20 lines
771 B
Plaintext
20 lines
771 B
Plaintext
import "../../utils/pack/u32/pack128" as pack128;
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import "../../utils/pack/u32/unpack128" as unpack128;
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import "./512bitPadded" as sha256;
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// A function that takes an array of 4 field elements as input, unpacks each of them to 128
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// bits (big endian), concatenates them and applies sha256.
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// It then returns an array of two field elements, each representing 128 bits of the result.
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def main(field[4] preimage) -> field[2] {
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u32[4] a_bits = unpack128(preimage[0]);
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u32[4] b_bits = unpack128(preimage[1]);
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u32[4] c_bits = unpack128(preimage[2]);
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u32[4] d_bits = unpack128(preimage[3]);
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u32[8] lhs = [...a_bits, ...b_bits];
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u32[8] rhs = [...c_bits, ...d_bits];
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u32[8] r = sha256(lhs, rhs);
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return [pack128(r[0..4]), pack128(r[4..8])];
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} |