Collision (Hashing)

Updated 31 Jul 2026

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def
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  when two different inputs produce the same hash digest
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significance
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  a hashing algorithm known to be capable of producing collisions is considered broken and should be deprecated/retired
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  risk example — malware could be inserted into a file such that the tampered file produces the same digest as the original, defeating integrity checks meant to detect tampering
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example
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  MD5 is known to be capable of generating collisions (known since roughly the mid-1990s), which is why more cryptographically secure algorithms like SHA-256 are preferred wherever security matters
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related
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cards
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  What is a hash collision, and why is it a serious problem?
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    When two different inputs produce the same hash digest; it breaks integrity verification (a tampered file could match the original's digest) and marks the algorithm as broken

Linked references 8