RSA原理模拟
static int P = 11;
static int Q = 13;
static int N;
static int M;
static int E;
static int D;
- (instancetype)init
{
self = [super init];
if (self) {
N = P * Q;
M = (P - 1) * (Q - 1);
NSLog(@"N:%zd - M:%zd", N, M);
E = 89;
for (int i = 1; i < INT_MAX; i++) {
if ((i * E) % M == 1 && (i != E)) {
D = i;
break;
}
}
NSLog(@"E:%zd - D:%zd", E, D);
}
return self;
}
- (NSString *)encryptString:(NSString *)string
{
// 1. 将字符串转换成NSData
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
NSLog(@"要加密的二进制数据: %@", data);
NSMutableString *strM = [NSMutableString string];
// 2. 取出字符串中的每一个字符
for (int i = 0; i < data.length; i++) {
unsigned char c = 0;
[data getBytes:&c range:NSMakeRange(i, 1)];
int result = 1;
// 3. (c ^ E) % N，为了防止溢出，采用循环取模的方式计算
for (int k = 0; k < E; k++) {
result = result * c % N;
}
printf("%02d ", result);
// 4. 拼接加密字符串
[strM appendFormat:@"%c", result];
}
printf("\n");
return [strM copy];
}
- (NSString *)decryptString:(NSString *)string
{
// 1. 将字符串转换成NSData
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
NSLog(@"要解密的二进制数据: %@", data);
NSMutableString *strM = [NSMutableString string];
// 2. 取出字符串中的每一个字符
for (int i = 0; i < data.length; i++) {
unsigned char c = 0;
[data getBytes:&c range:NSMakeRange(i, 1)];
int result = 1;
// 3. (c ^ D) % N，为了防止溢出，采用循环取模的方式计算
for (int k = 0; k < D; k++) {
result = result * c % N;
}
// 4. 拼接加密字符串
[strM appendFormat:@"%c", result];
}
printf("\n");
return [strM copy];
}
/** 判断一个数字是否为质数 */
+ (BOOL)isPrime:(int)n
{
if (n == 0 || n == 1 ) {
return NO;
}
int k = (int)sqrt(n);
int i = 2;
for (; i <= k; i++) {
if (n % i == 0) break;
}
return (i > k);
}
@end
