You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
29 lines
879 B
Go
29 lines
879 B
Go
// Copyright (c) 2021 Tulir Asokan
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla Public
|
|
// License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
|
|
// Package hkdfutil contains a simple wrapper for golang.org/x/crypto/hkdf that reads a specified number of bytes.
|
|
package hkdfutil
|
|
|
|
import (
|
|
"crypto/sha256"
|
|
"fmt"
|
|
|
|
"golang.org/x/crypto/hkdf"
|
|
)
|
|
|
|
func SHA256(key, salt, info []byte, length uint8) []byte {
|
|
data := make([]byte, length)
|
|
h := hkdf.New(sha256.New, key, salt, info)
|
|
n, err := h.Read(data)
|
|
if err != nil {
|
|
// Length is limited to 255 by being uint8, so these errors can't actually happen
|
|
panic(fmt.Errorf("failed to expand key: %w", err))
|
|
} else if uint8(n) != length {
|
|
panic(fmt.Errorf("didn't read enough bytes (got %d, wanted %d)", n, length))
|
|
}
|
|
return data
|
|
}
|