iOS加密解密算法

最近项目中对接微软小冰的业务,大厂都对内部的资源有相当的保密措施,对给到第三方的数据都是加密的,下面是应用到的相关的加密解密函数:异或加密解密及base64的加密解密

异或加密算法

static NSString *secretKey =@"XiaoBing_Qitianzhen";
/**
 *  异或加密算法
 *
 *  @param sourceData 需要加密的字节流
 *  @param key        加密的key
 *
 *  @return 加密后的字节流
 */
- (NSString *)encryptForPlainText:(NSString *)plainText
{
    //保存加密后的字符
    NSMutableString *encryption=[NSMutableString string];
    //编码转换后的字符串 UTF_8->iso-8859-1
    NSString *encoding=[[NSString alloc]initWithData:[plainText dataUsingEncoding:NSUTF8StringEncoding] encoding:NSISOLatin1StringEncoding];
    
    for(int i=0,j=0;i<encoding.length;i++,j++){
        if(j==secretKey.length){
            j=0;
        }
        //异或后的字符
        char cipher=(char)([encoding characterAtIndex:i]^[secretKey characterAtIndex:j]);
        //NSLog(@"%c转成16进制的字符串：%@,%@",cipher,[NSString stringWithFormat:@"%hhx",cipher],[NSString stringWithFormat:@"%x",cipher&0xff]);
        //转成16进制形式的字符串 \x8b转成8b字符串
        NSString *strCipher= [NSString stringWithFormat:@"%hhx",cipher];
        if(strCipher.length == 1){
            [encryption appendFormat:@"0%@",strCipher];
        }else{
            [encryption appendString:strCipher];
        }
    }
    return encryption;
}

异或解密

- (NSString *)decryptForEncryption:(NSString *)encryption {
    //保存解密后的字符
    NSMutableString *decryption=[NSMutableString string];
    //解码字符
    NSString *decoding=nil;
    
    for(int i=0,j=0;i<encryption.length/2;i++,j++){
        if(j==secretKey.length){
            j=0;
        }
        //截取16进制形式的字符串 \x8b中的8b
        NSString *tem=[encryption substringWithRange:NSMakeRange(i*2, 2)];
        char *endptr;
        //把16进制形式的字符串转为字符
        char n=(char)(int)strtoul([tem UTF8String],&endptr,16);
        //判断是否为加密字符
        if (n=='\0'&&*endptr!='\0') {
            [decryption setString:@""];
            break;
        }
        [decryption appendFormat:@"%c",(char)(n^[secretKey characterAtIndex:j])];
    }
    if (![decryption isEqualToString:@""]) {
        //编码后的字符串 iso-8859-1 -> UTF_8
        decoding=[[NSString alloc]initWithData:[[decryption copy] dataUsingEncoding:NSISOLatin1StringEncoding] encoding:NSUTF8StringEncoding];
    }
    if (decoding==nil) {
        decoding=encryption;
    }
    return decoding;
}

base64的加密解密

//把字符串转成Base64编码
- (NSString *)base64EncodeString:(NSString *)string
{
    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
    
    return [data base64EncodedStringWithOptions:0];
}

//字符串解码
- (NSString *)stringEncodeBase64:(NSString *)encodeStr
{
    NSData *nsdataFromBase64String = [[NSData alloc] initWithBase64EncodedString:encodeStr options:0];
    
    NSString *base64Decoded = [[NSString alloc]initWithData:nsdataFromBase64String encoding:NSUTF8StringEncoding];

    return base64Decoded;
}

此文只为记录笔记,以后查阅方便!有哪些写的不对的地方,欢迎指正!!!