Cryptography and Security

Claudio Orlandi

@CSDay2013

Group Members

2 Professors 4 PostDocs

12 PhD Students

Centers

Courses

• Bachelor

– Distributed Systems Q3

– Security Q4

• Master

– Cryptography Q1+Q2

– Quantum Information Processing Q1+Q2

– Cryptologic Protocol Theory Q3+Q4

Courses

• Bachelor

– Distributed Systems Q3

– Security Q4

• Master

– Cryptography Q1+Q2

– Quantum Information Processing Q1+Q2

– Cryptologic Protocol Theory Q3+Q4

• NEW Master Course!

– Cryptographic Computing Q1+Q2

Cryptography

• In the beginning...

• In the beginning...

Cryptography

Cryptography

• Encryption for Confidentiality

• Digital Signatures for Authenticity

Cryptography

• With Cryptography

so what now?

Interactive Computation

x y

f(x,y) f(x,y)

Interactive Computation

x y

f(x,y) f(x,y)

Secure Computation

x y

f(x,y) f(x,y)

for example...

Secure Computation

x y

f(x,y) f(x,y)

Cryptographic Computation

x y

Cryptographic Computation

Enc(x) y x

Cryptographic Computation

Enc(x) y x

Cryptographic Computation

Enc(x)

nc(x*y)

X Y X*Y

0 0 0

0 1 0

1 0 0

1 1 1

y x

Enc(x*y)

Cryptographic Computation

x*y

Enc(x)

Enc(x*y) X Y X*Y

0 0 0

0 1 0

1 0 0

1 1 1

y x

Under the hood

• Complexity

– Computational hardness, one-way functions, reductions...

• Number theory

– Prime numbers, factoring, elliptic curves, lattices, ...

• Physical assumptions

– Quantum cryptography, noisy channels...

• ...

Other examples...

…and more

• Secure Outsourcing

• Verifiable Computation

• Electronic Voting

• Electronic Cash

• …

…and more

• Secure Outsourcing

• Verifiable Computation

• Electronic Voting

• Electronic Cash

• …

Thanks!