Module: Rsa::Encrypter

Defined in:
lib/rsa-encrypter.rb,
lib/rsa-encrypter/version.rb

Constant Summary collapse

VERSION = 
"0.2.1"

Class Method Summary collapse

Class Method Details

.decrypt(message, d, n) ⇒ Object 



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# File 'lib/rsa-encrypter.rb', line 73

def self.decrypt(message, d, n)
	m = ""
	message.each do |c|
		m += (c**d % n).to_i.chr
	end	
	return m
end

.encrypt(message, e, n) ⇒ Object 



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# File 'lib/rsa-encrypter.rb', line 49

def self.encrypt(message, e, n)
	byte = []
	ms = []
	crypt = []
	message.each_char do |c|
		byte << c.ord
	end
	byte.each do |b|
		if b.to_s.length < 3
			ms << "0"+b.to_s
		else
			ms << b	
		end	
					
	end	
	

	ms.each do |b|
		crypt << c = b.to_i**e % n
	end

	return crypt
end

.generate_rsa(a = 5) ⇒ Object 



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# File 'lib/rsa-encrypter.rb', line 34

def self.generate_rsa(a=5)
	secure = [ [11,13], [61,53], [71,76], [163,181], [443,463], [859,769], [1033,977] ]
	a-=1
	raise "wrong secure level: #{a+1}  please use level 1-7" if a > 6 or a < 0
	p = prime?(secure[a][0])
	q = prime?(secure[a][1])
	n = p * q
	n2 = (p-1)*(q-1)
	e = (p+q) -1 
	t = ggt(e, n2)
	d = t 
	rsa = [n, e, d]
	return rsa
end

.ggt(a, b) ⇒ Object 



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# File 'lib/rsa-encrypter.rb', line 5

def self.ggt(a, b)
	u=t=1
	v=s=0
	while b > 0 do
    	q=a/b
    	a, b = b, a-q*b
    	u, s = s, u-q*s
    	v, t = t, v-q*t
	end    
	return u
end

.prime?(x) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rsa-encrypter.rb', line 17

def self.prime?(x)
	if x == 0 or x == 1
		return false
	end

	i = 2
	limit = x / i
	while i < limit
		if x % i == 0
			raise "#{x} not prime"
		end
		i += 1
		limit = x / i
	end
	return x
end