(Lianja) 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.

Chilkat Lianja Extension Download Chilkat Lianja Extension

// 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.

lcPlaintext = "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"}
loJweProtHdr = createobject("CkJsonObject")
loJweProtHdr.AppendString("alg","RSA-OAEP")
loJweProtHdr.AppendString("enc","A256GCM")
? "JWE Protected Header: " + loJweProtHdr.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:
loSbJwk = createobject("CkStringBuilder")
loSbJwk.Append('{"kty": "RSA",')
loSbJwk.Append('"n": "oahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E-BVvxkeDNjbC4he8rUW')
loSbJwk.Append("cJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3S")
loSbJwk.Append("psk_ZkoFnilakGygTwpZ3uesH-PFABNIUYpOiN15dsQRkgr0vEhxN92i2a")
loSbJwk.Append("sbOenSZeyaxziK72UwxrrKoExv6kc5twXTq4h-QChLOln0_mtUZwfsRaMS")
loSbJwk.Append("tPs6mS6XrgxnxbWhojf663tuEQueGC-FCMfra36C9knDFGzKsNa7LZK2dj")
loSbJwk.Append('YgyD3JR_MB_4NUJW_TqOQtwHYbxevoJArm-L5StowjzGy-_bq6Gw",')
loSbJwk.Append('"e": "AQAB",')
loSbJwk.Append('"d": "kLdtIj6GbDks_ApCSTYQtelcNttlKiOyPzMrXHeI-yk1F7-kpDxY4-WY5N')
loSbJwk.Append("WV5KntaEeXS1j82E375xxhWMHXyvjYecPT9fpwR_M9gV8n9Hrh2anTpTD9")
loSbJwk.Append("3Dt62ypW3yDsJzBnTnrYu1iwWRgBKrEYY46qAZIrA2xAwnm2X7uGR1hghk")
loSbJwk.Append("qDp0Vqj3kbSCz1XyfCs6_LehBwtxHIyh8Ripy40p24moOAbgxVw3rxT_vl")
loSbJwk.Append("t3UVe4WO3JkJOzlpUf-KTVI2Ptgm-dARxTEtE-id-4OJr0h-K-VFs3VSnd")
loSbJwk.Append('VTIznSxfyrj8ILL6MG_Uv8YAu7VILSB3lOW085-4qE3DzgrTjgyQ",')
loSbJwk.Append('"p": "1r52Xk46c-LsfB5P442p7atdPUrxQSy4mti_tZI3Mgf2EuFVbUoDBvaRQ-')
loSbJwk.Append("SWxkbkmoEzL7JXroSBjSrK3YIQgYdMgyAEPTPjXv_hI2_1eTSPVZfzL0lf")
loSbJwk.Append('fNn03IXqWF5MDFuoUYE0hzb2vhrlN_rKrbfDIwUbTrjjgieRbwC6Cl0",')
loSbJwk.Append('"q": "wLb35x7hmQWZsWJmB_vle87ihgZ19S8lBEROLIsZG4ayZVe9Hi9gDVCOBm')
loSbJwk.Append("UDdaDYVTSNx_8Fyw1YYa9XGrGnDew00J28cRUoeBB_jKI1oma0Orv1T9aX")
loSbJwk.Append('IWxKwd4gvxFImOWr3QRL9KEBRzk2RatUBnmDZJTIAfwTs0g68UZHvtc",')
loSbJwk.Append('"dp": "ZK-YwE7diUh0qR1tR7w8WHtolDx3MZ_OTowiFvgfeQ3SiresXjm9gZ5KL')
loSbJwk.Append("hMXvo-uz-KUJWDxS5pFQ_M0evdo1dKiRTjVw_x4NyqyXPM5nULPkcpU827")
loSbJwk.Append('rnpZzAJKpdhWAgqrXGKAECQH0Xt4taznjnd_zVpAmZZq60WPMBMfKcuE",')
loSbJwk.Append('"dq": "Dq0gfgJ1DdFGXiLvQEZnuKEN0UUmsJBxkjydc3j4ZYdBiMRAy86x0vHCj')
loSbJwk.Append("ywcMlYYg4yoC4YZa9hNVcsjqA3FeiL19rk8g6Qn29Tt0cj8qqyFpz9vNDB")
loSbJwk.Append('UfCAiJVeESOjJDZPYHdHY8v1b-o-Z2X5tvLx-TCekf7oxyeKDUqKWjis",')
loSbJwk.Append('"qi": "VIMpMYbPf47dT1w_zDUXfPimsSegnMOA1zTaX7aGk_8urY6R8-ZW1FxU7')
loSbJwk.Append("AlWAyLWybqq6t16VFd7hQd0y6flUK4SlOydB61gwanOsXGOAOv82cHq0E3")
loSbJwk.Append('eL4HrtZkUuKvnPrMnsUUFlfUdybVzxyjz9JF_XyaY14ardLSjf4L_FNY"}')

// Load this JWK into a Chilkat private key object.
loRsaPrivKey = createobject("CkPrivateKey")
llSuccess = loRsaPrivKey.LoadJwk(loSbJwk.GetAsString())
if (llSuccess <> .T.) then
    ? loRsaPrivKey.LastErrorText
    release loJweProtHdr
    release loSbJwk
    release loRsaPrivKey
    return
endif

// 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
loRsaPubKey = loRsaPrivKey.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).

loJwe = createobject("CkJwe")
loJwe.SetProtectedHeader(loJweProtHdr)
loJwe.SetPublicKey(0,loRsaPubKey)
release loRsaPubKey

lcStrJwe = loJwe.Encrypt(lcPlaintext,"utf-8")
if (loJwe.LastMethodSuccess <> .T.) then
    ? loJwe.LastErrorText
    release loJweProtHdr
    release loSbJwk
    release loRsaPrivKey
    release loJwe
    return
endif

// 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.)
? lcStrJwe

// 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.
loJwe2 = createobject("CkJwe")
llSuccess = loJwe2.LoadJwe(lcStrJwe)
if (llSuccess <> .T.) then
    ? loJwe2.LastErrorText
    release loJweProtHdr
    release loSbJwk
    release loRsaPrivKey
    release loJwe
    release loJwe2
    return
endif

// Provide the RSA private key for decryption.
// (The JWE was encrypted for a single recipient at index 0.)
loJwe2.SetPrivateKey(0,loRsaPrivKey)

// Decrypt.
lcOriginalPlaintext = loJwe2.Decrypt(0,"utf-8")
if (loJwe2.LastMethodSuccess <> .T.) then
    ? loJwe2.LastErrorText
    release loJweProtHdr
    release loSbJwk
    release loRsaPrivKey
    release loJwe
    release loJwe2
    return
endif

? "original text: "
? lcOriginalPlaintext

// ---------------------------------------------------------------------------------
// 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.

loSbJwe = createobject("CkStringBuilder")
loSbJwe.Append("eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ.")
loSbJwe.Append("OKOawDo13gRp2ojaHV7LFpZcgV7T6DVZKTyKOMTYUmKoTCVJRgckCL9kiMT03JGe")
loSbJwe.Append("ipsEdY3mx_etLbbWSrFr05kLzcSr4qKAq7YN7e9jwQRb23nfa6c9d-StnImGyFDb")
loSbJwe.Append("Sv04uVuxIp5Zms1gNxKKK2Da14B8S4rzVRltdYwam_lDp5XnZAYpQdb76FdIKLaV")
loSbJwe.Append("mqgfwX7XWRxv2322i-vDxRfqNzo_tETKzpVLzfiwQyeyPGLBIO56YJ7eObdv0je8")
loSbJwe.Append("1860ppamavo35UgoRdbYaBcoh9QcfylQr66oc6vFWXRcZ_ZT2LawVCWTIy3brGPi")
loSbJwe.Append("6UklfCpIMfIjf7iGdXKHzg.")
loSbJwe.Append("48V1_ALb6US04U3b.")
loSbJwe.Append("5eym8TW_c8SuK0ltJ3rpYIzOeDQz7TALvtu6UG9oMo4vpzs9tX_EFShS8iB7j6ji")
loSbJwe.Append("SdiwkIr3ajwQzaBtQD_A.")
loSbJwe.Append("XFBoMYUZodetZdvTiFvSkQ")

llSuccess = loJwe2.LoadJweSb(loSbJwe)
if (llSuccess <> .T.) then
    ? loJwe2.LastErrorText
    release loJweProtHdr
    release loSbJwk
    release loRsaPrivKey
    release loJwe
    release loJwe2
    release loSbJwe
    return
endif

// Provide the RSA private key for decryption.
loJwe2.SetPrivateKey(0,loRsaPrivKey)

// Decrypt.
lcOriginalPlaintext = loJwe2.Decrypt(0,"utf-8")
if (loJwe2.LastMethodSuccess <> .T.) then
    ? loJwe2.LastErrorText
    release loJweProtHdr
    release loSbJwk
    release loRsaPrivKey
    release loJwe
    release loJwe2
    release loSbJwe
    return
endif

? lcOriginalPlaintext


release loJweProtHdr
release loSbJwk
release loRsaPrivKey
release loJwe
release loJwe2
release loSbJwe