Ruby

RSA Encrypt String to Encoded Result and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt a string to a base64 encoded result, and the reverse. Ruby

require 'chilkat'

success = false

# The RSA public key is used for encryption, and the private key for decryption.

# The public key's role is to make encryption accessible to anyone while ensuring that
# only the private key holder can decrypt the messages.
# The public key is designed to be widely distributed so anyone can use it to encrypt messages
# intended for the owner of the private key.

glob = Chilkat::CkGlobal.new()
glob.put_DefaultUtf8(true)

# Load our 2048-bit RSA public key.
pubKey = Chilkat::CkPublicKey.new()
# In all Chilkat methods expecting a path, you pass either absolute or relative paths.
success = pubKey.LoadFromFile("rsaKeys/myTestRsaPublic.pem")
if (success == false)
    print pubKey.lastErrorText() + "\n";
    exit
end

rsa = Chilkat::CkRsa.new()

# Tell RSA to use the public key.
rsa.UsePublicKey(pubKey)

# RSA encryption is for small amounts of data, on the order of 200 bytes or less.
# The maximum number of bytes that can be RSA encrypted depends
# on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
# For specific limits, see: RSA Encryption Maximum Number of Bytes

# Encrypt the utf-8 byte representation of the string.
rsa.put_Charset("utf-8")
rsa.put_EncodingMode("base64")

# Be Careful when Using non-us-ascii String Literals in Source Code
encryptedB64 = rsa.encryptStringENC("Élève français dîne à côté d’un café où l’on sert déjà du gâteau au chocolat et des éclairs délicieux",false)

# ------------------------------------------------------------------------------------------------------------------------
# Let's decrypt, which requires the matching private key...

# Load the matching 2048-bit RSA private key.
privKey = Chilkat::CkPrivateKey.new()
password = "secret"
success = privKey.LoadAnyFormatFile("rsaKeys/myTestRsaPrivate.pem",password)
if (success == false)
    print privKey.lastErrorText() + "\n";
    exit
end

# Tell the RSA object to use the private key.
rsa.UsePrivateKey(privKey)

# Indicate that after decrypting the resultant decrypted bytes contains the utf-8 byte representation of the text.
rsa.put_Charset("utf-8")
rsa.put_EncodingMode("base64")
originalText = rsa.decryptStringENC(encryptedB64,true)
if (success == false)
    print rsa.lastErrorText() + "\n";
    exit
end

print "Original text = " + originalText + "\n";
print "Success." + "\n";