Rationale behind 256-bit words in EVM

Question

What were the design factors driving having EVM native words as 256-bit? It feels excessive, especially if one needs to process as large data set as blockchain.

score 18 · Accepted Answer · answered Jul 23 '16 at 22:06

18

Quote from Ethereum Design Rationale:

32 byte word size - the alternative is 4 or 8 byte words, as in most other architectures, or unlimited, as in Bitcoin. 4 or 8 byte words are too restrictive to store addresses and big values for crypto computations, and unlimited values are too hard to make a secure gas model around. 32 bytes is ideal because it is just large enough to store 32 byte values common in many crypto implementations, as well as addresses (and provides the ability to pack address and value into a single storage index as an optimization), but not so large as to be extremely inefficient.

answered Jul 23 '16 at 22:06

Fedor T.

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why cannot 16 byte word ? thanks. – hqt May 10 '18 at 20:42
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@hqt t specifies in many crypto implementations. By crypto, the author meant actual cryptography implementations. – Paul Razvan Berg Oct 16 '18 at 19:51

Rationale behind 256-bit words in EVM

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