Go 中的 OpenPGP 错误：“加密：请求的哈希函数不可用”

Question

我正在玩Go的openpgp包，方法是制作一个简单的程序来加密一条短消息并用 ASCII 码来保护它。我目前拥有的代码是：

package main

import (

    "code.google.com/p/go.crypto/openpgp"

    "code.google.com/p/go.crypto/openpgp/armor"

    "fmt"

    "log"

    "os"

)

func main() {

    to, err := openpgp.NewEntity("John Smith", "comment", "[e-mail]", nil)

    if err != nil {

        log.Fatal(err)

    }

    from, err := openpgp.NewEntity("John Smith", "comment", "[e-mail]", nil)

    if err != nil {

        log.Fatal(err)

    }

    recipients := []*openpgp.Entity{to}

    armorer, err := armor.Encode(os.Stdout, "PGP MESSAGE", nil)

    if err != nil {

        log.Fatal(err)

    }

    defer armorer.Close()

    encrypter, err := openpgp.Encrypt(armorer, recipients, from, nil, nil)

    if err != nil {

        log.Fatal(err)

    }

    defer encrypter.Close()

    fmt.Fprintf(encrypter, "Hello! How are you?")

}

当我运行它时，我得到输出：

-----BEGIN PGP MESSAGE-----

wcBMA5iJWayscZQHAQgAvHQtyGxzyHJNYQlK7bcYZnWRm1gHsRRVZIgPTxtqnklp

KgCYOuv5dtgqUXinJWZnk3DozR7xbMj/c9oSlifJ9FiPnTaLLOIVhv2Jf7w9ydh3

oig3vpL8rI/ha9bOJsNdznt3/z1ZLVghPsrRGHO7LWUTWQUn/cgQZXr/z5CpGQP0

TFlMcbBuuwE2ffplAGkBSQlXNRx1ZsY6T+MjajWwcik/CjJ/NnzRpURpXFIWc85x

HQbUexQzEghyh4t5NEQhx9UvmLtnKPmwnhxX3s43Zcd1VtzSXc77giE08fSdIDdH

eDClMno6jsoWhmubXZVXOHqf+z5euEcxvYyk16N/jdLgAeMBTSifCFR8YuGBmOFA

DONO/4/M1ye76+KyhsbF4KTgK+CW4Rjg4NLi0ubP1A==

=YD2p

-----END PGP MESSAGE-----panic: crypto: requested hash function is unavailable

goroutine 1 [running]:

crypto.Hash.New(0x9, 0x21027c4b0, 0x1d3300)

        /usr/local/Cellar/go/1.1.1/src/pkg/crypto/crypto.go:62 +0xab

code.google.com/p/go.crypto/openpgp.Encrypt(0x210299e70, 0x2102e76e0, 0x2210284f38, 0x1, 0x1, ...)

        /Users/cb/workspace/go/src/code.google.com/p/go.crypto/openpgp/write.go:289 +0x1141

main.main()

        /Users/cb/workspace/go/src/github.com/xoebus/gpg/go-gpg.go:31 +0x425

exit status 2

看起来它正在输出装甲密文（似乎无效）然后崩溃，因为它找不到链接到二进制文件的注册哈希函数。据我所知，默认情况下它应该使用标准库中的一个 SHA 哈希值，这绝对应该被链接？

我究竟做错了什么？

Answer 1

散列函数必须由import _ "whatever". 不会自动链接到您的二进制文件中。实际上，没有明确（或可传递地）导入的内容。但是，如果您直接使用一些非导入的实体，编译器/链接器会抱怨。散列函数 OTOH 以及 stdlib 的其他一些部分通过散列接口使用一种后期绑定。(09:25) jnml@fsc-r550:~/src/tmp/SO/17986762$ cat main.go package mainimport (        "fmt"        "log"        "os"        "code.google.com/p/go.crypto/openpgp"        "code.google.com/p/go.crypto/openpgp/armor"        _ "code.google.com/p/go.crypto/ripemd160")func main() {        to, err := openpgp.NewEntity("John Smith", "comment", "[e-mail]", nil)        if err != nil {                log.Fatal(err)        }        from, err := openpgp.NewEntity("John Smith", "comment", "[e-mail]", nil)        if err != nil {                log.Fatal(err)        }        recipients := []*openpgp.Entity{to}        armorer, err := armor.Encode(os.Stdout, "PGP MESSAGE", nil)        if err != nil {                log.Fatal(err)        }        defer armorer.Close()        encrypter, err := openpgp.Encrypt(armorer, recipients, from, nil, nil)        if err != nil {                log.Fatal(err)        }        defer encrypter.Close()        fmt.Fprintf(encrypter, "Hello! How are you?")}(09:25) jnml@fsc-r550:~/src/tmp/SO/17986762$ go run main.go -----BEGIN PGP MESSAGE-----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wWmw-----END PGP MESSAGE-----(09:26) jnml@fsc-r550:~/src/tmp/SO/17986762$