(Ruby) JWE using "dir" Direct use of Shared Symmetric Key

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

Note: This example requires Chilkat v9.5.0.66 or greater.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# This requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# Note: This example requires Chilkat v9.5.0.66 or greater.

plaintext = "Live long and prosper."

jwe = Chilkat::CkJwe.new()

# First build the JWE Protected Header..
jweProtHdr = Chilkat::CkJsonObject.new()
jweProtHdr.AppendString("alg","dir")
jweProtHdr.AppendString("enc","A128GCM")

# Don't forget to actually provide the protected header to the JWE object:
jwe.SetProtectedHeader(jweProtHdr)

# The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
# Given that the "alg" = "dir", we are to directly specify the AES GCM key.
# (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

# Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

# The SetWrappingKey method is also used for "dir" direct keys.
# However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
# which is specified by calling SetWrappingKey with an index of 0.

recipientIndex = 0
jwe.SetWrappingKey(recipientIndex,"000102030405060708090A0B0C0D0E0F","hex")

# Encrypt and return the JWE:
strJwe = jwe.encrypt(plaintext,"utf-8")
if (jwe.get_LastMethodSuccess() != true)
    print jwe.lastErrorText() + "\n";
    exit
end

# Show the JWE we just created:
print strJwe + "\n";

# Decrypt the JWE.
jwe2 = Chilkat::CkJwe.new()
success = jwe2.LoadJwe(strJwe)
if (success != true)
    print jwe2.lastErrorText() + "\n";
    exit
end

jwe2.SetWrappingKey(0,"000102030405060708090A0B0C0D0E0F","hex")

# Decrypt.
originalPlaintext = jwe2.decrypt(0,"utf-8")
if (jwe2.get_LastMethodSuccess() != true)
    print jwe2.lastErrorText() + "\n";
    exit
end

print "original text: " + "\n";
print originalPlaintext + "\n";

# Sample output:
# eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
# original text: 
# Live long and prosper.