidChar)
return 0;
// Four cyphertext characters decode to three bytes.
// Therefore we can be in one of four states.
switch (state) {
case 0:
// We're at the beginning of a four-character cyphertext block.
// This sets the high six bits of the first byte of the
// plaintext block.
_GTMDevAssert(destIndex < destLen, @"our calc for decoded length was wrong");
destBytes[destIndex] = decode << 2;
state = 1;
break;
case 1:
// We're one character into a four-character cyphertext block.
// This sets the low two bits of the first plaintext byte,
// and the high four bits of the second plaintext byte.
_GTMDevAssert((destIndex+1) < destLen, @"our calc for decoded length was wrong");
destBytes[destIndex] |= decode >> 4;
destBytes[destIndex+1] = (decode & 0x0f) << 4;
destIndex++;
state = 2;
break;
case 2:
// We're two characters into a four-character cyphertext block.
// This sets the low four bits of the second plaintext
// byte, and the high two bits of the third plaintext byte.
// However, if this is the end of data, and those two
// bits are zero, it could be that those two bits are
// leftovers from the encoding of data that had a length
// of two mod three.
_GTMDevAssert((destIndex+1) < destLen, @"our calc for decoded length was wrong");
destBytes[destIndex] |= decode >> 2;
destBytes[destIndex+1] = (decode & 0x03) << 6;
destIndex++;
state = 3;
break;
case 3:
// We're at the last character of a four-character cyphertext block.
// This sets the low six bits of the third plaintext byte.
_GTMDevAssert(destIndex < destLen, @"our calc for decoded length was wrong");
destBytes[destIndex] |= decode;
destIndex++;
state = 0;
break;
}
}
// We are done decoding Base-64 chars. Let's see if we ended
// on a byte boundary, and/or with erroneous trailing characters.
if (ch == kBase64PaddingChar) { // We got a pad char
if ((state == 0) || (state == 1)) {
return 0; // Invalid '=' in first or second position
}
if (srcLen == 0) {
if (state == 2) { // We run out of input but we still need another '='
return 0;
}
// Otherwise, we are in state 3 and only need this '='
} else {
if (state == 2) { // need another '='
while ((ch = *srcBytes++) && (srcLen-- > 0)) {
if (!IsSpace(ch))
break;
}
if (ch != kBase64PaddingChar) {
return 0;
}
}
// state = 1 or 2, check if all remain padding is space
while ((ch = *srcBytes++) && (srcLen-- > 0)) {
if (!IsSpace(ch)) {
return 0;
}
}
}
} else {
// We ended by seeing the end of the string.
if (requirePadding) {
// If we require padding, then anything but state 0 is an error.
if (state != 0) {
return 0;
}
} else {
// Make sure we have no partial bytes lying around. Note that we do not
// require trailing '=', so states 2 and 3 are okay too.
if (state == 1) {
return 0;
}
}
}
// If then next piece of output was valid and got written to it means we got a
// very carefully crafted input that appeared valid but contains some trailing
// bits past the real length, so just toss the thing.
if ((destIndex < destLen) &&
(destBytes[destIndex] != 0)) {
return 0;
}
return destIndex;
}
@end
在Base64 代码中用到了一个.h文件
Defines.h
//
// GTMDefines.h
//
// Copyright 2008 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy
// of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
//
// ============================================================================
#include <AvailabilityMacros.h>
// Not all MAC_OS_X_VERSION_10_X macros defined in past SDKs
#ifndef MAC_OS_X_VERSION_10_5
#define MAC_OS_X_VERSION_10_5 1050
#endif
#ifndef MAC_OS_X_VERSION_10_6
#define MAC_OS_X_VERSION_10_6 1060
#endif
// ----------------------------------------------------------------------------
// CPP symbols that can be overridden in a prefix to control how the toolbox
// is compiled.
// ----------------------------------------------------------------------------
// GTMHTTPFetcher will support logging by default but only hook its input
// stream support for logging when requested. You can control the inclusion of
// the code by providing your own definitions for these w/in a prefix header.
//
#ifndef GTM_HTTPFETCHER_ENABLE_LOGGING
#define GTM_HTTPFETCHER_ENABLE_LOGGING 1
#endif // GTM_HTTPFETCHER_ENABLE_LOGGING
#ifndef GTM_HTTPFETCHER_ENABLE_INPUTSTREAM_LOGGING
#define GTM_HTTPFETCHER_ENABLE_INPUTSTREAM_LOGGING 0
#endif // GTM_HTTPFETCHER_ENABLE_INPUTSTREAM_LOGGING
// By setting the GTM_CONTAINERS_VALIDATION_FAILED_LOG and
// GTM_CONTAINERS_VALIDATION_FAILED_ASSERT macros you can control what happens
// when a validation fails. If you implement your own validators, you may want
// to control their internals using the same macros for consistency.
#ifndef GTM_CONTAINERS_VALIDATION_FAILED_ASSERT
#define GTM_CONTAINERS_VALIDATION_FAILED_ASSERT 0
#endif
// Give ourselves a consistent way to do inlines. Apple's macros even use
// a few different actual definitions, so we're based off of the foundation
// one.
#if !defined(GTM_INLINE)
#if defined (__GNUC__) && (__GNUC__ == 4)
#define GTM_INLINE static __inline__ __attribute__((always_inline))
#else
#define GTM_INLINE static __inline__
#endif
#endif
// Give ourselves a consistent way of doing externs that links up nicely
// when mixing objc and objc++
#if !defined (GTM_EXTERN)
#if defined __cplusplus
#define GTM_EXTERN extern "C"
#else
#define GTM_EXTERN extern
#endif
#endif
// Give ourselves a consistent way of exporting things if we have visibility
// set to hidden.
#if !defined (GTM_EXPORT)
#define GTM_EXPORT __attribute__((visibility("default")))
#endif
// _GTMDevLog & _GTMDevAssert
//
// _GTMDevLog & _GTMDevAssert are meant to be a very lightweight shell for
// developer level errors. This implementation simply macros to NSLog/NSAssert.
// It is not intended to be a general logging/reporting system.
//
// Please see http://code.google.com/p/google-toolbox-for-mac/wiki/DevLogNAssert
// for a little more background on the usage of these macros.
//
// _GTMDevLog log some error/problem in debug builds
// _GTMDevAssert assert if conditon isn't met w/in a method/function
// in all builds.
//
// To replace this system, just provide different macro definitions in your
// prefix header. Remember, any implementation you provide *must* be thread
// safe since this could be called by anything in what ever situtation it has
// been placed in.
//
// We only define the simple macros if nothing else has defined this.
#ifndef _GTMDevLog
#ifdef DEBUG
#define _GTMDevLog(...) NSLog(__VA_ARGS__)
#else
#define _GTMDevLog(...) do { } while (0)
#endif
#endif // _GTMDevLog
// Declared here so that it can easily be used for logging tracking if
// necessary. See GTMUnitTestDevLog.h for details.
@class NSString;
GTM_EXTERN void _GTMUnitTestDevLog(NSString *format, ...);
#ifndef _GTMDevAssert
// we directly invoke the NSAssert handler so we can pass on the varargs
// (NSAssert doesn't have a macro we can use that takes varargs)
#if !defined(NS_BLOCK_ASSERTIONS)
#define _GTMDevAssert(condition, ...) \
do { \
if (!(condition)) { \
[[NSAssertionHandler currentHandler] \
handleFailureInFunction:[NSString stringWithUTF8String:__PRETTY_FUNCTION__] \
file:[NSString stringWithUTF8String:__FILE__] \
lineNumber:__LINE__ \
description:__VA_ARGS__]; \
} \
} while(0)
#else // !defined(NS_BLOCK_ASSERTIONS)
#define _GTMDevAssert(condition, ...) do { } while (0)
#endif // !defined(NS_BLOCK_ASSERTIONS)
#endif // _GTMDevAssert
// _GTMCompileAssert
// _GTMCompileAssert is an assert that is meant to fire at compile time if you
// want to check things at compile instead of runtime. For example if you
// want to check that a wchar is 4 bytes instead of 2 you would use
// _GTMCompileAssert(sizeof(wchar_t) == 4, wchar_t_is_4_bytes_on_OS_X)
// Note that the second "arg" is not in quotes, and must be a valid processor
// symbol in it's own right (no spaces, punctuation etc).
// Wrapping this in an #ifndef allows external groups to define their own
// compile time assert scheme.
#ifndef _GTMCompileAssert
// We got this technique from here:
// http://unixjunkie.blogspot.com/2007/10/better-compile-time-asserts_29.html
#define _GTMCompileAssertSymbolInner(line, msg) _GTMCOMPILEASSERT ## line ## __ ## msg
#define _GTMCompileAssertSymbol(line, msg) _GTMCompileAssertSymbolInner(line, msg)
#define _GTMCompileAssert(test, msg) \
typedef char _GTMCompileAssertSymbol(__LINE__, msg) [ ((test) ? 1 : -1) ]
#endif // _GTMCompileAssert
// Macro to allow fast enumeration when building for 10.5 or later, and
// reliance on NSEnumerator for 10.4. Remember, NSDictionary w/ FastEnumeration
// does keys, so pick the right thing, nothing is done on the FastEnumeration
// side to be sure you're getting what you wanted.
#ifndef GTM_FOREACH_OBJECT
#if defined(TARGET_OS_IPHONE) || (MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_5)
#define GTM_FOREACH_OBJECT(element, collection) \
for (element in collection)
#define GTM_FOREACH_KEY(element, collection) \
for (element in collection)
#else
#define GTM_FOREACH_OBJECT(element, collection) \
for (NSEnumerator * _ ## element ## _enum = [collection objectEnumerator]; \
(element = [_ ## element ## _enum nextObject]) != nil; )
#define GTM_FOREACH_KEY(element, collection) \
for (NSEnumerator * _ ## element ## _enum = [collection keyEnumerator]; \
(element = [_ ## element ## _enum nextObject]) != nil; )
#endif
#endif
// ============================================================================
// ----------------------------------------------------------------------------
// CPP symbols defined based on the project settings so the GTM code has
// simple things to test against w/o scattering the knowledge of project
// setting through all the code.
// ----------------------------------------------------------------------------
// Provide a single constant CPP symbol that all of GTM uses for ifdefing
// iPhone code.
#include <TargetConditionals.h>
#if TARGET_OS_IPHONE // iPhone SDK
// For iPhone specific stuff
#define GTM_IPHONE_SDK 1
#if TARGET_IPHONE_SIMULATOR
#define GTM_IPHONE_SIMULATOR 1
#else
#define GTM_IPHONE_DEVICE 1
#endif // TARGET_IPHONE_SIMULATOR
#else
// For MacOS specific stuff
#define GTM_MACOS_SDK 1
#endif
// Provide a symbol to include/exclude extra code for GC support. (This mainly
// just controls the inclusion of finalize methods).
#ifndef GTM_SUPPORT_GC
#if GTM_IPHONE_SDK
// iPhone never needs GC
#define GTM_SUPPORT_GC 0
#else
// We can't find a symbol to tell if GC is supported/required, so best we
// do on Mac targets is include it if we're on 10.5 or later.
#if MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4
#define GTM_SUPPORT_GC 0
#else
#define GTM_SUPPORT_GC 1
#endif
#endif
#endif
// To simplify support for 64bit (and Leopard in general), we provide the type
// defines for non Leopard SDKs
#if MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4
// NSInteger/NSUInteger and Max/Mins
#ifndef NSINTEGER_DEFINED
#if __LP64__ || NS_BUILD_32_LIKE_64
typedef long NSInteger;
typedef unsigned long NSUInteger;
#else
typedef int NSInteger;
typedef unsigned int NSUInteger;
#endif
#define NSIntegerMax LONG_MAX
#define NSIntegerMin LONG_MIN
#define NSUIntegerMax ULONG_MAX
#define NSINTEGER_DEFINED 1
#endif // NSINTEGER_DEFINED
// CGFloat
#ifndef CGFLOAT_DEFINED
#if defined(__LP64__) && __LP64__
// This really is an untested path (64bit on Tiger?)
typedef double CGFloat;
#define CGFLOAT_MIN DBL_MIN
#define CGFLOAT_MAX DBL_MAX
#define CGFLOAT_IS_DOUBLE 1
#else /* !defined(__LP64__) || !__LP64__ */
typedef float CGFloat;
#define CGFLOAT_MIN FLT_MIN
#define CGFLOAT_MAX FLT_MAX
#define CGFLOAT_IS_DOUBLE 0
#endif /* !defined(__LP64__) || !__LP64__ */
#define CGFLOAT_DEFINED 1
#endif // CGFLOAT_DEFINED
#endif // MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4
调用方法测试：
NSString *encrypt = [ViewController encryptWithText:@"中华人民共和国万岁！！"];
NSLog(@"enctry = %@",encrypt);
NSString *decrypt = [ViewController decryptWithText:encrypt];
NSLog(@"decrypt = %@",decrypt);
输出结果：
enctry = IKnyVPAK8eprKHHunG7Ze9tTfU8sIoYho8SFeyFEniK/7wy3u7stKA==
decrypt =中华人民共和国万岁！！