mirror of
https://github.com/letic/terraform-provider-google.git
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961c878e0d
Switch to using Go modules. This migrates our vendor.json to use Go 1.11's modules system, and replaces the vendor folder with the output of go mod vendor. The vendored code should remain basically the same; I believe some tree shaking of packages and support scripts/licenses/READMEs/etc. happened. This also fixes Travis and our Makefile to no longer use govendor.
125 lines
3.3 KiB
Go
125 lines
3.3 KiB
Go
package curve25519
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import (
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"crypto/elliptic"
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"math/big"
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"sync"
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)
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var cv25519 cv25519Curve
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type cv25519Curve struct {
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*elliptic.CurveParams
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}
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func copyReverse(dst []byte, src []byte) {
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// Curve 25519 multiplication functions expect scalars in reverse
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// order than PGP. To keep the curve25519Curve type consistent
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// with other curves, we reverse it here.
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for i, j := 0, len(src)-1; j >= 0 && i < len(dst); i, j = i+1, j-1 {
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dst[i] = src[j]
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}
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}
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func copyTruncate(dst []byte, src []byte) {
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lenDst, lenSrc := len(dst), len(src)
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if lenDst == lenSrc {
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copy(dst, src)
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} else if lenDst > lenSrc {
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copy(dst[lenDst-lenSrc:lenDst], src)
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} else if lenDst < lenSrc {
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copy(dst, src[:lenDst])
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}
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}
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func (cv25519Curve) ScalarMult(x1, y1 *big.Int, scalar []byte) (x, y *big.Int) {
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// Assume y1 is 0 with cv25519.
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var dst [32]byte
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var x1Bytes [32]byte
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var scalarBytes [32]byte
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copyTruncate(x1Bytes[:], x1.Bytes())
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copyReverse(scalarBytes[:], scalar)
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scalarMult(&dst, &scalarBytes, &x1Bytes)
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x = new(big.Int).SetBytes(dst[:])
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y = new(big.Int)
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return x, y
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}
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func (cv25519Curve) ScalarBaseMult(scalar []byte) (x, y *big.Int) {
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var dst [32]byte
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var scalarBytes [32]byte
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copyReverse(scalarBytes[:], scalar[:32])
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scalarMult(&dst, &scalarBytes, &basePoint)
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x = new(big.Int).SetBytes(dst[:])
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y = new(big.Int)
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return x, y
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}
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func (cv25519Curve) IsOnCurve(bigX, bigY *big.Int) bool {
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return bigY.Sign() == 0 // bigY == 0 ?
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}
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// More information about 0x40 point format:
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// https://tools.ietf.org/html/draft-koch-eddsa-for-openpgp-00#section-3
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// In addition to uncompressed point format described here:
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// https://tools.ietf.org/html/rfc6637#section-6
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func (cv25519Curve) MarshalType40(x, y *big.Int) []byte {
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byteLen := 32
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ret := make([]byte, 1+byteLen)
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ret[0] = 0x40
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xBytes := x.Bytes()
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copyTruncate(ret[1:], xBytes)
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return ret
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}
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func (cv25519Curve) UnmarshalType40(data []byte) (x, y *big.Int) {
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if len(data) != 1+32 {
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return nil, nil
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}
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if data[0] != 0x40 {
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return nil, nil
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}
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x = new(big.Int).SetBytes(data[1:])
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// Any x is a valid curve point.
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return x, new(big.Int)
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}
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// ToCurve25519 casts given elliptic.Curve type to Curve25519 type, or
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// returns nil, false if cast was unsuccessful.
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func ToCurve25519(cv elliptic.Curve) (cv25519Curve, bool) {
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cv2, ok := cv.(cv25519Curve)
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return cv2, ok
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}
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func initCv25519() {
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cv25519.CurveParams = &elliptic.CurveParams{Name: "Curve 25519"}
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// Some code relies on these parameters being available for
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// checking Curve coordinate length. They should not be used
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// directly for any calculations.
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cv25519.P, _ = new(big.Int).SetString("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed", 16)
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cv25519.N, _ = new(big.Int).SetString("1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed", 16)
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cv25519.Gx, _ = new(big.Int).SetString("9", 16)
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cv25519.Gy, _ = new(big.Int).SetString("20ae19a1b8a086b4e01edd2c7748d14c923d4d7e6d7c61b229e9c5a27eced3d9", 16)
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cv25519.BitSize = 256
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}
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var initonce sync.Once
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// Cv25519 returns a Curve which (partially) implements Cv25519. Only
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// ScalarMult and ScalarBaseMult are valid for this curve. Add and
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// Double should not be used.
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func Cv25519() elliptic.Curve {
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initonce.Do(initCv25519)
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return cv25519
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}
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func (curve cv25519Curve) Params() *elliptic.CurveParams {
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return curve.CurveParams
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}
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