#!/usr/bin/env python

"""
openssl genrsa -out example.com.rsa 1280
dnssec-keyfromrsa example.com.rsa >Kexample.com.+008+33333.private
"""

from subprocess import Popen,PIPE
import sys,StringIO,re,base64

# only these make sense with RSA keys
dnssecalg={
  '1':'RSAMD5',
  '5':'RSASHA1',
  '8':'RSASHA256',
  '10':'RSASHA512',
}

tag=33333
alg=8
file=sys.argv[1]

rsafile = open(file,'r')

rsaparser=Popen(["openssl","rsa","-text"],stdin=rsafile,stdout=PIPE)
(output,outerr)=rsaparser.communicate()

# parse openssl RSA output into dict
rsadict={}
rsaitem=None
for l in StringIO.StringIO(output):
  l = l.strip('\n\r')
  if l[0:5] == '-----':
    break

  m = re.match('^([A-Za-z0-9-]+):\s*(.*?)\s*$',l)
  if m:
    rsaitem=m.group(1).lower()
    rsaline=m.group(2)
    rsadict[rsaitem]=rsaline
    continue

  l = l.strip(' ')
  if rsaitem:
    rsadict[rsaitem] = rsadict[rsaitem]+l

# show the dict in the desired format
for k in ['Private-key-format','Algorithm','Modulus',
    'PublicExponent','PrivateExponent','Prime1','Prime2',
    'Exponent1','Exponent2','Coefficient']:
  if k == 'Private-key-format':
    v = 'v1.2'
  elif k == 'Algorithm':
    v = '%s (%s)'%(alg,dnssecalg[str(alg)])
  elif k == 'PublicExponent':
    v = 'AQAB'
  else:
    vhex=rsadict[k.lower()]
    v = base64.b64encode(re.sub('[:]','',vhex).decode('hex'))
    #print '<%s/%s>'%(vhex,v)

  print '%s: %s'%(k,v)