edraw2pem

#!/usr/bin/python3

import argparse
import base64
import binascii
import sys

from cryptography.hazmat.primitives.asymmetric import ed448, ed25519
from cryptography.hazmat.primitives.serialization import (
    Encoding,
    NoEncryption,
    PrivateFormat,
    PublicFormat,
)

ap = argparse.ArgumentParser()
ap.add_argument("key", help="raw key (default: base64, Ed25519 public key)")
ap.add_argument("-x", "--hex", action="store_true", help="hex input instead of base64")
ap.add_argument("--ed25519priv", action="store_true", help="Ed448 private key")
ap.add_argument("--ed448pub", action="store_true", help="Ed448 public key")
ap.add_argument("--ed448priv", action="store_true", help="Ed448 private key")
args = ap.parse_args()

if args.ed448priv or args.ed448pub:
    LEN = 57
else:
    LEN = 32

if args.hex:
    binx = binascii.unhexlify(args.key)
else:
    binx = base64.b64decode(args.key)
if len(binx) != LEN:
    print(f"{len(binx)}b wrong length ({LEN}b expected)")
    sys.exit(1)

if args.ed448priv:
    key = ed448.Ed448PrivateKey.from_private_bytes(binx)
    pem = key.private_bytes(Encoding.PEM, PrivateFormat.PKCS8, NoEncryption())
elif args.ed448pub:
    key = ed448.Ed448PublicKey.from_public_bytes(binx)
    pem = key.public_bytes(Encoding.PEM, PublicFormat.SubjectPublicKeyInfo)
elif args.ed25519priv:
    key = ed25519.Ed25519PrivateKey.from_private_bytes(binx)
    pem = key.private_bytes(Encoding.PEM, PrivateFormat.PKCS8, NoEncryption())
else:
    key = ed25519.Ed25519PublicKey.from_public_bytes(binx)
    pem = key.public_bytes(Encoding.PEM, PublicFormat.SubjectPublicKeyInfo)

print(pem.decode(), end="")