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rand.go
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rand.go
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// Copyright 2018 ETH Zurich, Anapaya Systems
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package scrypto
import (
"crypto/rand"
"encoding/binary"
mrand "math/rand"
"github.com/scionproto/scion/pkg/private/common"
)
const (
ErrInvalidNonceSize common.ErrMsg = "Invalid nonce size"
ErrUnableToGenerateNonce common.ErrMsg = "Unable to generate nonce"
)
func init() {
// Seed math/rand's default generator with a random value, once.
mrand.Seed(RandInt64())
}
func RandUint64() uint64 {
b := make([]byte, 8)
if _, err := rand.Read(b); err != nil {
// If this happens, there's some serious problem with the runtime or
// OS, and there's nothing we can do about it.
panic("No random numbers available")
}
return binary.LittleEndian.Uint64(b)
}
// RandInt64 returns a random int64 value. The returned value can be negative.
func RandInt64() int64 {
return int64(RandUint64())
}