iOS常用加密方法（aes、md5、base64）

NSData+AES.h文件

    //        //  NSData-AES.h        //  Smile        //        //                #import <Foundation/Foundation.h>                @class NSString;                @interface NSData (Encryption)                - (NSData *)AES256EncryptWithKey:(NSString *)key;   //加密        - (NSData *)AES256DecryptWithKey:(NSString *)key;   //解密                @end  

NSData+AES.m文件

    //        //  NSData-AES.h        //  Smile        //                #import "NSData+AES.h"        #import <CommonCrypto/CommonCryptor.h>                @implementation NSData (Encryption)                - (NSData *)AES256EncryptWithKey:(NSString *)key {//加密            char keyPtr[kCCKeySizeAES256+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 | kCCOptionECBMode,                                                  keyPtr, kCCBlockSizeAES128,                                                  NULL,                                                  [self bytes], dataLength,                                                  buffer, bufferSize,                                                  &numBytesEncrypted);            if (cryptStatus == kCCSuccess) {                return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];            }            free(buffer);            return nil;        }                        - (NSData *)AES256DecryptWithKey:(NSString *)key {//解密            char keyPtr[kCCKeySizeAES256+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 | kCCOptionECBMode,                                                  keyPtr, kCCBlockSizeAES128,                                                  NULL,                                                  [self bytes], dataLength,                                                  buffer, bufferSize,                                                  &numBytesDecrypted);            if (cryptStatus == kCCSuccess) {                return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];            }            free(buffer);            return nil;        }                @end  

这里AES在iOS加过密以后以nsdata的形式存下来，如果想以nsstring形式存储，那么对nsdata进行base64位编码。

首先下载GTMBase64文件，在工程中加入三个文件
GTMDefines.h
GTMBase64.h
GTMBase64.m
你可以在这里找到这三个文件
http://code.google.com/p/google-toolbox-for-mac/source/browse/trunk/Foundation/?r=87

你也可以在下面的demo里面找到这3个文件，demo会完整实现文章里面常用的3种编码方法。

我在此稍微封装一下：

.h文件

    #pragma mark - base64        + (NSString*)encodeBase64String:(NSString *)input;        + (NSString*)decodeBase64String:(NSString *)input;        + (NSString*)encodeBase64Data:(NSData *)data;        + (NSString*)decodeBase64Data:(NSData *)data;  

.m文件

    #pragma mark - base64        + (NSString*)encodeBase64String:(NSString * )input {             NSData *data = [input dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];             data = [GTMBase64 encodeData:data];             NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];             return base64String;        }                + (NSString*)decodeBase64String:(NSString * )input {             NSData *data = [input dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];             data = [GTMBase64 decodeData:data];             NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];             return base64String;        }                 + (NSString*)encodeBase64Data:(NSData *)data {            data = [GTMBase64 encodeData:data];             NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];            return base64String;        }                + (NSString*)decodeBase64Data:(NSData *)data {            data = [GTMBase64 decodeData:data];             NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];            return base64String;        }  

3、MD5加密

NSString+MD5.h文件

 

    //        //  NSString+MD5Encrypt.h        //  Smile        //        //                #import <CommonCrypto/CommonDigest.h>                @interface NSString (MD5)                - (NSString *)md5Encrypt;                @end  

NSString+MD5.m文件

    //        //  NSString+MD5Encrypt.h        //  Smile        //  //                #import "NSString+MD5.h"                @implementation NSString (MD5)                - (NSString *)md5Encrypt {            const char *original_str = [self UTF8String];            unsigned char result[CC_MD5_DIGEST_LENGTH];            CC_MD5(original_str, strlen(original_str), result);            NSMutableString *hash = [NSMutableString string];            for (int i = 0; i < 16; i++)                [hash appendFormat:@"%02X", result[i]];            return [hash lowercaseString];        }                @end