I have a problem with authentication using multiple public keys. I used example from gliderlabs/ssh github but it is only using first public key in the file and discard every other.
func ExamplePublicKeyAuth() {
ssh.ListenAndServe(":2222", nil,
ssh.PublicKeyAuth(func(ctx ssh.Context, key ssh.PublicKey) bool {
data, _ := ioutil.ReadFile(path.Join(os.Getenv("HOME"), ".ssh/authorized_keys"))
allowed, _, _, _, _ := ssh.ParseAuthorizedKey(data)
return ssh.KeysEqual(key, allowed)
}),
)
}
Does anyone know how to make it work with multiple public keys?
Related
How does one verify that a public key matched private key?
On start of the application, 2048-bit RSA keys are loaded from base64 PEM encoded string. I wish to verify that the keys are valid and that they match before continuing. The signing and verification is done by the underlining library I'm using.
I could sign and verify dummy data, but I am looking for alternative solutions.
Starter playground: https://play.golang.org/p/tsB8Yp-xs47
The solution is pretty simple
func verifyKeyPair(private, public string) bool {
// Handle errors here
block, _ := pem.Decode([]byte(rsaPrivateKey))
key, _ := x509.ParsePKCS1PrivateKey(block.Bytes)
pubBlock, _ := pem.Decode([]byte(rsaPublicKey))
pubKey, _ := x509.ParsePKIXPublicKey(pubBlock.Bytes)
return key.PublicKey.Equal(pubKey)
}
https://play.golang.org/p/tR6Ns0wDrlN
or alternatively if you want to handle other supported algorithms :
// KeysMatch generic check if public key is the same.
func KeysMatch(priv crypto.PrivateKey, pub crypto.PublicKey) bool {
privkey, ok := priv.(interface {
Public() crypto.PublicKey
})
if !ok {
return false
}
pubkey, ok := privkey.Public().(interface {
Equal(crypto.PublicKey) bool
})
if !ok {
return false
}
return pubkey.Equal(pub)
}
I see private key, but where to provide the public key so I can publish. Works perfectly but I am missing the public key, where is it given while creating the JWT token? I assume the example key (dnfksdmfksd) below is the private key. I am using github.com/dgrijalva/jwt-go Thanks!
func CreateToken(userid uint64) (string, error) {
var err error
//Creating Access Token
os.Setenv("ACCESS_SECRET", "jdnfksdmfksd") //this should be in an env file
atClaims := jwt.MapClaims{}
atClaims["authorized"] = true
atClaims["user_id"] = userid
atClaims["exp"] = time.Now().Add(time.Minute * 15).Unix()
at := jwt.NewWithClaims(jwt.SigningMethodHS256, atClaims)
token, err := at.SignedString([]byte(os.Getenv("ACCESS_SECRET")))
if err != nil {
return "", err
}
return token, nil
}
HS256 is a symmetric algorithm. It uses a shared secret. There is not public/private key. The recipients of the JWT have to use the same secret to validate the signature.
I need to encrypt client-private-key with RSA-2048 server-public-key.
I know that private key is obviously longer than the public key and I'm not sure if it's possible... but I saw a similar task was done in Python, so I want to know your opinion.
/* main */
clientPrivateKey, _ := generateRsaPair(2048)
_, serverPublicKey := generateRsaPair(2048)
clientPrivateKeyAsByte := privateKeyToBytes(clientPrivateKey)
encryptWithPublicKey(clientPrivateKeyAsByte, serverPublicKey)
Fatal error crypto/rsa: message too long for RSA public key size
/* Functions */
func generateRsaPair(bits int) (*rsa.PrivateKey, *rsa.PublicKey) {
privkey, err := rsa.GenerateKey(rand.Reader, bits)
if err != nil {
log.Error(err)
}
return privkey, &privkey.PublicKey
}
func encryptWithPublicKey(msg []byte, pub *rsa.PublicKey) []byte {
hash := sha512.New()
ciphertext, err := rsa.EncryptOAEP(hash, rand.Reader, pub, msg, nil)
checkError(err)
return ciphertext
}
func privateKeyToBytes(priv *rsa.PrivateKey) []byte {
privBytes := pem.EncodeToMemory(
&pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: x509.MarshalPKCS1PrivateKey(priv),
},
)
return privBytes
}
If you want to encrypt something larger than the key size then you can simply use hybrid encryption. You first encrypt (or wrap, if a specific wrapping operation is available) the encoding of the private key using a random AES key, e.g. using AES-CBC or AES-CTR (with an all zero IV). Then you encrypt that AES key using the private key. The ciphertext consists of the encrypted AES key followed by the encrypted data - in this case an RSA private key.
Note however that a private key should really be managed by one entity. It is not called a private key for nothing. Distributing private keys is generally considered bad key management practice.
I am working on a go project that will need to verify an OpenPGP public key, to be able to use it to verify file signatures.
I've generated a root key, and another key, which I've signed with the root key (let's call the second key signed). I've exported the public part of the signed key to an armored text file, for easy distribution:
gpg --export -a signed > signed.asc
I've written this go code which illustrates what I want to do, in the end:
package main
import (
"flag"
"fmt"
"golang.org/x/crypto/openpgp"
"os"
)
func main() {
var keyringpath string
var signedkeypath string
flag.StringVar(&keyringpath, "keyring", "", "keyring")
flag.StringVar(&signedkeypath, "signedkey", "", "signed key")
flag.Parse()
// read the keyring
keyring, err := os.Open(keyringpath)
if err != nil {
panic(err)
}
el, err := openpgp.ReadKeyRing(keyring)
if err != nil {
panic(err)
}
var rootidentity *openpgp.Entity
for _, entity := range el {
if _, ok := entity.Identities["root"]; ok {
rootidentity = entity
}
}
fmt.Printf("%+v\n", rootidentity)
// read the public armored key
signedkey, err := os.Open(signedkeypath)
if err != nil {
panic(err)
}
el, err = openpgp.ReadArmoredKeyRing(signedkey)
if err != nil {
panic(err)
}
signed := el[0]
fmt.Printf("%+v\n", signed)
// there is only one signature on signed, the one produced by root
signature := signed.Identities["signed"].Signatures[0]
err = rootidentity.PrimaryKey.VerifyKeySignature(signed.PrimaryKey, signature)
if err != nil {
panic(err)
}
}
When I run it, I give keyring my public keyring (~/.gnupg/pubring.gpg) and signedkey my exported signed key (signed.asc).
In production, the idea is to also export the root public key from pubring.gpg into armored text, and embed that in the code.
The signature fails to verify with the following error:
panic: openpgp: invalid signature: hash tag doesn't match
Looking at the code of VerifyKeySignature (and especially this comment), I get the feeling that it's meant to only be used to verify signatures on subkeys, rather than other keys.
So, the question is, given two public PGP keys, one signed by the other, how do I verify that signature using the openpgp library?
Not sure whether I should close this question or not: I found the answer. It isn't very clear in the docs, but VerifyKeySignature is indeed probably only used for subkeys. For verifying the signatures on other users' public keys, use VerifyUserIdSignature, like so:
err = rootidentity.PrimaryKey.VerifyUserIdSignature("signed", signed.PrimaryKey, signature)
if err != nil {
panic(err)
}
I want to sign a public key from ascii armor with a private key in go language.For that I developed following code but the problem is when I check the signature in gpg --check-sigs the signature created by code is shown as "bad Signature".Please Help as I cant figure out any way of solving it.I have already postd on golang-nuts.I am just learning golang for my college project and I am stuck here,Please help.
// signer
package main
import (
"bytes"
"code.google.com/p/go.crypto/openpgp"
"code.google.com/p/go.crypto/openpgp/armor"
"code.google.com/p/go.crypto/openpgp/packet"
"fmt"
)
// This function takes asciiarmored private key which will sign the public key
//Public key is also ascii armored,pripwd is password of private key in string
//This function will return ascii armored signed public key i.e. (pubkey+sign by prikey)
func SignPubKeyPKS(asciiPub string, asciiPri string, pripwd string) (asciiSignedKey string) {
//get Private key from armor
_, priEnt := getPri(asciiPri, pripwd) //pripwd is the password todecrypt the private key
_, pubEnt := getPub(asciiPub) //This will generate signature and add it to pubEnt
usrIdstring := ""
for _, uIds := range pubEnt.Identities {
usrIdstring = uIds.Name
}
fmt.Println(usrIdstring)
errSign := pubEnt.SignIdentity(usrIdstring, &priEnt, nil)
if errSign != nil {
fmt.Println("Signing Key ", errSign.Error())
return
}
asciiSignedKey = PubEntToAsciiArmor(pubEnt)
return
}
//get packet.PublicKey and openpgp.Entity of Public Key from ascii armor
func getPub(asciiPub string) (pubKey packet.PublicKey, retEntity openpgp.Entity) {
read1 := bytes.NewReader([]byte(asciiPub))
entityList, errReadArm := openpgp.ReadArmoredKeyRing(read1)
if errReadArm != nil {
fmt.Println("Reading Pubkey ", errReadArm.Error())
return
}
for _, pubKeyEntity := range entityList {
if pubKeyEntity.PrimaryKey != nil {
pubKey = *pubKeyEntity.PrimaryKey
retEntity = *pubKeyEntity
}
}
return
}
//get packet.PrivateKEy and openpgp.Entity of Private Key from ascii armor
func getPri(asciiPri string, pripwd string) (priKey packet.PrivateKey, priEnt openpgp.Entity) {
read1 := bytes.NewReader([]byte(asciiPri))
entityList, errReadArm := openpgp.ReadArmoredKeyRing(read1)
if errReadArm != nil {
fmt.Println("Reading PriKey ", errReadArm.Error())
return
}
for _, can_pri := range entityList {
smPr := can_pri.PrivateKey
retEntity := can_pri
if smPr == nil {
fmt.Println("No Private Key")
return
}
priKey = *smPr
errDecr := priKey.Decrypt([]byte(pripwd))
if errDecr != nil {
fmt.Println("Decrypting ", errDecr.Error())
return
}
retEntity.PrivateKey = &priKey
priEnt = *retEntity
}
return
}
//Create ASscii Armor from openpgp.Entity
func PubEntToAsciiArmor(pubEnt openpgp.Entity) (asciiEntity string) {
gotWriter := bytes.NewBuffer(nil)
wr, errEncode := armor.Encode(gotWriter, openpgp.PublicKeyType, nil)
if errEncode != nil {
fmt.Println("Encoding Armor ", errEncode.Error())
return
}
errSerial := pubEnt.Serialize(wr)
if errSerial != nil {
fmt.Println("Serializing PubKey ", errSerial.Error())
}
errClosing := wr.Close()
if errClosing != nil {
fmt.Println("Closing writer ", errClosing.Error())
}
asciiEntity = gotWriter.String()
return
}
The code looks roughly ok, except that it really should be stricter with error checking. Panicking on error is better then no error checking at all (because it will usually segfault sometimes later).
The problem is that the implementation of Signature.SignUserId() inside code.google.com/p/go.crypto/openpgp is wrong. It is using the algorithm that signs a key (which is use to certify that the subkey belongs to the primary key) instead of the algorithm that signs a user id.
In addition, while exploring this I realized that PublicKey.VerifyUserIdSignature() is implemented in such a way that it only works for self-signed user ids, because it doesn't use the right public key in the hash.
Bug report, with patch https://code.google.com/p/go/issues/detail?id=7371