forked from openprivacy/libricochet-go
84 lines
2.6 KiB
Go
84 lines
2.6 KiB
Go
package utils
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import (
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"crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"encoding/pem"
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"github.com/agl/ed25519/extra25519"
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"golang.org/x/crypto/curve25519"
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"golang.org/x/crypto/ed25519"
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"io/ioutil"
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"math"
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"math/big"
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)
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const (
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// InvalidPrivateKeyFileError is a library error, thrown when the given key file fials to load
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InvalidPrivateKeyFileError = Error("InvalidPrivateKeyFileError")
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// RicochetKeySize - tor onion services currently use rsa key sizes of 1024 bits
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RicochetKeySize = 1024
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)
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// GetRandNumber is a helper function which returns a random integer, this is
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// currently mostly used to generate messageids
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func GetRandNumber() *big.Int {
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num, err := rand.Int(rand.Reader, big.NewInt(math.MaxUint32))
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// If we can't generate random numbers then panicking is probably
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// the best option.
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CheckError(err)
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return num
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}
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// EDH implements diffie hellman using curve25519 keys derived from ed25519 keys
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// NOTE: This uses a 3rd party library extra25519 as the key conversion is not in the core golang lib
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// as such this definitely needs further review.
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func EDH(privateKey ed25519.PrivateKey, remotePublicKey ed25519.PublicKey) [32]byte {
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var privKeyBytes [64]byte
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var remotePubKeyBytes [32]byte
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copy(privKeyBytes[:], privateKey[:])
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copy(remotePubKeyBytes[:], remotePublicKey[:])
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var secret, curve25519priv, curve25519pub [32]byte
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extra25519.PrivateKeyToCurve25519(&curve25519priv, &privKeyBytes)
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extra25519.PublicKeyToCurve25519(&curve25519pub, &remotePubKeyBytes)
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curve25519.ScalarMult(&secret, &curve25519priv, &curve25519pub)
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return secret
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}
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// GeneratePrivateKeyV3 cryptographically creats a new ed25519 key pair.
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func GeneratePrivateKeyV3() (ed25519.PublicKey, ed25519.PrivateKey, error) {
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return ed25519.GenerateKey(rand.Reader)
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}
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// LoadPrivateKeyFromFile loads a private key from a file...
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func LoadPrivateKeyFromFile(filename string) (*rsa.PrivateKey, error) {
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pemData, err := ioutil.ReadFile(filename)
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if err != nil {
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return nil, err
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}
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return ParsePrivateKey(pemData)
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}
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// ParsePrivateKey Convert a private key string to a usable private key
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func ParsePrivateKey(pemData []byte) (*rsa.PrivateKey, error) {
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block, _ := pem.Decode(pemData)
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if block == nil || block.Type != "RSA PRIVATE KEY" {
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return nil, InvalidPrivateKeyFileError
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}
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return x509.ParsePKCS1PrivateKey(block.Bytes)
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}
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// PrivateKeyToString turns a private key into storable string
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func PrivateKeyToString(privateKey *rsa.PrivateKey) string {
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privateKeyBlock := pem.Block{
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Type: "RSA PRIVATE KEY",
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Headers: nil,
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Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
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}
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return string(pem.EncodeToMemory(&privateKeyBlock))
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}
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