(PowerShell) JWE using RSAES-OAEP and AES GCM

This example duplicates the example A.1 in RFC 7516 for JSON Web Encryption (JWE).

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

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# 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 = "The true sign of intelligence is not knowledge but imagination."

# ---------------------------------
# A.1.1 JOSE Header
# First build the JWE Protected Header.
# We want to build this: {"alg":"RSA-OAEP","enc":"A256GCM"}
$jweProtHdr = New-Object Chilkat.JsonObject
$jweProtHdr.AppendString("alg","RSA-OAEP")
$jweProtHdr.AppendString("enc","A256GCM")
$("JWE Protected Header: " + $jweProtHdr.Emit())
$("--")

# ---------------------------------
# A.1.2 Content Encryption Key
# Note: Chilkat automatically generates the random CEK internally.
# The application does not need to explicitly take this step.

# ---------------------------------
# A.1.3.  Key Encryption
# The application should load an RSA private key from any format.
# However, the application does not need to explicitly construct the JWE Encrypted Key.
# Chilkat automatically does it internally.
# The design of the Chilkat JWE API is to allow the application to create the JWE
# after specifying the inputs.  (This is in contrast to forcing the application developer
# to painstakingly go through each step of the JWE construction process.)

# The specific RSA key used in the A.1 example is the following JWK:
$sbJwk = New-Object Chilkat.StringBuilder
$sbJwk.Append("{`"kty`": `"RSA`",")
$sbJwk.Append("`"n`": `"oahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E-BVvxkeDNjbC4he8rUW")
$sbJwk.Append("cJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3S")
$sbJwk.Append("psk_ZkoFnilakGygTwpZ3uesH-PFABNIUYpOiN15dsQRkgr0vEhxN92i2a")
$sbJwk.Append("sbOenSZeyaxziK72UwxrrKoExv6kc5twXTq4h-QChLOln0_mtUZwfsRaMS")
$sbJwk.Append("tPs6mS6XrgxnxbWhojf663tuEQueGC-FCMfra36C9knDFGzKsNa7LZK2dj")
$sbJwk.Append("YgyD3JR_MB_4NUJW_TqOQtwHYbxevoJArm-L5StowjzGy-_bq6Gw`",")
$sbJwk.Append("`"e`": `"AQAB`",")
$sbJwk.Append("`"d`": `"kLdtIj6GbDks_ApCSTYQtelcNttlKiOyPzMrXHeI-yk1F7-kpDxY4-WY5N")
$sbJwk.Append("WV5KntaEeXS1j82E375xxhWMHXyvjYecPT9fpwR_M9gV8n9Hrh2anTpTD9")
$sbJwk.Append("3Dt62ypW3yDsJzBnTnrYu1iwWRgBKrEYY46qAZIrA2xAwnm2X7uGR1hghk")
$sbJwk.Append("qDp0Vqj3kbSCz1XyfCs6_LehBwtxHIyh8Ripy40p24moOAbgxVw3rxT_vl")
$sbJwk.Append("t3UVe4WO3JkJOzlpUf-KTVI2Ptgm-dARxTEtE-id-4OJr0h-K-VFs3VSnd")
$sbJwk.Append("VTIznSxfyrj8ILL6MG_Uv8YAu7VILSB3lOW085-4qE3DzgrTjgyQ`",")
$sbJwk.Append("`"p`": `"1r52Xk46c-LsfB5P442p7atdPUrxQSy4mti_tZI3Mgf2EuFVbUoDBvaRQ-")
$sbJwk.Append("SWxkbkmoEzL7JXroSBjSrK3YIQgYdMgyAEPTPjXv_hI2_1eTSPVZfzL0lf")
$sbJwk.Append("fNn03IXqWF5MDFuoUYE0hzb2vhrlN_rKrbfDIwUbTrjjgieRbwC6Cl0`",")
$sbJwk.Append("`"q`": `"wLb35x7hmQWZsWJmB_vle87ihgZ19S8lBEROLIsZG4ayZVe9Hi9gDVCOBm")
$sbJwk.Append("UDdaDYVTSNx_8Fyw1YYa9XGrGnDew00J28cRUoeBB_jKI1oma0Orv1T9aX")
$sbJwk.Append("IWxKwd4gvxFImOWr3QRL9KEBRzk2RatUBnmDZJTIAfwTs0g68UZHvtc`",")
$sbJwk.Append("`"dp`": `"ZK-YwE7diUh0qR1tR7w8WHtolDx3MZ_OTowiFvgfeQ3SiresXjm9gZ5KL")
$sbJwk.Append("hMXvo-uz-KUJWDxS5pFQ_M0evdo1dKiRTjVw_x4NyqyXPM5nULPkcpU827")
$sbJwk.Append("rnpZzAJKpdhWAgqrXGKAECQH0Xt4taznjnd_zVpAmZZq60WPMBMfKcuE`",")
$sbJwk.Append("`"dq`": `"Dq0gfgJ1DdFGXiLvQEZnuKEN0UUmsJBxkjydc3j4ZYdBiMRAy86x0vHCj")
$sbJwk.Append("ywcMlYYg4yoC4YZa9hNVcsjqA3FeiL19rk8g6Qn29Tt0cj8qqyFpz9vNDB")
$sbJwk.Append("UfCAiJVeESOjJDZPYHdHY8v1b-o-Z2X5tvLx-TCekf7oxyeKDUqKWjis`",")
$sbJwk.Append("`"qi`": `"VIMpMYbPf47dT1w_zDUXfPimsSegnMOA1zTaX7aGk_8urY6R8-ZW1FxU7")
$sbJwk.Append("AlWAyLWybqq6t16VFd7hQd0y6flUK4SlOydB61gwanOsXGOAOv82cHq0E3")
$sbJwk.Append("eL4HrtZkUuKvnPrMnsUUFlfUdybVzxyjz9JF_XyaY14ardLSjf4L_FNY`"}")

# Load this JWK into a Chilkat private key object.
$rsaPrivKey = New-Object Chilkat.PrivateKey
$success = $rsaPrivKey.LoadJwk($sbJwk.GetAsString())
if ($success -ne $true) {
    $($rsaPrivKey.LastErrorText)
    exit
}

# The public key is used to encrypt (i.e. create the JWE), 
# and the private key is used to decrypt.
# The RSA public key is simply a subset of the private key.  The RSA public key
# is composed of the "n" and "e" members shown above.  These are also known as the
# modulus and exponent.
# We can simply get the public key object from the private key object
$rsaPubKey = $rsaPrivKey.GetPublicKey()

# ---------------------------------
# A.1.4.  Initialization Vector
# Chilkat automatically generates the necessary random IV internally.  
# The application does not need to do this explicitly.

# ---------------------------------
# A.1.5.  Additional Authenticated Data
# The Additional Authenticated Data encryption parameter is
# ASCII(BASE64URL(UTF8(JWE Protected Header))).
# Again, Chilkat automatically takes care of this internally.
# The application does not need to explicitly take this step.

# ---------------------------------
# A.1.6.  Content Encryption
# Again... this step is handled by Chilkat internally.

# ---------------------------------
# A.1.7.  Complete Representation
# The application need only call the Encrypt, EncryptSb, or EncryptBd method
# return the fully assembled JWE.  
# The final representation in the Compact Serialization 
# is the string BASE64URL(UTF8(JWE Protected Header)) || '.' ||
# BASE64URL(JWE Encrypted Key) || '.' || BASE64URL(JWE Initialization
# Vector) || '.' || BASE64URL(JWE Ciphertext) || '.' || BASE64URL(JWE
# Authentication Tag).

$jwe = New-Object Chilkat.Jwe
$jwe.SetProtectedHeader($jweProtHdr)
$jwe.SetPublicKey(0,$rsaPubKey)

$strJwe = $jwe.Encrypt($plaintext,"utf-8")
if ($jwe.LastMethodSuccess -ne $true) {
    $($jwe.LastErrorText)
    exit
}

# Note: The RSA OAEP algorithm uses random padding bytes internally.
# Therefore, the results will appear different each time -- even if the
# identical plaintext is encrypted with the identical RSA key. 
# (Do not expect the appearance of the results to be the same as what
# is published in the RFC.  However, what is published in the RFC *should*
# be decryptable using the code that follows.)
$($strJwe)

# Let's decrypt the JWE that was just produced.
# Do the following to decrypt a JWE:
# 1) Load the JWE.
# 2) Set the private key for decryption.
# 3) Decrypt.
$jwe2 = New-Object Chilkat.Jwe
$success = $jwe2.LoadJwe($strJwe)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

# Provide the RSA private key for decryption.
# (The JWE was encrypted for a single recipient at index 0.)
$jwe2.SetPrivateKey(0,$rsaPrivKey)

# Decrypt.
$originalPlaintext = $jwe2.Decrypt(0,"utf-8")
if ($jwe2.LastMethodSuccess -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$("original text: ")
$($originalPlaintext)

# ---------------------------------------------------------------------------------
# It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.1.7
# because it was produced using the same RSA key.

$sbJwe = New-Object Chilkat.StringBuilder
$sbJwe.Append("eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ.")
$sbJwe.Append("OKOawDo13gRp2ojaHV7LFpZcgV7T6DVZKTyKOMTYUmKoTCVJRgckCL9kiMT03JGe")
$sbJwe.Append("ipsEdY3mx_etLbbWSrFr05kLzcSr4qKAq7YN7e9jwQRb23nfa6c9d-StnImGyFDb")
$sbJwe.Append("Sv04uVuxIp5Zms1gNxKKK2Da14B8S4rzVRltdYwam_lDp5XnZAYpQdb76FdIKLaV")
$sbJwe.Append("mqgfwX7XWRxv2322i-vDxRfqNzo_tETKzpVLzfiwQyeyPGLBIO56YJ7eObdv0je8")
$sbJwe.Append("1860ppamavo35UgoRdbYaBcoh9QcfylQr66oc6vFWXRcZ_ZT2LawVCWTIy3brGPi")
$sbJwe.Append("6UklfCpIMfIjf7iGdXKHzg.")
$sbJwe.Append("48V1_ALb6US04U3b.")
$sbJwe.Append("5eym8TW_c8SuK0ltJ3rpYIzOeDQz7TALvtu6UG9oMo4vpzs9tX_EFShS8iB7j6ji")
$sbJwe.Append("SdiwkIr3ajwQzaBtQD_A.")
$sbJwe.Append("XFBoMYUZodetZdvTiFvSkQ")

$success = $jwe2.LoadJweSb($sbJwe)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

# Provide the RSA private key for decryption.
$jwe2.SetPrivateKey(0,$rsaPrivKey)

# Decrypt.
$originalPlaintext = $jwe2.Decrypt(0,"utf-8")
if ($jwe2.LastMethodSuccess -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$($originalPlaintext)