“Just because you're
paranoid doesn't
mean they aren't
after you”
Joseph Heller, Catch-22
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TRUST
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HOW DOES
ENCRYPTION
WORK
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HISTORY
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SYMMETRIC KEY
ENCRYPTION
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Symmetric Key Encryption
a b c d e f g h i j k l m n o p q r s t u v w x y z
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c d e f g h i j k l m n o p q r s t u v w x y z a b
"a secret massage".encrypt
# => "c ugetgv ocuucig"
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Symmetric Key Decryption
c d e f g h i j k l m n o p q r s t u v w x y z a b
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a b c d e f g h i j k l m n o p q r s t u v w x y z
"c ugetgv ocuucig".decrypt
# => "a secret massage"
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???
a b c d e f g h i j k l m n o p q r s t u v w x y z
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n o p q r s t u v w x y z a b c d e f g h i j k l m
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ROT13
a b c d e f g h i j k l m n o p q r s t u v w x y z
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n o p q r s t u v w x y z a b c d e f g h i j k l m
"Hello World".rot13.rot13.rot13.rot13
#=> "Hello World"
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PROBLEM?
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PUBLIC KEY
ENCRYPTION
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Why does RSA work?
e*d = 1 mod ϕ(n)
Public Key: [e,n]
Private Key: [d, n]
def encrypt(message, e, n)
(message ** e) % n
end
def decrypt(message, d, n)
(message ** d) % n
end
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LARGE
numbers
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Encryption with
GPG
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Encryption has
NOTHING
to do with
TRUST
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Cryptographic
signatures
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Signatures have
NOTHING
to do with
TRUST
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There is no
Central Authority
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WEB
of
TRUST
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NOW
WHAT?!
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Not just for comms
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GPG And Your
Business
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So why are we not
using GPG all the
time?
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GnuPG Field Guide
1.Don't panic!
2.Get GPGTools for Mac or brew install gpg2
3.Setup your own keys
4.Exchange and sign keys (with trust)
5.Spread the word!