B4X Requires Chilkat v11.0.0+
B4X
Validate JWS with Multiple Signatures using the General JSON Serialization Format
See more JSON Web Signatures (JWS) Examples
Validates and recovers data and headers from a JSON Web Signature (JWS) containing 3 signatures.Note: 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 | | +--------------+-------------------------------+--------------------+
Chilkat B4X Downloads
Dim success As Boolean = False
' This requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.
' First, prepare the public keys that will be needed for each signature.
' ---------------------------------------------------
' Use the following RSA key loaded from JWK format.
Dim sbRsaJwk As ChilkatStringBuilder
sbRsaJwk.Initialize
sbRsaJwk.Append("{" & Chr(34) & "kty" & Chr(34) & ":" & Chr(34) & "RSA" & Chr(34) & ",")
sbRsaJwk.Append(Chr(34) & "n" & Chr(34) & ":" & Chr(34) & "ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx")
sbRsaJwk.Append("HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs")
sbRsaJwk.Append("D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH")
sbRsaJwk.Append("SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV")
sbRsaJwk.Append("MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8")
sbRsaJwk.Append("NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ" & Chr(34) & ",")
sbRsaJwk.Append(Chr(34) & "e" & Chr(34) & ":" & Chr(34) & "AQAB" & Chr(34))
sbRsaJwk.Append("}")
Dim rsaKey As ChilkatPublicKey
rsaKey.Initialize
success = rsaKey.LoadFromString(sbRsaJwk.GetAsString)
If success = False Then
Log(rsaKey.LastErrorText)
Return
End If
' ---------------------------------------------------
' Use the following ECC public key loaded from JWK format.
Dim sbEccJwk As ChilkatStringBuilder
sbEccJwk.Initialize
sbEccJwk.Append("{" & Chr(34) & "kty" & Chr(34) & ":" & Chr(34) & "EC" & Chr(34) & ",")
sbEccJwk.Append(Chr(34) & "crv" & Chr(34) & ":" & Chr(34) & "P-256" & Chr(34) & ",")
sbEccJwk.Append(Chr(34) & "x" & Chr(34) & ":" & Chr(34) & "f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU" & Chr(34) & ",")
sbEccJwk.Append(Chr(34) & "y" & Chr(34) & ":" & Chr(34) & "x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" & Chr(34))
sbEccJwk.Append("}")
Dim eccKey As ChilkatPublicKey
eccKey.Initialize
success = eccKey.LoadFromString(sbEccJwk.GetAsString)
If success = False Then
Log(eccKey.LastErrorText)
Return
End If
' ---------------------------------------------------
' The HMAC key (in base64url format)
Dim hmacKey As String = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
' The code below will verify each of the signatures in this JWS:
' {
' "payload": "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu",
' "signatures": [
' {
' "protected": "eyJhbGciOiJSUzI1NiIsImtpZCI6Im15UnNhS2V5In0",
' "signature": "IPMQ02niTQDwLzsRZSCaEm9VEyAX_AVe3HWjniNt9kW-a8d6ZVbd2k6jGae8s1yIh0cgxDnXQ6-p6_sBI0cnMO0xpuJANhh2vFtNJl5lisad94-H3mB3lSfafRqxeYp5D8bh39BPv7y3PrUNVMQdKEJp_D5oJ0ROPTIYx3EG8eJQOx1HO0KqhcUo401XR6KSsIyFm5joBLNKTVzxZUTT1RRZZtwTdeZkbGevugIOX_9gHAtARpV6WaFA4Vvjnq8X9wPgqjWNCQRupadhTPz0JAsa-wy5vXQjsFlXAn43mDPpMfna5Ab3F5pS4yDwkbX6nRn7XBxH1SnnNJRFholQZw"
' },
' {
' "protected": "eyJhbGciOiJFUzI1NiIsImtpZCI6Im15RWNLZXkifQ",
' "signature": "1OQtaT3pgZmkDxvlfghvxL_8kX16WIen6u1MadEq1pA4qytA0--_EwZDNk00GDPWFpoJtKznibMZzLOg_UhHIw"
' },
' {
' "protected": "eyJhbGciOiJIUzI1NiIsImtpZCI6Im15TWFjS2V5In0",
' "signature": "YY8yVjmJJfy7YJOn3uUydG8WCY2PEuCvOLil5Ks5lnw"
' }
' ]
' }
Dim sbJws As ChilkatStringBuilder
sbJws.Initialize
sbJws.Append("{ ")
sbJws.Append(" " & Chr(34) & "payload" & Chr(34) & ": " & Chr(34) & "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu" & Chr(34) & ",")
sbJws.Append(" " & Chr(34) & "signatures" & Chr(34) & ": [")
sbJws.Append(" { ")
sbJws.Append(" " & Chr(34) & "protected" & Chr(34) & ": " & Chr(34) & "eyJhbGciOiJSUzI1NiIsImtpZCI6Im15UnNhS2V5In0" & Chr(34) & ",")
sbJws.Append(" " & Chr(34) & "signature" & Chr(34) & ": " & Chr(34) & "IPMQ02niTQDwLzsRZSCaEm9VEyAX_AVe3HWjniNt9kW-a8d6ZVbd2k6jGae8s1yIh0cgxDnXQ6-p6_sBI0cnMO0xpuJANhh2vFtNJl5lisad94-H3mB3lSfafRqxeYp5D8bh39BPv7y3PrUNVMQdKEJp_D5oJ0ROPTIYx3EG8eJQOx1HO0KqhcUo401XR6KSsIyFm5joBLNKTVzxZUTT1RRZZtwTdeZkbGevugIOX_9gHAtARpV6WaFA4Vvjnq8X9wPgqjWNCQRupadhTPz0JAsa-wy5vXQjsFlXAn43mDPpMfna5Ab3F5pS4yDwkbX6nRn7XBxH1SnnNJRFholQZw" & Chr(34))
sbJws.Append(" },")
sbJws.Append(" { ")
sbJws.Append(" " & Chr(34) & "protected" & Chr(34) & ": " & Chr(34) & "eyJhbGciOiJFUzI1NiIsImtpZCI6Im15RWNLZXkifQ" & Chr(34) & ",")
sbJws.Append(" " & Chr(34) & "signature" & Chr(34) & ": " & Chr(34) & "1OQtaT3pgZmkDxvlfghvxL_8kX16WIen6u1MadEq1pA4qytA0--_EwZDNk00GDPWFpoJtKznibMZzLOg_UhHIw" & Chr(34))
sbJws.Append(" },")
sbJws.Append(" { ")
sbJws.Append(" " & Chr(34) & "protected" & Chr(34) & ": " & Chr(34) & "eyJhbGciOiJIUzI1NiIsImtpZCI6Im15TWFjS2V5In0" & Chr(34) & ",")
sbJws.Append(" " & Chr(34) & "signature" & Chr(34) & ": " & Chr(34) & "YY8yVjmJJfy7YJOn3uUydG8WCY2PEuCvOLil5Ks5lnw" & Chr(34))
sbJws.Append(" }")
sbJws.Append(" ]")
sbJws.Append("}")
Dim jws As ChilkatJws
jws.Initialize
success = jws.LoadJwsSb(sbJws)
If success = False Then
Log(jws.LastErrorText)
Return
End If
' The payload is easily accessible:
Log("Payload: " & jws.GetPayload("utf-8"))
Dim sbKeyId As ChilkatStringBuilder
sbKeyId.Initialize
Dim bCaseSensitive As Boolean = False
Dim protHeader As ChilkatJsonObject
protHeader.Initialize
Dim numSignatures As Int = jws.NumSignatures
Dim i As Int = 0
Do While i < numSignatures
success = jws.GetProtectedH(i, protHeader)
If success = False Then
Log(jws.LastErrorText)
Return
End If
Log("--------------------------")
Log(i & ": ")
' Get the protected header.
protHeader.EmitCompact = False
Log(protHeader.Emit)
' Get the key ID ("kid") member.
' Note: In this example, the "kid" values are contained in the protected headers.
' They could've just as easily been located in unprotected headers. In that case,
' we would've called GetUnprotectedH instead of GetProtectedH(i).
sbKeyId.Clear
sbKeyId.Append(protHeader.StringOf("kid"))
' Set the key based on key ID.
If sbKeyId.ContentsEqual("myRsaKey", bCaseSensitive) = True Then
jws.SetPublicKey(i, rsaKey)
End If
If sbKeyId.ContentsEqual("myEcKey", bCaseSensitive) = True Then
jws.SetPublicKey(i, eccKey)
End If
If sbKeyId.ContentsEqual("myMacKey", bCaseSensitive) = True Then
jws.SetMacKey(i, hmacKey, "base64url")
End If
' Validate this signature.
Dim v As Int = jws.Validate(i)
If v < 0 Then
' Perhaps Chilkat was not unlocked or the trial expired..
Log("Validate failed for some other reason.")
Log(jws.LastErrorText)
Else
If v = 0 Then
Log("Invalid signature. The key was incorrect, the JWS was invalid, or both.")
Else
Log("Signature validated.")
End If
End If
i = i + 1
Loop
' The output of this program is:
' Payload: In our village, folks say God crumbles up the old moon into stars.
' --------------------------
' 0:
' {
' "alg": "RS256",
' "kid": "myRsaKey"
' }
'
' Signature validated.
' --------------------------
' 1:
' {
' "alg": "ES256",
' "kid": "myEcKey"
' }
'
' Signature validated.
' --------------------------
' 2:
' {
' "alg": "HS256",
' "kid": "myMacKey"
' }
'
' Signature validated.