github.com/emmansun/gmsm@v0.29.1/internal/sm2ec/fiat/sm2p256scalar.go (about)

     1  // Copyright 2021 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Code generated by generate.go. DO NOT EDIT.
     6  
     7  package fiat
     8  
     9  import (
    10  	"crypto/subtle"
    11  	"errors"
    12  )
    13  
    14  // SM2P256OrderElement is an integer modulo 2^256 - 2^224 - 188730267045675049073202170516080344797.
    15  //
    16  // The zero value is a valid zero element.
    17  type SM2P256OrderElement struct {
    18  	// Values are represented internally always in the Montgomery domain, and
    19  	// converted in Bytes and SetBytes.
    20  	x sm2p256scalarMontgomeryDomainFieldElement
    21  }
    22  
    23  const sm2p256scalarElementLen = 32
    24  
    25  type sm2p256scalarUntypedFieldElement = [4]uint64
    26  
    27  // One sets e = 1, and returns e.
    28  func (e *SM2P256OrderElement) One() *SM2P256OrderElement {
    29  	sm2p256scalarSetOne(&e.x)
    30  	return e
    31  }
    32  
    33  // Equal returns 1 if e == t, and zero otherwise.
    34  func (e *SM2P256OrderElement) Equal(t *SM2P256OrderElement) int {
    35  	eBytes := e.Bytes()
    36  	tBytes := t.Bytes()
    37  	return subtle.ConstantTimeCompare(eBytes, tBytes)
    38  }
    39  
    40  // IsZero returns 1 if e == 0, and zero otherwise.
    41  func (e *SM2P256OrderElement) IsZero() int {
    42  	zero := make([]byte, sm2p256scalarElementLen)
    43  	eBytes := e.Bytes()
    44  	return subtle.ConstantTimeCompare(eBytes, zero)
    45  }
    46  
    47  // Set sets e = t, and returns e.
    48  func (e *SM2P256OrderElement) Set(t *SM2P256OrderElement) *SM2P256OrderElement {
    49  	e.x = t.x
    50  	return e
    51  }
    52  
    53  // Bytes returns the 32-byte big-endian encoding of e.
    54  func (e *SM2P256OrderElement) Bytes() []byte {
    55  	// This function is outlined to make the allocations inline in the caller
    56  	// rather than happen on the heap.
    57  	var out [sm2p256scalarElementLen]byte
    58  	return e.bytes(&out)
    59  }
    60  
    61  func (e *SM2P256OrderElement) bytes(out *[sm2p256scalarElementLen]byte) []byte {
    62  	var tmp sm2p256scalarNonMontgomeryDomainFieldElement
    63  	sm2p256scalarFromMontgomery(&tmp, &e.x)
    64  	sm2p256scalarToBytes(out, (*sm2p256scalarUntypedFieldElement)(&tmp))
    65  	sm2p256scalarInvertEndianness(out[:])
    66  	return out[:]
    67  }
    68  
    69  // SetBytes sets e = v, where v is a big-endian 32-byte encoding, and returns e.
    70  // If v is not 32 bytes or it encodes a value higher than 2^256 - 2^224 - 188730267045675049073202170516080344797,
    71  // SetBytes returns nil and an error, and e is unchanged.
    72  func (e *SM2P256OrderElement) SetBytes(v []byte) (*SM2P256OrderElement, error) {
    73  	if len(v) != sm2p256scalarElementLen {
    74  		return nil, errors.New("invalid SM2P256OrderElement encoding")
    75  	}
    76  	/*
    77  	// Check for non-canonical encodings (p + k, 2p + k, etc.) by comparing to
    78  	// the encoding of -1 mod p, so p - 1, the highest canonical encoding.
    79  	var minusOneEncoding = new(SM2P256OrderElement).Sub(
    80  		new(SM2P256OrderElement), new(SM2P256OrderElement).One()).Bytes()
    81  	for i := range v {
    82  		if v[i] < minusOneEncoding[i] {
    83  			break
    84  		}
    85  		if v[i] > minusOneEncoding[i] {
    86  			return nil, errors.New("invalid SM2P256OrderElement encoding")
    87  		}
    88  	}*/
    89  	var in [sm2p256scalarElementLen]byte
    90  	copy(in[:], v)
    91  	sm2p256scalarInvertEndianness(in[:])
    92  	var tmp sm2p256scalarNonMontgomeryDomainFieldElement
    93  	sm2p256scalarFromBytes((*sm2p256scalarUntypedFieldElement)(&tmp), &in)
    94  	sm2p256scalarToMontgomery(&e.x, &tmp)
    95  	return e, nil
    96  }
    97  
    98  // Add sets e = t1 + t2, and returns e.
    99  func (e *SM2P256OrderElement) Add(t1, t2 *SM2P256OrderElement) *SM2P256OrderElement {
   100  	sm2p256scalarAdd(&e.x, &t1.x, &t2.x)
   101  	return e
   102  }
   103  
   104  // Sub sets e = t1 - t2, and returns e.
   105  func (e *SM2P256OrderElement) Sub(t1, t2 *SM2P256OrderElement) *SM2P256OrderElement {
   106  	sm2p256scalarSub(&e.x, &t1.x, &t2.x)
   107  	return e
   108  }
   109  
   110  // Mul sets e = t1 * t2, and returns e.
   111  func (e *SM2P256OrderElement) Mul(t1, t2 *SM2P256OrderElement) *SM2P256OrderElement {
   112  	sm2p256scalarMul(&e.x, &t1.x, &t2.x)
   113  	return e
   114  }
   115  
   116  // Square sets e = t * t, and returns e.
   117  func (e *SM2P256OrderElement) Square(t *SM2P256OrderElement) *SM2P256OrderElement {
   118  	sm2p256scalarSquare(&e.x, &t.x)
   119  	return e
   120  }
   121  
   122  // Select sets v to a if cond == 1, and to b if cond == 0.
   123  func (v *SM2P256OrderElement) Select(a, b *SM2P256OrderElement, cond int) *SM2P256OrderElement {
   124  	sm2p256scalarSelectznz((*sm2p256scalarUntypedFieldElement)(&v.x), sm2p256scalarUint1(cond),
   125  		(*sm2p256scalarUntypedFieldElement)(&b.x), (*sm2p256scalarUntypedFieldElement)(&a.x))
   126  	return v
   127  }
   128  
   129  func sm2p256scalarInvertEndianness(v []byte) {
   130  	for i := 0; i < len(v)/2; i++ {
   131  		v[i], v[len(v)-1-i] = v[len(v)-1-i], v[i]
   132  	}
   133  }