IOS成长之路-DES+Base64 加密、解密
来源：互联网 发布：qq安全中心mac版 编辑：程序博客网 时间：2024/05/21 23:34
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_64typedef long NSInteger;typedef unsigned long NSUInteger;#elsetypedef 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！！
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