4d9c43593d
This introduce a new internal package to deal with the explicit clearing of data (such as private keys) in byte slices, byte arrays (32 and 64-bytes long), and multi-precision "big" integers. Benchmarks from a xeon e3 (Xor is the zeroing funcion which Bytes replaces): BenchmarkXor32 30000000 52.1 ns/op BenchmarkXor64 20000000 91.5 ns/op BenchmarkRange32 50000000 31.8 ns/op BenchmarkRange64 30000000 49.5 ns/op BenchmarkBytes32 200000000 10.1 ns/op BenchmarkBytes64 100000000 15.4 ns/op BenchmarkBytea32 1000000000 2.24 ns/op BenchmarkBytea64 300000000 4.46 ns/op Removes an XXX from the votingpool package.
49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
// Package zero contains functions to clear data from byte slices and
|
|
// multi-precision integers.
|
|
package zero
|
|
|
|
import (
|
|
"math/big"
|
|
)
|
|
|
|
// Bytes sets all bytes in the passed slice to zero. This is used to
|
|
// explicitly clear private key material from memory.
|
|
//
|
|
// In general, prefer to use the fixed-sized zeroing functions (Bytea*)
|
|
// when zeroing bytes as they are much more efficient than the variable
|
|
// sized zeroing func Bytes.
|
|
func Bytes(b []byte) {
|
|
z := [32]byte{}
|
|
n := uint(copy(b, z[:]))
|
|
for n < uint(len(b)) {
|
|
copy(b[n:], b[:n])
|
|
n <<= 1
|
|
}
|
|
}
|
|
|
|
// Bytea32 clears the 32-byte array by filling it with the zero value.
|
|
// This is used to explicitly clear private key material from memory.
|
|
func Bytea32(b *[32]byte) {
|
|
*b = [32]byte{}
|
|
}
|
|
|
|
// Bytea64 clears the 64-byte array by filling it with the zero value.
|
|
// This is used to explicitly clear sensitive material from memory.
|
|
func Bytea64(b *[64]byte) {
|
|
*b = [64]byte{}
|
|
}
|
|
|
|
// BigInt sets all bytes in the passed big int to zero and then sets the
|
|
// value to 0. This differs from simply setting the value in that it
|
|
// specifically clears the underlying bytes whereas simply setting the value
|
|
// does not. This is mostly useful to forcefully clear private keys.
|
|
func BigInt(x *big.Int) {
|
|
b := x.Bits()
|
|
z := [16]big.Word{}
|
|
n := uint(copy(b, z[:]))
|
|
for n < uint(len(b)) {
|
|
copy(b[n:], b[:n])
|
|
n <<= 1
|
|
}
|
|
x.SetInt64(0)
|
|
}
|