57 lines
1.4 KiB
Markdown
57 lines
1.4 KiB
Markdown
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# Diffie Hellman
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Diffie-Hellman key exchange.
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Alice and Bob use Diffie-Hellman key exchange to share secrets. They
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start with prime numbers, pick private keys, generate and share public
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keys, and then generate a shared secret key.
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## Step 0
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The test program supplies prime numbers p and g.
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## Step 1
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Alice picks a private key, a, greater than 1 and less than p. Bob does
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the same to pick a private key b.
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## Step 2
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Alice calculates a public key A.
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A = g**a mod p
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Using the same p and g, Bob similarly calculates a public key B from his
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private key b.
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## Step 3
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Alice and Bob exchange public keys. Alice calculates secret key s.
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s = B**a mod p
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Bob calculates
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s = A**b mod p
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The calculations produce the same result! Alice and Bob now share
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secret s.
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To run the tests simply run the command `go test` in the exercise directory.
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If the test suite contains benchmarks, you can run these with the `-bench`
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flag:
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go test -bench .
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For more detailed info about the Go track see the [help
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page](http://exercism.io/languages/go).
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## Source
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Wikipedia, 1024 bit key from www.cryptopp.com/wiki. [http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange](http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange)
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## Submitting Incomplete Problems
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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