开发中除了常见的RSA加密、MD5加密等,可以实现自动以算法配合加密方法使用,代码如下:
// 自定义加密算法
+ (NSString *)archlyEncryptionAlgorithmWithData:(NSString *)data key:(NSString *)key isDecode:(BOOL)isDecode{
int len = 128;
if (key == nil || key.length == 0) {
key = @"";
}
if (data.length < 1) {
return @"";
}
NSString *md5Key = [key md5Hash];
NSString *keyA = [[md5Key substringToIndex:16] md5Hash];
NSString *keyB = [[md5Key substringFromIndex:16] md5Hash];
NSString *keyC;
if (isDecode == YES) { // 解密
keyC = [data substringToIndex:4];
}else{ // 加密
NSString *nowTime = [self getNowTimeTimestampms];
NSString *md5Time = [nowTime md5Hash];
keyC = [md5Time substringFromIndex:md5Time.length - 4];
}
NSString *cryptkey = [NSString stringWithFormat:@"%@%@",keyA,[[NSString stringWithFormat:@"%@%@",keyA,keyC] md5Hash]];
NSInteger cryptkeyLength = cryptkey.length;
NSString *newData;
if (isDecode == YES) { // 解密
NSString *preparStr = [data substringFromIndex:4];
if (preparStr.length % 4 != 0) {
NSInteger coverLength = 4 - preparStr.length % 4;
for (int i = 0; i < coverLength ; i ++) {
preparStr = [preparStr stringByAppendingString:@"="];
}
}
newData = [preparStr base64Dencode];
}else{ // 加密
NSString *sub = [[[NSString stringWithFormat:@"%@%@",data,keyB] md5Hash] substringToIndex:16];
newData = [NSString stringWithFormat:@"0000000000%@%@",sub,data];
}
NSString *result = @"";
NSMutableArray *box = [NSMutableArray array];
for (int i = 0; i < len; i++) {
[box addObject:@(i)];
}
NSMutableArray *rndkArray = [NSMutableArray array];
for (int i = 0; i < len; i ++) {
unichar c = [cryptkey characterAtIndex:i % cryptkeyLength];
[rndkArray addObject:@([self ascIIToNumber:[NSString stringWithFormat:@"%C",c]])];
}
int j1 = 0;
for (int i = 0; i < len; i ++) {
int boxNum = [box[i] intValue];
int rndkArrayNum = [rndkArray[i] intValue];
j1 = (j1 + boxNum +rndkArrayNum) % len;
[box exchangeObjectAtIndex:i withObjectAtIndex:j1];
}
int a2 = 0;
int j2 = 0;
for (int i = 0; i < newData.length; i ++) {
a2 = (a2 +1) % len;
int boxNum = [box[a2] intValue];
j2 = (j2 + boxNum) % len;
[box exchangeObjectAtIndex:a2 withObjectAtIndex:j2];
unichar c = [newData characterAtIndex:i];
int ASCIIC = [self ascIIToNumber:[NSString stringWithFormat:@"%C",c]];
int value = ([box[a2] intValue] + [box[j2] intValue]) % len;
int boxValue = [box[value] intValue];
int newValue = ASCIIC ^ boxValue;
NSString *charStr = [self numberToASCII:newValue];
result = [NSString stringWithFormat:@"%@%@",result,charStr];
}
if (isDecode == YES) { // 解密
if (result.length < 1) {
NSLog(@"result 为空");
return @"";
}
BOOL bool1 = [[result substringToIndex:10] isEqualToString:@"0000000000"];
BOOL bool2 = [[result substringToIndex:10] intValue] > [[self getNowTimeTimestamp] intValue];
NSString *string1 = [result substringWithRange:NSMakeRange(10, 16)];
NSString *md5Str = [[NSString stringWithFormat:@"%@%@",[result substringFromIndex:26],keyB] md5Hash];
NSString *string2 = [md5Str substringToIndex:16];
BOOL bool3 = [string2 isEqualToString:string1];
if ((bool1 || bool2) && bool3) {
return [result substringFromIndex:26];
}else {
return @"";
}
}else{ // 加密
NSString *baseStr = [[result base64Encode] stringByReplacingOccurrencesOfString:@"=" withString:@""];
return [NSString stringWithFormat:@"%@%@",keyC,baseStr];
}
}
调用的辅助方法如下:
实现NSStirng 分类
- (NSString *)md5Hash {
const char *plain = self.UTF8String;
unsigned char *digest;
digest = malloc(CC_MD5_DIGEST_LENGTH);
CC_MD5(plain, (CC_LONG)strlen(plain), digest);
NSString *encode = [self stringFromBytes:digest length:CC_MD5_DIGEST_LENGTH];
free(digest);
return encode;
}
#pragma mark - Bytes转字符串
/**
字符大小写可以通过修改“%02X”中的x修改,下面采用的是大写X 小写用 x
*/
- (NSString *)stringFromBytes:(uint8_t *)bytes length:(int)length {
NSMutableString *strM = [NSMutableString string];
for (int i = 0; i < length; i++) {
[strM appendFormat:@"%02x", bytes[i]];
}
return [strM copy];
}
// base64编码
- (NSString *)base64Encode{
NSData * body = [self dataUsingEncoding:NSUTF8StringEncoding];
return [body base64EncodedStringWithOptions:0];
}
// base64解码
- (NSString *)base64Dencode
{
NSData *decodeData = [[NSData alloc] initWithBase64EncodedString:self options:0]; //解码
NSString *decodeString = [[NSString alloc] initWithData:decodeData encoding:NSUTF8StringEncoding];
return decodeString;
}
实例方法如下:
// 获取当前时间戳 毫秒
- (NSString *)getNowTimeTimestampms{
NSDate *datenow = [NSDate date];
NSString *timeSp = [NSString stringWithFormat:@"%ld", (long)([datenow timeIntervalSince1970]*1000)];
return timeSp;
}
// 获取当前时间戳 秒
- (NSString *)getNowTimeTimestamp{
NSDate *datenow = [NSDate date];
NSString *timeSp = [NSString stringWithFormat:@"%ld", (long)[datenow timeIntervalSince1970]];
return timeSp;
}
- (int)ascIIToNumber:(NSString *)c{
return [c characterAtIndex:0];
}
- (NSString *)numberToASCII:(int) number{
return [NSString stringWithFormat:@"%C",(unichar)number];
}
同一套算法实现加密解密,data为需要加密或解密字符串,key为盐值(可以为空),isDecode控制加密或解密
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