dns/dnssec_privkey.go

78 lines
2.3 KiB
Go

package dns
import (
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"math/big"
"strconv"
)
const format = "Private-key-format: v1.3\n"
var bigIntOne = big.NewInt(1)
// PrivateKeyString converts a PrivateKey to a string. This string has the same
// format as the private-key-file of BIND9 (Private-key-format: v1.3).
// It needs some info from the key (the algorithm), so its a method of the DNSKEY.
// It supports *rsa.PrivateKey, *ecdsa.PrivateKey and ed25519.PrivateKey.
func (r *DNSKEY) PrivateKeyString(p crypto.PrivateKey) string {
algorithm := strconv.Itoa(int(r.Algorithm))
algorithm += " (" + AlgorithmToString[r.Algorithm] + ")"
switch p := p.(type) {
case *rsa.PrivateKey:
modulus := toBase64(p.PublicKey.N.Bytes())
e := big.NewInt(int64(p.PublicKey.E))
publicExponent := toBase64(e.Bytes())
privateExponent := toBase64(p.D.Bytes())
prime1 := toBase64(p.Primes[0].Bytes())
prime2 := toBase64(p.Primes[1].Bytes())
// Calculate Exponent1/2 and Coefficient as per: http://en.wikipedia.org/wiki/RSA#Using_the_Chinese_remainder_algorithm
// and from: http://code.google.com/p/go/issues/detail?id=987
p1 := new(big.Int).Sub(p.Primes[0], bigIntOne)
q1 := new(big.Int).Sub(p.Primes[1], bigIntOne)
exp1 := new(big.Int).Mod(p.D, p1)
exp2 := new(big.Int).Mod(p.D, q1)
coeff := new(big.Int).ModInverse(p.Primes[1], p.Primes[0])
exponent1 := toBase64(exp1.Bytes())
exponent2 := toBase64(exp2.Bytes())
coefficient := toBase64(coeff.Bytes())
return format +
"Algorithm: " + algorithm + "\n" +
"Modulus: " + modulus + "\n" +
"PublicExponent: " + publicExponent + "\n" +
"PrivateExponent: " + privateExponent + "\n" +
"Prime1: " + prime1 + "\n" +
"Prime2: " + prime2 + "\n" +
"Exponent1: " + exponent1 + "\n" +
"Exponent2: " + exponent2 + "\n" +
"Coefficient: " + coefficient + "\n"
case *ecdsa.PrivateKey:
var intlen int
switch r.Algorithm {
case ECDSAP256SHA256:
intlen = 32
case ECDSAP384SHA384:
intlen = 48
}
private := toBase64(intToBytes(p.D, intlen))
return format +
"Algorithm: " + algorithm + "\n" +
"PrivateKey: " + private + "\n"
case ed25519.PrivateKey:
private := toBase64(p.Seed())
return format +
"Algorithm: " + algorithm + "\n" +
"PrivateKey: " + private + "\n"
default:
return ""
}
}