CODEWITHSUNDEEP
rubystringencryptioncastingrsa
Adjam
Adjam

Reputation: 640

Ruby, how to convert a string to an RSA public key

I need to use RSA encryption to encode a message. I store the private and public keys in two separate text files, but I can only get as far as encoding a message. I need a way to cast a string into an RSA key, so that I can decode the message.

My code so far:

require 'openssl'
require 'base64'


if File.exist?("./pub_key.txt")

  #Keys are strings, I can encrypt but not decrypt a message
  pri = File.read("./pri_key.txt")
  pub = File.read("./pub_key.txt")

  puts pub

  string = 'Hello World!';

  rsa_public_key = OpenSSL::PKey::RSA.new(pub)
  encrypted_string = Base64.encode64(rsa_public_key.public_encrypt(string))

  puts encrypted_string 

  # This throws an error
  # Because 'pri' is a string, don't know how to cast it to the right type
  #my_string = pri.private_decrypt(Base64.decode64(encrypted_string))

  puts "The decoded message"
  #puts my_string


end

Upvotes: 0

Views: 4060

Answers (1)

Adjam
Adjam

Reputation: 640

I fixed the code

Turns out I just needed this line:

rsa_private_key = OpenSSL::PKey::RSA.new(pri)

The full working code

require 'openssl'
require 'base64'


if File.exist?("./pub_key.txt")

  #Keys are strings, I can encrypt but not decrypt a message
  pri = File.read("./pri_key.txt")
  pub = File.read("./pub_key.txt")

  puts pub

  string = 'Hello World!';

  rsa_public_key = OpenSSL::PKey::RSA.new(pub)
  rsa_private_key = OpenSSL::PKey::RSA.new(pri)
  encrypted_string = Base64.encode64(rsa_public_key.public_encrypt(string))

  puts encrypted_string 

  # This throws an error
  # Because 'pri' is a string, don't know how to cast it to the right type
  my_string = rsa_private_key .private_decrypt(Base64.decode64(encrypted_string))

  puts "The decoded message"
  puts my_string


end

Thanks for your time! Rubber duck programming works :)

Upvotes: 2

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