Theory and Practice of Cryptography

Google Tech Talks
December, 12 2007

ABSTRACT

Topics include: Introduction to Modern Cryptography, Using Cryptography in Practice, Proofs of Security and Security Definitions and A Special Topic in Cryptography

Speaker: Steve Weis
Steve Weis received his PhD from the Cryptography and Information Security group at MIT, where he was advised by Ron Rivest. He is a member of Google's Applied Security (AppSec) team and is the technical lead for Google's internal cryptographic library, KeyMaster.

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[motionthings]

please try to kill the room mic next time.

[naraithsil]

These tech talks are brilliant.

[klsta]

It's a shame the audio is too poor to listen to.

[NerdInHisShoe]

@wresing Or completely misconstrued as terrorist chatter, landing you and the recipient in Gitmo.

[b1naryd1g1t5]

@lwanatt

It's called public key cryptography. There is a public key and a private key. The public key can be viewed by anyone and is used to send encrypted messages. However, it cannot be used to DECRYPT those messages. Only the private key can do that and no one but the recipient has it. Google has a lot more info. Read up on Diffie-Hellman key exchange and the RSA algorithm.

[n080di]

@StephenWeis Are there efficient ``controlled broadcast'' encryption systems where one would like a group of people to be able to read your messages?

[n080di]

@StephenWeis Why can't RSA-Alice do this?: when Bob gives her m1 and m2, she flips a coin and if it returns i, she xors mi with an encrypted version of her private key and then encrypts the whole thing. When Bob gets it, he can no longer know whether she flipped 0 or 1, and this does not involve randomization.

[lwanatt]

maybe you can explain it to me no matter how i imagine it i cant figure out how you could send a key with out compromising your security with the act of sending the key, unless you used a separate line that the government wouldnt be recording, like rf for example, the only way to make a truely secure connection is to deliver the initial key in person and send new keys regularly through the encrypted link

[lwanatt]

your right i need to develop a way of speaking to my friends in metaphor you could never be used in court because no one could prove what your words meant

[wresing]

If you want to keep your communications secure from government spying, simply rely on images and metaphor, especially ones involving compassion and empathy. Speak clearly with care and insight. It will all be gobbledygook to them.

[someman7]

You just said otherwise few hours ago. I'm saying, you don't need a quantum computer for quantum criptography which you implied... Wah.

[sonnyhe2002]

hmmm, i really have no idea what ur saying