Full Key Recovery attack on HMAC MD4

Gaëtan Leurent

Description

Full Key-Recovery attack on HMAC-MD4 G. Leurent Introduction MD4 HMAC and NMAC Previous work Wang's attack NMAC attack New ideas IV-dependent paths Message pairs Differential paths Extracting more Conclusion Full Key-Recovery Attacks on HMAC/NMAC-MD4 and NMAC-MD5 Pierre-Alain Fouque, Gaëtan Leurent, Phong Nguyen Laboratoire d'Informatique de l'École Normale Supérieure CRYPTO 2007 1/ 26

• laboratoire d'informatique de l'ecole normale


• introduction md4


• bob ?


• nmac attack


• bob share


• full key-recovery

Sujets

• Fouqué

Informations

• Publié par: pefav
• Nombre de lectures: 21
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Full Key-Recovery attack on HMAC-MD4

G. Leurent

Introduction MD4

HMAC and NMAC

Previous work Wang’s attack

NMAC attack

New ideas IV-dependent paths Message pairs Differential paths Extracting more

Conclusion

1 / 26

Full Key-Rec HMAC/NMAC-

overy MD4 a

Attacks on nd NMAC-MD5

Pierre-Alain Fouque,Gaëtan

Leurent, Phong

Nguyen

Laboratoire d’Informatique de l’École Normale Supérieure

CRYPTO

2007

Full Key-Recovery attack on HMAC-MD4

G. Leurent

Introduction MD4

HMAC and NMAC

Previous work Wang’s attack NMAC attack

New ideas IV-dependent paths Message pairs Differential paths Extracting more

Conclusion

2 / 26

What

◮

◮

◮

◮

◮

is

a

MAC

algorithm?

M

Alice wants to send a message to Bob

But Charlie has access to the communication

Alice and Bob share a secret key

...and use a

MAC algorithm.

Bob rejects the message if

k...

MAC k (M)6=

t

channel

Full Key-Recovery attack on HMAC-MD4

G. Leurent

Introduction MD4

HMAC and NMAC

Previous work Wang’s attack NMAC attack

New ideas IV-dependent paths Message pairs Differential paths Extracting more

Conclusion

2 / 26

What

◮

◮

◮

◮

◮

is

a

MAC

algorithm?

M

Alice wants to send a message to Bob

But Charlie has access to the communication

Alice and Bob share a secret key

...and use a

MAC algorithm.

Bob rejects the message if

k...

MAC k (M)6=

t

channel

Full Key-Recovery attack on HMAC-MD4

G. Leurent

Introduction MD4 HMAC and NMAC

Previous work

Wang’s attack NMAC attack

New ideas IV-dependent paths Message pairs Differential paths Extracting more

Conclusion

2 / 26

What

◮

◮

◮

◮

◮

is

a

MAC

k

algorithm?

M

Alice wants to send a message

to

Bob

k

But Charlie has access to the communication

Alice and Bob share a secret key

...and use a MAC algorithm.

k...

Bob rejects the message if MAC k (M)6=

t

channel

Full Key-Recovery attack on HMAC-MD4

G. Leurent

Introduction MD4 HMAC and NMAC

Previous work Wang’s attack NMAC attack

New ideas IV-dependent paths Message pairs Differential paths Extracting more

Conclusion

2 / 26

What

◮

◮

◮

◮

◮

t

is

=

a

MAC

k

MAC k (M

Alice wants to

algorithm?

send

a

Mt

message to

Bob

k

But Charlie has access to the communication Alice and Bob share a secret keyk...

...and use a MAC algorithm.

Bob rejects the

message if MAC k (M)6=

t

channel