(Lianja) JWE using RSAES-PKCS1-v1_5 and AES_128_CBC_HMAC_SHA_256

This example duplicates the example A.2 in RFC 7516 for JSON Web Encryption (JWE).

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

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// 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 = "Live long and prosper."

// First build the JWE Protected Header.
// We want to build this: {"alg":"RSA1_5","enc":"A128CBC-HS256"}
loJweProtHdr = createobject("CkJsonObject")
loJweProtHdr.AppendString("alg","RSA1_5")
loJweProtHdr.AppendString("enc","A128CBC-HS256")
? "JWE Protected Header: " + loJweProtHdr.Emit()
? "--"

// The specific RSA key used in the A.2 example is the following JWK:
loSbJwk = createobject("CkStringBuilder")
loSbJwk.Append('{"kty":"RSA",')
loSbJwk.Append('"n":"sXchDaQebHnPiGvyDOAT4saGEUetSyo9MKLOoWFsueri23bOdgWp4Dy1Wl')
loSbJwk.Append("UzewbgBHod5pcM9H95GQRV3JDXboIRROSBigeC5yjU1hGzHHyXss8UDpre")
loSbJwk.Append("cbAYxknTcQkhslANGRUZmdTOQ5qTRsLAt6BTYuyvVRdhS8exSZEy_c4gs_")
loSbJwk.Append("7svlJJQ4H9_NxsiIoLwAEk7-Q3UXERGYw_75IDrGA84-lA_-Ct4eTlXHBI")
loSbJwk.Append("Y2EaV7t7LjJaynVJCpkv4LKjTTAumiGUIuQhrNhZLuF_RJLqHpM2kgWFLU")
loSbJwk.Append('7-VTdL1VbC2tejvcI2BlMkEpk1BzBZI0KQB0GaDWFLN-aEAw3vRw",')
loSbJwk.Append('"e":"AQAB",')
loSbJwk.Append('"d":"VFCWOqXr8nvZNyaaJLXdnNPXZKRaWCjkU5Q2egQQpTBMwhprMzWzpR8Sxq')
loSbJwk.Append("1OPThh_J6MUD8Z35wky9b8eEO0pwNS8xlh1lOFRRBoNqDIKVOku0aZb-ry")
loSbJwk.Append("nq8cxjDTLZQ6Fz7jSjR1Klop-YKaUHc9GsEofQqYruPhzSA-QgajZGPbE_")
loSbJwk.Append("0ZaVDJHfyd7UUBUKunFMScbflYAAOYJqVIVwaYR5zWEEceUjNnTNo_CVSj")
loSbJwk.Append("-VvXLO5VZfCUAVLgW4dpf1SrtZjSt34YLsRarSb127reG_DUwg9Ch-Kyvj")
loSbJwk.Append('T1SkHgUWRVGcyly7uvVGRSDwsXypdrNinPA4jlhoNdizK2zF2CWQ",')
loSbJwk.Append('"p":"9gY2w6I6S6L0juEKsbeDAwpd9WMfgqFoeA9vEyEUuk4kLwBKcoe1x4HG68')
loSbJwk.Append("ik918hdDSE9vDQSccA3xXHOAFOPJ8R9EeIAbTi1VwBYnbTp87X-xcPWlEP")
loSbJwk.Append('krdoUKW60tgs1aNd_Nnc9LEVVPMS390zbFxt8TN_biaBgelNgbC95sM",')
loSbJwk.Append('"q":"uKlCKvKv_ZJMVcdIs5vVSU_6cPtYI1ljWytExV_skstvRSNi9r66jdd9-y')
loSbJwk.Append("BhVfuG4shsp2j7rGnIio901RBeHo6TPKWVVykPu1iYhQXw1jIABfw-MVsN")
loSbJwk.Append('-3bQ76WLdt2SDxsHs7q7zPyUyHXmps7ycZ5c72wGkUwNOjYelmkiNS0",')
loSbJwk.Append('"dp":"w0kZbV63cVRvVX6yk3C8cMxo2qCM4Y8nsq1lmMSYhG4EcL6FWbX5h9yuv')
loSbJwk.Append("ngs4iLEFk6eALoUS4vIWEwcL4txw9LsWH_zKI-hwoReoP77cOdSL4AVcra")
loSbJwk.Append('Hawlkpyd2TWjE5evgbhWtOxnZee3cXJBkAi64Ik6jZxbvk-RR3pEhnCs",')
loSbJwk.Append('"dq":"o_8V14SezckO6CNLKs_btPdFiO9_kC1DsuUTd2LAfIIVeMZ7jn1Gus_Ff')
loSbJwk.Append("7B7IVx3p5KuBGOVF8L-qifLb6nQnLysgHDh132NDioZkhH7mI7hPG-PYE_")
loSbJwk.Append('odApKdnqECHWw0J-F0JWnUd6D2B_1TvF9mXA2Qx-iGYn8OVV1Bsmp6qU",')
loSbJwk.Append('"qi":"eNho5yRBEBxhGBtQRww9QirZsB66TrfFReG_CcteI1aCneT0ELGhYlRlC')
loSbJwk.Append("tUkTRclIfuEPmNsNDPbLoLqqCVznFbvdB7x-Tl-m0l_eFTj2KiqwGqE9PZ")
loSbJwk.Append('B9nNTwMVvH3VRRSLWACvPnSiwP8N5Usy-WRXS-V7TbpxIhvepTfE0NNo"')
loSbJwk.Append("}")

// 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()

// Create the JWE...
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

// Show the JWE we just created:
? lcStrJwe

// Note: The RSA PKCS1_V1_5 padding uses random value, and the results
// will be different each time.  However, each result should be successfully
// decrypting if using the correct RSA private key.

// 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.2.7
// because it was produced using the same RSA key.

loSbJwe = createobject("CkStringBuilder")
loSbJwe.Append("eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.")
loSbJwe.Append("UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-kFm")
loSbJwe.Append("1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKxGHZ7Pc")
loSbJwe.Append("HALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3YvkkysZIF")
loSbJwe.Append("NPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPhcCdZ6XDP0_F8")
loSbJwe.Append("rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPgwCp6X-nZZd9OHBv")
loSbJwe.Append("-B3oWh2TbqmScqXMR4gp_A.")
loSbJwe.Append("AxY8DCtDaGlsbGljb3RoZQ.")
loSbJwe.Append("KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.")
loSbJwe.Append("9hH0vgRfYgPnAHOd8stkvw")

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