import gnupg
import os
import sys

# Encrypt and decrypt using GPG public-key cryptography
# - 2048 bit RSA private key
# - 256 bit AES block cipher
# - standard and compatible
# - enables remote encryption
# - reliable, stood the test of time
# - not so fast, not so compact

def gen_key(key):
	home, uid, passphrase = key.split(' ')
	gpg = gnupg.GPG(gnupghome=home)
	input_data = gpg.gen_key_input(
		name_email=uid,
		passphrase=passphrase)
	fingerprint = gpg.gen_key(input_data)
	return fingerprint

def encrypt(text, key):
	home, uid, passphrase = key.split(' ')
	gpg = gnupg.GPG(gnupghome=home)
	result = gpg.encrypt(text, uid)
	if not result.ok:
		raise Exception("gpg.encrypt failed: "+result.status+" "+result.stderr)
	ciphertext = str(result)
	return ciphertext

def decrypt(ciphertext, key):
	home, uid, passphrase = key.split(' ')
	gpg = gnupg.GPG(gnupghome=home)
	result = gpg.decrypt(ciphertext, passphrase=passphrase)
	if not result.ok:
		raise Exception("gpg.decrypt failed: "+result.status+" "+result.stderr)
	text = result.data
	return text

def test(n=2):
	crypto = sys.modules[__name__]

	key = './gpghome test@aiki.info passphrase'

	home, uid, passphrase = key.split(' ')
	if not os.path.exists(home):
		fingerprint = crypto.gen_key(key)
		print "key fingerprint", fingerprint
	else:
		gpg = gnupg.GPG(gnupghome=home)
		pubkeys = gpg.list_keys()
		print "key fingerprints", pubkeys.fingerprints

	text = "hello \0 world, this is a little crypto test\0"
	print "text, len", repr(text), len(text)
	for i in range(0, int(n)):
		enc = crypto.encrypt(text, key)
		print "encrypted", enc
		dec = crypto.decrypt(enc, key)
		assert dec == text, "crypto.test"
		print "decrypted OK"

if __name__ == "__main__":
	op = sys.argv[1]
	print globals()[op](*sys.argv[2:])