使用包uniuri，它生成加密安全的统一(无偏)字符串。

免责声明:我是该软件包的作者

使用包uniuri，它生成加密安全的统一(无偏)字符串。

免责声明:我是该软件包的作者

如果您想要加密安全的随机数，并且确切的字符集是灵活的(例如，base64就可以)，那么您可以根据所需的输出大小精确计算所需的随机字符的长度。

64进制文本比256进制文本长1/3。(2^8 vs 2^6;8位/6位= 1.333比率)

import (
    "crypto/rand"
    "encoding/base64"
    "math"
)

func randomBase64String(l int) string {
    buff := make([]byte, int(math.Ceil(float64(l)/float64(1.33333333333))))
    rand.Read(buff)
    str := base64.RawURLEncoding.EncodeToString(buff)
    return str[:l] // strip 1 extra character we get from odd length results
}

注意:你也可以使用RawStdEncoding，如果你喜欢+和/字符-和_

如果你想要十六进制，以16为底比以256为底长2倍。(2^8 vs 2^4;8位/4位= 2x比例)

import (
    "crypto/rand"
    "encoding/hex"
    "math"
)


func randomBase16String(l int) string {
    buff := make([]byte, int(math.Ceil(float64(l)/2)))
    rand.Read(buff)
    str := hex.EncodeToString(buff)
    return str[:l] // strip 1 extra character we get from odd length results
}

但是，如果您的字符集使用base256到baseN编码器，则可以将其扩展到任何任意字符集。你可以用同样的大小计算需要多少位来表示你的字符集。任何任意字符集的比率计算是:ratio = 8 / log2(len(字符集)))。

虽然这两种解决方案都是安全的，简单的，应该是快速的，并且不会浪费您的加密熵池。

这是一个游乐场，它适用于任何尺寸。https://play.golang.org/p/_yF_xxXer0Z

在icza精彩解释的解决方案之后，这里是它的一个修改，使用加密/兰特而不是数学/兰特。

const (
    letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" // 52 possibilities
    letterIdxBits = 6                    // 6 bits to represent 64 possibilities / indexes
    letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
)

func SecureRandomAlphaString(length int) string {

    result := make([]byte, length)
    bufferSize := int(float64(length)*1.3)
    for i, j, randomBytes := 0, 0, []byte{}; i < length; j++ {
        if j%bufferSize == 0 {
            randomBytes = SecureRandomBytes(bufferSize)
        }
        if idx := int(randomBytes[j%length] & letterIdxMask); idx < len(letterBytes) {
            result[i] = letterBytes[idx]
            i++
        }
    }

    return string(result)
}

// SecureRandomBytes returns the requested number of bytes using crypto/rand
func SecureRandomBytes(length int) []byte {
    var randomBytes = make([]byte, length)
    _, err := rand.Read(randomBytes)
    if err != nil {
        log.Fatal("Unable to generate random bytes")
    }
    return randomBytes
}

如果你想要一个更通用的解决方案，它允许你传入字符字节的切片来创建字符串，你可以尝试使用这个:

// SecureRandomString returns a string of the requested length,
// made from the byte characters provided (only ASCII allowed).
// Uses crypto/rand for security. Will panic if len(availableCharBytes) > 256.
func SecureRandomString(availableCharBytes string, length int) string {

    // Compute bitMask
    availableCharLength := len(availableCharBytes)
    if availableCharLength == 0 || availableCharLength > 256 {
        panic("availableCharBytes length must be greater than 0 and less than or equal to 256")
    }
    var bitLength byte
    var bitMask byte
    for bits := availableCharLength - 1; bits != 0; {
        bits = bits >> 1
        bitLength++
    }
    bitMask = 1<<bitLength - 1

    // Compute bufferSize
    bufferSize := length + length / 3

    // Create random string
    result := make([]byte, length)
    for i, j, randomBytes := 0, 0, []byte{}; i < length; j++ {
        if j%bufferSize == 0 {
            // Random byte buffer is empty, get a new one
            randomBytes = SecureRandomBytes(bufferSize)
        }
        // Mask bytes to get an index into the character slice
        if idx := int(randomBytes[j%length] & bitMask); idx < availableCharLength {
            result[i] = availableCharBytes[idx]
            i++
        }
    }

    return string(result)
}

如果你想传入你自己的随机源，修改上面的内容来接受io是很简单的。Reader而不是使用crypto/rand。

package main

import (
    "encoding/base64"
    "fmt"
    "math/rand"
    "time"
)

// customEncodeURL is like `bas64.encodeURL` 
// except its made up entirely of uppercase characters:
const customEncodeURL = "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKL"

// Random generates a random string.
// It is not cryptographically secure.
func Random(n int) string {
    b := make([]byte, n)
    rand.Seed(time.Now().UnixNano())
    _, _ = rand.Read(b) // docs say that it always returns a nil error.

    customEncoding := base64.NewEncoding(customEncodeURL).WithPadding(base64.NoPadding)
    return customEncoding.EncodeToString(b)
}

func main() {
    fmt.Println(Random(16))
}

作为icza的出色解决方案的后续，下面我使用rand。读者

func RandStringBytesMaskImprRandReaderUnsafe(length uint) (string, error) {
    const (
        charset     = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
        charIdxBits = 6                  // 6 bits to represent a letter index
        charIdxMask = 1<<charIdxBits - 1 // All 1-bits, as many as charIdxBits
        charIdxMax  = 63 / charIdxBits   // # of letter indices fitting in 63 bits
    )

    buffer := make([]byte, length)
    charsetLength := len(charset)
    max := big.NewInt(int64(1 << uint64(charsetLength)))

    limit, err := rand.Int(rand.Reader, max)
    if err != nil {
        return "", err
    }

    for index, cache, remain := int(length-1), limit.Int64(), charIdxMax; index >= 0; {
        if remain == 0 {
            limit, err = rand.Int(rand.Reader, max)
            if err != nil {
                return "", err
            }

            cache, remain = limit.Int64(), charIdxMax
        }

        if idx := int(cache & charIdxMask); idx < charsetLength {
            buffer[index] = charset[idx]
            index--
        }

        cache >>= charIdxBits
        remain--
    }

    return *(*string)(unsafe.Pointer(&buffer)), nil
}


func BenchmarkBytesMaskImprRandReaderUnsafe(b *testing.B) {
    b.ReportAllocs()
    b.ResetTimer()

    const length = 16

    b.RunParallel(func(pb *testing.PB) {
        for pb.Next() {
            RandStringBytesMaskImprRandReaderUnsafe(length)
        }
    })
}