B4X

Ed25519ph Sign and Verify

See more Ed25519 Examples

Demonstrates how to create an Ed25519ph signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.91 or greater.

B4X

Dim success As Boolean = False

'  This example assumes the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  Use the following test vector from https://www.rfc-editor.org/rfc/rfc8032#page-30

'     -----TEST abc
'  
'     ALGORITHM:
'     Ed25519ph
'  
'     SECRET KEY:
'     833fe62409237b9d62ec77587520911e
'     9a759cec1d19755b7da901b96dca3d42
'  
'     PUBLIC KEY:
'     ec172b93ad5e563bf4932c70e1245034
'     c35467ef2efd4d64ebf819683467e2bf
'  
'     MESSAGE (length 3 bytes):
'     616263
'  
'     SIGNATURE:
'     98a70222f0b8121aa9d30f813d683f80
'     9e462b469c7ff87639499bb94e6dae41
'     31f85042463c2a355a2003d062adf5aa
'     a10b8c61e636062aaad11c2a26083406

Dim privKeyHex As String = "833fe62409237b9d62ec77587520911e9a759cec1d19755b7da901b96dca3d42"
Dim pubKeyHex As String = "ec172b93ad5e563bf4932c70e1245034c35467ef2efd4d64ebf819683467e2bf"

Dim privKey As ChilkatPrivateKey
privKey.Initialize("privKey")
success = privKey.LoadEd25519(privKeyHex, pubKeyHex)
If success = False Then
    Log(privKey.LastErrorText)
    Return
End If


'  The data to be signed...
Dim bd As ChilkatBinData
bd.Initialize
bd.AppendEncoded("616263", "hex")

Dim eddsa As ChilkatEdDSA
eddsa.Initialize
'  Indicate we want the Ed25519ph instance.
eddsa.Algorithm = "Ed25519ph"

Dim hexSig As String = eddsa.SignBdENC(bd, "hexlower", privKey)

Log("signature = " & hexSig)

'  The expected output is: 98a70222f0b8121aa9d30f813d683f80....

'  Verify the signature..
Dim pubKey As ChilkatPublicKey
pubKey.Initialize
success = pubKey.LoadEd25519(pubKeyHex)
If success = False Then
    Log(pubKey.LastErrorText)
    Return
End If


Dim bVerified As Boolean = eddsa.VerifyBdENC(bd, hexSig, "hexlower", pubKey)
If bVerified = False Then
    Log(eddsa.LastErrorText)
    Log("Failed to verify the signature.")
    Return
End If


Log("The Ed25519ph signature is verified!")