(Ruby) JWE with DEFLATE Compression

Demonstrates how to DEFLATE ("zip") compress the JWE payload prior to encryption.

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.

# Create some plaintext to be encrypted.
# This example will demonstrate with and without DEFLATE (zip) compression.
sbPlainText = Chilkat::CkStringBuilder.new()
bCrLf = true
line = "Live long and prosper."
sbPlainText.AppendLine(line,bCrLf)
sbPlainText.AppendLine(line,bCrLf)
sbPlainText.AppendLine(line,bCrLf)
sbPlainText.AppendLine(line,bCrLf)

# The text to be encrypted:
print sbPlainText.getAsString() + "\n";

jwe = Chilkat::CkJwe.new()

# Build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256","zip":"DEF"}
# The "zip":"DEF" parameter indicates that the plaintext payload should
# be compressed prior to encryption.
jweProtHdr = Chilkat::CkJsonObject.new()
jweProtHdr.AppendString("alg","A128KW")
jweProtHdr.AppendString("enc","A128CBC-HS256")
jweProtHdr.AppendString("zip","DEF")
jwe.SetProtectedHeader(jweProtHdr)

# Set the AES key wrap key:
aesWrappingKey = "GawgguFyGrWKav7AX4VKUg"
jwe.SetWrappingKey(0,aesWrappingKey,"base64url")

# Encrypt and return the JWE in sbJweCompressed:
sbJweCompressed = Chilkat::CkStringBuilder.new()
success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweCompressed)
if (success != true)
    print jwe.lastErrorText() + "\n";
    exit
end

# Show the compressed JWE:
print sbJweCompressed.getAsString() + "\n";
print "size of compressed JWE: " + sbJweCompressed.get_Length().to_s() + "\n";

# Now create a JWE without compression.
jweProtHdr.Delete("zip")
# Make sure to update the shared protected header:
jwe.SetProtectedHeader(jweProtHdr)

sbJweUncompressed = Chilkat::CkStringBuilder.new()
success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweUncompressed)
if (success != true)
    print jwe.lastErrorText() + "\n";
    exit
end

# Show the uncompressed JWE:
print sbJweUncompressed.getAsString() + "\n";
print "size of uncompressed JWE: " + sbJweUncompressed.get_Length().to_s() + "\n";

# Decrypting is the same whether compression is used or not.
# The "zip" header in the JWE indicates that the payload should be 
# automatically decompressed (inflated) after decrypting.
jwe2 = Chilkat::CkJwe.new()
success = jwe2.LoadJweSb(sbJweCompressed)
if (success != true)
    print jwe2.lastErrorText() + "\n";
    exit
end

# Set the AES wrap key.
jwe2.SetWrappingKey(0,aesWrappingKey,"base64url")

# Decrypt (also automatically decompresses).
sbOriginalText = Chilkat::CkStringBuilder.new()
success = jwe2.DecryptSb(0,"utf-8",sbOriginalText)
if (success != true)
    print jwe2.lastErrorText() + "\n";
    exit
end

print "original text from compressed JWE: " + "\n";
print sbOriginalText.getAsString() + "\n";

# -----------------------------------------------------------
# Do the same with the uncompressed JWE

success = jwe2.LoadJweSb(sbJweUncompressed)
if (success != true)
    print jwe2.lastErrorText() + "\n";
    exit
end

# Set the AES wrap key.
jwe2.SetWrappingKey(0,aesWrappingKey,"base64url")

# Decrypt.
sbOriginalText.Clear()
success = jwe2.DecryptSb(0,"utf-8",sbOriginalText)
if (success != true)
    print jwe2.lastErrorText() + "\n";
    exit
end

print "original text from uncompressed JWE: " + "\n";
print sbOriginalText.getAsString() + "\n";

# ------------------------------------------------
# The output of this example is:
# (Note: Your output data will be different because the content encryption key is randomly generated.)

# eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiemlwIjoiREVGIn0.xuW-pEAIdEUFnk10m8ocursvktO8Of9ByCCAt6LgKkkOtCWCUn1kQw.zpGj-9WVni3cQxyOuZbcGA.0hzP1myua3oYpUHwCIY_3edBUREbUpLaX6wYuJduOdI.Ppc6aEO3y3B8BJ1FKMPjlA
# size of compressed JWE: 212
# eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.N4KeyC7nnSFkieJOyE24_zKeuV_m7v5UKoJb1TgV4Yc_r2RzUPNvyA.6AEdyXSCKx-iMmUJyypSLg.QpixfyrwhGpmwUDp623viik4smPav7vwPLiC2r-V-jwnSfEH3mxWu6DbrIz3mixaqATwynmEBzVPxvS9jTXpSAGCnniib4_0WoPl3r_wF5tlsKOEe--jpNso-DKd1Tp8jJxj3JkFWt3IRnUUKGj17g.sBfDwFc5fzpaI-UW8-SW4g
# size of uncompressed JWE: 303
# original text from compressed JWE: 
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
# 
# original text from uncompressed JWE: 
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
#