public RSA(Random random) { savedRandom = random; p = getPrime(random); // p and q are arbitrary large primes q = getPrime(random); n = p.multiply(q); phiN = (p.subtract(ONE)).multiply(q.subtract(ONE)); S = getPrime(random); // s is an arbitrary secret; we'll use a prime V = S.modPow(new BigInteger("2"), n); }
private void makeKeys() { PrimeGenerator pg = new PrimeGenerator(513, 10, sr); do { p = pg.getStrongPrime(); } while (p.subtract(BigIntegerMath.ONE).mod(BigIntegerMath.THREE).equals(BigIntegerMath.ZERO)); do { q = pg.getStrongPrime(); } while (q.subtract(BigIntegerMath.ONE).mod(BigIntegerMath.THREE).equals(BigIntegerMath.ZERO)); modulus = p.multiply(q); // Use 3 as enciphering exponent - OK since we are using salt decipherExp = BigIntegerMath.THREE.modInverse( p.subtract(BigIntegerMath.ONE).multiply(q.subtract(BigIntegerMath.ONE))); ciphertextBlockSize = (modulus.bitLength() - 1) / 8 + 1; // Maximum size of plaintext is 6 bytes less than ciphertext // 1 to get under modulus // 4 for the salt // 1 for a pad byte plaintextBlockSize = ciphertextBlockSize - 6; }
void start() throws IOException { BigInteger n = new BigInteger(reader.next()); String s = reader.next(); BigInteger answer = BigInteger.ONE; while (n.compareTo(BigInteger.ONE) > 0) { answer = answer.multiply(n); n = n.subtract(BigInteger.valueOf(s.length())); } writer.println(answer); }
void solve(int caseNum) { int n = in.nextInt(); BigInteger[] past = new BigInteger[n], d = new BigInteger[n]; for (int i = 0; i < n; i++) past[i] = new BigInteger(in.next()); Arrays.sort(past); for (int i = 0; i < n; i++) d[i] = past[i].subtract(past[0]); for (int i = 2; i < n; i++) d[i] = d[i].gcd(d[i - 1]); BigInteger gcd = d[n - 1], mod = past[0].mod(gcd); System.out.printf("Case #%d: ", caseNum); if (mod.equals(BigInteger.ZERO)) System.out.println(0); else System.out.println(gcd.subtract(mod)); }