54 lines
1.3 KiB
Go
54 lines
1.3 KiB
Go
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/*
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Copyright 2015 Home Office All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package main
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import (
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"io"
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"crypto/rand"
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)
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var StdChars = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()-_=+,.?/:;{}[]`~")
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func NewPassword(length int) string {
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return rand_char(length, StdChars)
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}
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func rand_char(length int, chars []byte) string {
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new_pword := make([]byte, length)
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random_data := make([]byte, length+(length/4)) // storage for random bytes.
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clen := byte(len(chars))
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maxrb := byte(256 - (256 % len(chars)))
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i := 0
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for {
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if _, err := io.ReadFull(rand.Reader, random_data); err != nil {
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panic(err)
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}
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for _, c := range random_data {
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if c >= maxrb {
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continue
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}
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new_pword[i] = chars[c%clen]
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i++
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if i == length {
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return string(new_pword)
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}
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}
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}
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panic("unreachable")
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}
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