Go: get public/private key from id_rsa PEM file

rsa.go

import (
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"

	"github.com/Northern-Lights/going/file"
)

// LoadPrivate loads an (unencrypted) RSA private key from PEM data
func LoadPrivate(filepath string) (*rsa.PrivateKey, error) {
  // Read the bytes of the PEM file, e.g. id_rsa
	pemData, e := file.Read(filepath)
	if e != nil {
		return nil, e
	}
  
  // Use the PEM decoder and parse the private key
	pemBlock, _ := pem.Decode(pemData)
	priv, e := x509.ParsePKCS1PrivateKey(pemBlock.Bytes)
  
  // Public key can be obtained through priv.PublicKey
	return priv, e
}