(Lianja) JWS Using RSASSA-PSS using SHA-256 and MGF1 with SHA-256

Creates and validates a JSON Web Signature (JWS) using RSASSA-PSS using SHA-256 and MGF1 with SHA-256.

Chilkat supports all of the following JWS algorithms:

   +--------------+-------------------------------+--------------------+
   | "alg" Param  | Digital Signature or MAC      | Implementation     |
   | Value        | Algorithm                     | Requirements       |
   +--------------+-------------------------------+--------------------+
   | HS256        | HMAC using SHA-256            | Required           |
   | HS384        | HMAC using SHA-384            | Optional           |
   | HS512        | HMAC using SHA-512            | Optional           |
   | RS256        | RSASSA-PKCS1-v1_5 using       | Recommended        |
   |              | SHA-256                       |                    |
   | RS384        | RSASSA-PKCS1-v1_5 using       | Optional           |
   |              | SHA-384                       |                    |
   | RS512        | RSASSA-PKCS1-v1_5 using       | Optional           |
   |              | SHA-512                       |                    |
   | ES256        | ECDSA using P-256 and SHA-256 | Recommended+       |
   | ES384        | ECDSA using P-384 and SHA-384 | Optional           |
   | ES512        | ECDSA using P-521 and SHA-512 | Optional           |
   | PS256        | RSASSA-PSS using SHA-256 and  | Optional           |
   |              | MGF1 with SHA-256             |                    |
   | PS384        | RSASSA-PSS using SHA-384 and  | Optional           |
   |              | MGF1 with SHA-384             |                    |
   | PS512        | RSASSA-PSS using SHA-512 and  | Optional           |
   |              | MGF1 with SHA-512             |                    |
   +--------------+-------------------------------+--------------------+

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.

// Use the following RSA key loaded from JWK format.
loSbJwk = createobject("CkStringBuilder")
loSbJwk.Append('{"kty":"RSA",')
loSbJwk.Append('"n":"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx')
loSbJwk.Append("HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs")
loSbJwk.Append("D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH")
loSbJwk.Append("SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV")
loSbJwk.Append("MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8")
loSbJwk.Append('NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ",')
loSbJwk.Append('"e":"AQAB",')
loSbJwk.Append('"d":"Eq5xpGnNCivDflJsRQBXHx1hdR1k6Ulwe2JZD50LpXyWPEAeP88vLNO97I')
loSbJwk.Append("jlA7_GQ5sLKMgvfTeXZx9SE-7YwVol2NXOoAJe46sui395IW_GO-pWJ1O0")
loSbJwk.Append("BkTGoVEn2bKVRUCgu-GjBVaYLU6f3l9kJfFNS3E0QbVdxzubSu3Mkqzjkn")
loSbJwk.Append("439X0M_V51gfpRLI9JYanrC4D4qAdGcopV_0ZHHzQlBjudU2QvXt4ehNYT")
loSbJwk.Append("CBr6XCLQUShb1juUO1ZdiYoFaFQT5Tw8bGUl_x_jTj3ccPDVZFD9pIuhLh")
loSbJwk.Append('BOneufuBiB4cS98l2SR_RQyGWSeWjnczT0QU91p1DhOVRuOopznQ",')
loSbJwk.Append('"p":"4BzEEOtIpmVdVEZNCqS7baC4crd0pqnRH_5IB3jw3bcxGn6QLvnEtfdUdi')
loSbJwk.Append("YrqBdss1l58BQ3KhooKeQTa9AB0Hw_Py5PJdTJNPY8cQn7ouZ2KKDcmnPG")
loSbJwk.Append('BY5t7yLc1QlQ5xHdwW1VhvKn-nXqhJTBgIPgtldC-KDV5z-y2XDwGUc",')
loSbJwk.Append('"q":"uQPEfgmVtjL0Uyyx88GZFF1fOunH3-7cepKmtH4pxhtCoHqpWmT8YAmZxa')
loSbJwk.Append("ewHgHAjLYsp1ZSe7zFYHj7C6ul7TjeLQeZD_YwD66t62wDmpe_HlB-TnBA")
loSbJwk.Append('-njbglfIsRLtXlnDzQkv5dTltRJ11BKBBypeeF6689rjcJIDEz9RWdc",')
loSbJwk.Append('"dp":"BwKfV3Akq5_MFZDFZCnW-wzl-CCo83WoZvnLQwCTeDv8uzluRSnm71I3Q')
loSbJwk.Append("CLdhrqE2e9YkxvuxdBfpT_PI7Yz-FOKnu1R6HsJeDCjn12Sk3vmAktV2zb")
loSbJwk.Append('34MCdy7cpdTh_YVr7tss2u6vneTwrA86rZtu5Mbr1C1XsmvkxHQAdYo0",')
loSbJwk.Append('"dq":"h_96-mK1R_7glhsum81dZxjTnYynPbZpHziZjeeHcXYsXaaMwkOlODsWa')
loSbJwk.Append("7I9xXDoRwbKgB719rrmI2oKr6N3Do9U0ajaHF-NKJnwgjMd2w9cjz3_-ky")
loSbJwk.Append('NlxAr2v4IKhGNpmM5iIgOS1VZnOZ68m6_pbLBSp3nssTdlqvd0tIiTHU",')
loSbJwk.Append('"qi":"IYd7DHOhrWvxkwPQsRM2tOgrjbcrfvtQJipd-DlcxyVuuM9sQLdgjVk2o')
loSbJwk.Append("y26F0EmpScGLq2MowX7fhd_QJQ3ydy5cY7YIBi87w93IKLEdfnbJtoOPLU")
loSbJwk.Append('W0ITrJReOgo1cq9SbsxYawBgfp_gh6A5603k2-ZQwVK0JKSHuLFkuQ3U"')
loSbJwk.Append("}")

loRsaKey = createobject("CkPrivateKey")
// Note: This example loads the RSA key from JWK format.  Any format can be loaded
// into the private key object. (See the online reference documentation..)
llSuccess = loRsaKey.LoadJwk(loSbJwk.GetAsString())
if (llSuccess <> .T.) then
    ? loRsaKey.LastErrorText
    release loSbJwk
    release loRsaKey
    return
endif

// Create the JWS Protected Header
loJwsProtHdr = createobject("CkJsonObject")
loJwsProtHdr.AppendString("alg","PS256")

loJws = createobject("CkJws")

// Set the protected header:
lnSignatureIndex = 0
loJws.SetProtectedHeader(lnSignatureIndex,loJwsProtHdr)

// Set the RSA key:
loJws.SetPrivateKey(lnSignatureIndex,loRsaKey)

// Set the payload.
llBIncludeBom = .F.
lcPayloadStr = "In our village, folks say God crumbles up the old moon into stars."
loJws.SetPayload(lcPayloadStr,"utf-8",llBIncludeBom)

// Create the JWS
// By default, the compact serialization is used.
lcJwsCompact = loJws.CreateJws()
if (loJws.LastMethodSuccess <> .T.) then
    ? loJws.LastErrorText
    release loSbJwk
    release loRsaKey
    release loJwsProtHdr
    release loJws
    return
endif

? "JWS: " + lcJwsCompact

// Note: RSA PSS padding uses random values, so the output will be different each time a signature is produced.
// sample output:
// JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

// Now load the JWS, validate, and recover the original text.
loJws2 = createobject("CkJws")

// Load the JWS.
llSuccess = loJws2.LoadJws(lcJwsCompact)

loRsaPubKey = loRsaKey.GetPublicKey()

// Set the RSA public key used for validation.
lnSignatureIndex = 0
loJws2.SetPublicKey(lnSignatureIndex,loRsaPubKey)
release loRsaPubKey

// Validate the 1st (and only) signature at index 0..
v = loJws2.Validate(lnSignatureIndex)
if (v < 0) then
    // Perhaps Chilkat was not unlocked or the trial expired..
    ? "Method call failed for some other reason."
    ? loJws2.LastErrorText
    release loSbJwk
    release loRsaKey
    release loJwsProtHdr
    release loJws
    release loJws2
    return
endif

if (v = 0) then
    ? "Invalid signature.  The RSA key was incorrect, the JWS was invalid, or both."
    release loSbJwk
    release loRsaKey
    release loJwsProtHdr
    release loJws
    release loJws2
    return
endif

// If we get here, the signature was validated..
? "Signature validated."

// Recover the original content:
? loJws2.GetPayload("utf-8")

// Examine the protected header:
loJoseHeader = loJws2.GetProtectedHeader(lnSignatureIndex)
if (loJws2.LastMethodSuccess <> .T.) then
    ? "No protected header found at the given index."
    release loSbJwk
    release loRsaKey
    release loJwsProtHdr
    release loJws
    release loJws2
    return
endif

loJoseHeader.EmitCompact = .F.

? "Protected (JOSE) header:"
? loJoseHeader.Emit()
release loJoseHeader

// Output:

// 	Signature validated.
// 	In our village, folks say God crumbles up the old moon into stars.
// 	Protected (JOSE) header:
// 	{ 
// 	  "alg": "PS256"
// 	}


release loSbJwk
release loRsaKey
release loJwsProtHdr
release loJws
release loJws2