[iOS]AES加密在iOS上面的实现

Encryption.h文件

 

 

#import <Foundation/Foundation.h> @class NSString; @interface NSData (Encryption) - (NSData *)AES256EncryptWithKey:(NSString *)key;   //加密- (NSData *)AES256DecryptWithKey:(NSString *)key;   //解密- (NSString *)newStringInBase64FromData;            //追加64编码+ (NSString*)base64encode:(NSString*)str;           //同上64编码 @end

 

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Encryption.m文件

 

#import "Encryption.h"#import <CommonCrypto/CommonCryptor.h>  static char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; @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;}  - (NSString *)newStringInBase64FromData            //追加64编码{    NSMutableString *dest = [[NSMutableString alloc] initWithString:@""];    unsigned char * working = (unsigned char *)[self bytes];    int srcLen = [self length];    for (int i=0; i<srcLen; i += 3) {        for (int nib=0; nib<4; nib++) {            int byt = (nib == 0)?0:nib-1;            int ix = (nib+1)*2;            if (i+byt >= srcLen) break;            unsigned char curr = ((working[i+byt] << (8-ix)) & 0x3F);            if (i+nib < srcLen) curr |= ((working[i+nib] >> ix) & 0x3F);            [dest appendFormat:@"%c", base64[curr]];        }    }    return dest;} + (NSString*)base64encode:(NSString*)str{    if ([str length] == 0)        return @"";    const char *source = [str UTF8String];    int strlength  = strlen(source);    char *characters = malloc(((strlength + 2) / 3) * 4);    if (characters == NULL)        return nil;    NSUInteger length = 0;    NSUInteger i = 0;    while (i < strlength) {        char buffer[3] = {0,0,0};        short bufferLength = 0;        while (bufferLength < 3 && i < strlength)            buffer[bufferLength++] = source[i++];        characters[length++] = base64[(buffer[0] & 0xFC) >> 2];        characters[length++] = base64[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];        if (bufferLength > 1)            characters[length++] = base64[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];        else characters[length++] = '=';        if (bufferLength > 2)            characters[length++] = base64[buffer[2] & 0x3F];        else characters[length++] = '=';    }    NSString *g = [[[NSString alloc] initWithBytesNoCopy:characters length:lengthencoding:NSASCIIStringEncoding freeWhenDone:YES] autorelease];    return g;}  @end ------------------------------------------------------------------------------------------------ 测试代码  #import "Encryption.h"        NSString *key = @"my password";    NSString *secret = @"text to encrypt";    //加密    NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];    NSData *cipher = [plain AES256EncryptWithKey:key];    NSLog(@"%@",[[cipher newStringInBase64FromData] autorelease]);    printf("%s\n", [[cipher description] UTF8String]);    NSLog(@"%@", [[[NSString alloc] initWithData:cipher encoding:NSUTF8StringEncoding] autorelease]);//打印出null,这是因为没有解密。    //解密    plain = [cipher AES256DecryptWithKey:key];    printf("%s\n", [[plain description] UTF8String]);    NSLog(@"%@", [[[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding] autorelease]);    //打印出secret的内容,用密码解密过了。如果使用错误的密码，则打印null