48 lines
1.0 KiB
Factor
48 lines
1.0 KiB
Factor
! Copyright (C) 2008 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: math.primes kernel math math.functions namespaces
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sequences accessors ;
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IN: crypto.rsa
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! The private key is the only secret.
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! p,q are two random primes of numbits/2
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! phi = (p-1)(q-1)
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! modulus = p*q
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! public = 65537
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! private = public modinv phi
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TUPLE: rsa modulus private-key public-key ;
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C: <rsa> rsa
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<PRIVATE
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CONSTANT: public-key 65537
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: rsa-primes ( numbits -- p q )
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2/ 2 swap unique-primes first2 ;
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: modulus-phi ( numbits -- n phi )
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#! Loop until phi is not divisible by the public key.
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dup rsa-primes [ * ] 2keep
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[ 1 - ] bi@ *
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dup public-key gcd nip 1 = [
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rot drop
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] [
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2drop modulus-phi
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] if ;
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PRIVATE>
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: generate-rsa-keypair ( numbits -- <rsa> )
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modulus-phi
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public-key over mod-inv +
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public-key <rsa> ;
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: rsa-encrypt ( message rsa -- encrypted )
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[ public-key>> ] [ modulus>> ] bi ^mod ;
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: rsa-decrypt ( encrypted rsa -- message )
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[ private-key>> ] [ modulus>> ] bi ^mod ;
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