Your IP: Unknown · Your Status: ProtectedUnprotectedUnknown

Skip to main content

Birthday attack

Birthday attack

Birthday attack definition

A birthday attack is an attack that occurs when someone exploits the mathematics behind the birthday problem in probability theory to launch a cryptographic attack. The birthday problem states that in a group of 23 people, there’s a 50% chance that at least two will have the same birthday. This probability increases rapidly as the group size gets bigger. For instance, in a group of 50 people, the likelihood is already over 97%.

During a birthday attack, the attacker tries to find two different input messages that produce the same hash value, called a collision. By finding a collision, the attacker can deceive a system into believing that two other notes are identical. For instance, they can forge a digital signature or crack a password hash.

Birthday attacks pose a significant security threat because they are relatively easy to execute and can undermine various cryptographic systems.

See also: hybrid attack, hash function

Protecting against birthday attacks

  • Use robust cryptographic algorithms and implement them correctly.
  • Employ strong encryption.
  • Regularly update hash functions.
  • Use salted hashes.
  • Implement message authentication codes (MACs).
  • Practice rigorous key management.
  • Maintain vigilant system monitoring.
  • Conduct regular security audits.
  • Promote security awareness and training.

Further reading

Ultimate digital security