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The doc formatting changes introduced in the recent go version is increasing the diff for all of the new commits. Formatting it all in this commit will help the readability of future PRs by reducing the diff.
46 lines
2.1 KiB
Go
46 lines
2.1 KiB
Go
// Copyright (c) 2013-2021 The btcsuite developers
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// Copyright (c) 2015-2021 The Decred developers
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package btcec
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import (
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secp "github.com/decred/dcrd/dcrec/secp256k1/v4"
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)
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// ModNScalar implements optimized 256-bit constant-time fixed-precision
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// arithmetic over the secp256k1 group order. This means all arithmetic is
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// performed modulo:
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//
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// 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141
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//
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// It only implements the arithmetic needed for elliptic curve operations,
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// however, the operations that are not implemented can typically be worked
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// around if absolutely needed. For example, subtraction can be performed by
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// adding the negation.
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//
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// Should it be absolutely necessary, conversion to the standard library
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// math/big.Int can be accomplished by using the Bytes method, slicing the
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// resulting fixed-size array, and feeding it to big.Int.SetBytes. However,
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// that should typically be avoided when possible as conversion to big.Ints
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// requires allocations, is not constant time, and is slower when working modulo
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// the group order.
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type ModNScalar = secp.ModNScalar
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// NonceRFC6979 generates a nonce deterministically according to RFC 6979 using
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// HMAC-SHA256 for the hashing function. It takes a 32-byte hash as an input
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// and returns a 32-byte nonce to be used for deterministic signing. The extra
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// and version arguments are optional, but allow additional data to be added to
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// the input of the HMAC. When provided, the extra data must be 32-bytes and
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// version must be 16 bytes or they will be ignored.
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//
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// Finally, the extraIterations parameter provides a method to produce a stream
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// of deterministic nonces to ensure the signing code is able to produce a nonce
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// that results in a valid signature in the extremely unlikely event the
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// original nonce produced results in an invalid signature (e.g. R == 0).
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// Signing code should start with 0 and increment it if necessary.
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func NonceRFC6979(privKey []byte, hash []byte, extra []byte, version []byte,
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extraIterations uint32) *ModNScalar {
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return secp.NonceRFC6979(privKey, hash, extra, version, extraIterations)
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}
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