iOS常用加密算法详解手机开发

    //   
    //  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。

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

    //   
    //  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