cryptomedium

MACdonalds

hackerlab

Task: CBC-MAC implementation without proper finalization, need to forge two different messages with the same MAC. Solution: Length extension attack - create m2 = m1 || (m1 XOR MAC(m1)) which produces the same MAC as m1.

$ ls tags/ techniques/
xorblock_ciphercbc_maclength_extensionmac_forgerycollision_attackaes_ecbmessage_authentication
CBC-MAC length extension attackMAC collision/forgery via message extensionXOR manipulation of cipher blocks
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