35 lines
884 B
Go
35 lines
884 B
Go
package diffiehellman
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import (
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"math/big"
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"math/rand"
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"time"
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)
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// Random number generator
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var rnd = rand.New(rand.NewSource(time.Now().UnixNano()))
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// PrivateKey generates a number greater than 1 and less than p
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func PrivateKey(p *big.Int) *big.Int {
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ret := &big.Int{}
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return ret.Add(big.NewInt(2), ret.Rand(rnd, ret.Sub(p, big.NewInt(2))))
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}
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// PublicKey generates the public key for private key p
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func PublicKey(pKey, p *big.Int, g int64) *big.Int {
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ret := big.NewInt(g)
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return ret.Exp(ret, pKey, p)
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}
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// NewPair generates a public/private key pair from given primes p & g
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func NewPair(p *big.Int, g int64) (*big.Int, *big.Int) {
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priv := PrivateKey(p)
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return priv, PublicKey(priv, p, g)
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}
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// SecretKey returns a secret key given private & public keys and the prime p
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func SecretKey(priv, pub, p *big.Int) *big.Int {
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ret := &big.Int{}
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return ret.Exp(pub, priv, p)
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}
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