ciphers/rsa.go
2022-07-30 18:30:44 +10:00

151 lines
3.1 KiB
Go

package ciphers
import (
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
"hash"
)
var (
ErrPubKeyNotCorrect = errors.New("rsa public key is not correct")
)
// GenerateKeyPair generates a new key pair
func GenerateKeyPair(bits int) (*rsa.PrivateKey, error) {
privkey, err := rsa.GenerateKey(rand.Reader, bits)
if err != nil {
return nil, err
}
return privkey, nil
}
// PrivateKeyToBytes private key to bytes
func PrivateKeyToBytes(priv *rsa.PrivateKey) []byte {
privBytes := pem.EncodeToMemory(
&pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: x509.MarshalPKCS1PrivateKey(priv),
},
)
return privBytes
}
// PublicKeyToBytes public key to bytes
func PublicKeyToBytes(pub *rsa.PrivateKey) ([]byte, error) {
pubASN1, err := x509.MarshalPKIXPublicKey(&pub.PublicKey)
if err != nil {
return nil, err
}
pubBytes := pem.EncodeToMemory(&pem.Block{
Type: "PUBLIC KEY",
Bytes: pubASN1,
})
return pubBytes, nil
}
func BytesRsaKeyToGo(priv, pub []byte) (*rsa.PrivateKey, error) {
key, err := BytesToPrivateKey(priv)
if err != nil {
return nil, err
}
pubKey, err := BytesToPublicKey(pub)
if err != nil {
return nil, err
}
key.PublicKey = rsa.PublicKey{
N: pubKey.N,
E: pubKey.E,
}
return key, nil
}
//
func BytesPublicKeyToGo(pub []byte) (*rsa.PublicKey, error) {
pubKey, err := BytesToPublicKey(pub)
if err != nil {
return nil, err
}
return &rsa.PublicKey{
N: pubKey.N,
E: pubKey.E,
}, nil
}
// BytesToPrivateKey bytes to private key
func BytesToPrivateKey(priv []byte) (*rsa.PrivateKey, error) {
block, _ := pem.Decode(priv)
enc := x509.IsEncryptedPEMBlock(block)
b := block.Bytes
var err error
if enc {
//log.Println("is encrypted pem block")
b, err = x509.DecryptPEMBlock(block, nil)
if err != nil {
return nil, err
}
}
key, err := x509.ParsePKCS1PrivateKey(b)
if err != nil {
return nil, err
}
return key, nil
}
// BytesToPublicKey bytes to public key
func BytesToPublicKey(pub []byte) (*rsa.PublicKey, error) {
block, _ := pem.Decode(pub)
enc := x509.IsEncryptedPEMBlock(block)
b := block.Bytes
var err error
if enc {
//log.Println("is encrypted pem block")
b, err = x509.DecryptPEMBlock(block, nil)
if err != nil {
return nil, err
}
}
ifc, err := x509.ParsePKIXPublicKey(b)
if err != nil {
return nil, err
}
key, ok := ifc.(*rsa.PublicKey)
if !ok {
return nil, ErrPubKeyNotCorrect
}
return key, nil
}
// EncryptWithPublicKey OAEP encrypts data with public key
func EncryptWithPublicKeyOAEP(hash hash.Hash, msg []byte, pub *rsa.PublicKey) ([]byte, error) {
//hash := sha512.New()
//hash := sha1.New()
ciphertext, err := rsa.EncryptOAEP(hash, rand.Reader, pub, msg, nil)
if err != nil {
return nil, err
}
return ciphertext, nil
}
// DecryptWithPrivateKey OAEP decrypts data with private key
func DecryptWithPrivateKeyOAEP(hash hash.Hash, ciphertext []byte, priv *rsa.PrivateKey) ([]byte, error) {
//hash := sha512.New()
//hash := sha1.New()
plaintext, err := rsa.DecryptOAEP(hash, rand.Reader, priv, ciphertext, nil)
if err != nil {
return nil, err
}
return plaintext, nil
}