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Forked from miguelmota/rsa_util.go
Created December 2, 2021 10:53
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Golang RSA encrypt and decrypt example
package ciphers
import (
"crypto/rand"
"crypto/rsa"
"crypto/sha512"
"crypto/x509"
"encoding/pem"
"log"
)
// GenerateKeyPair generates a new key pair
func GenerateKeyPair(bits int) (*rsa.PrivateKey, *rsa.PublicKey) {
privkey, err := rsa.GenerateKey(rand.Reader, bits)
if err != nil {
log.Error(err)
}
return privkey, &privkey.PublicKey
}
// 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.PublicKey) []byte {
pubASN1, err := x509.MarshalPKIXPublicKey(pub)
if err != nil {
log.Error(err)
}
pubBytes := pem.EncodeToMemory(&pem.Block{
Type: "RSA PUBLIC KEY",
Bytes: pubASN1,
})
return pubBytes
}
// BytesToPrivateKey bytes to private key
func BytesToPrivateKey(priv []byte) *rsa.PrivateKey {
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 {
log.Error(err)
}
}
key, err := x509.ParsePKCS1PrivateKey(b)
if err != nil {
log.Error(err)
}
return key
}
// BytesToPublicKey bytes to public key
func BytesToPublicKey(pub []byte) *rsa.PublicKey {
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 {
log.Error(err)
}
}
ifc, err := x509.ParsePKIXPublicKey(b)
if err != nil {
log.Error(err)
}
key, ok := ifc.(*rsa.PublicKey)
if !ok {
log.Error("not ok")
}
return key
}
// EncryptWithPublicKey encrypts data with public key
func EncryptWithPublicKey(msg []byte, pub *rsa.PublicKey) []byte {
hash := sha512.New()
ciphertext, err := rsa.EncryptOAEP(hash, rand.Reader, pub, msg, nil)
if err != nil {
log.Error(err)
}
return ciphertext
}
// DecryptWithPrivateKey decrypts data with private key
func DecryptWithPrivateKey(ciphertext []byte, priv *rsa.PrivateKey) []byte {
hash := sha512.New()
plaintext, err := rsa.DecryptOAEP(hash, rand.Reader, priv, ciphertext, nil)
if err != nil {
log.Error(err)
}
return plaintext
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