PowerBuilder

Verify an RSA Signature Against the Signed Hash

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the hash that was signed. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Bd
integer i
string ls_Sha256_base64
string ls_Base64_rsa_sig
oleobject loo_PubKey
oleobject loo_Rsa

li_Success = 0

loo_Bd = create oleobject
li_rc = loo_Bd.ConnectToNewObject("Chilkat.BinData")
if li_rc < 0 then
    destroy loo_Bd
    MessageBox("Error","Connecting to COM object failed")
    return
end if

for i = 0 to 100
    loo_Bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex")
next
ls_Sha256_base64 = loo_Bd.GetHash("sha256","base64")
Write-Debug "sha256 hash in base64 format: " + ls_Sha256_base64

ls_Base64_rsa_sig = "AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w=="

// Get the public key to be used for signature verification.
loo_PubKey = create oleobject
li_rc = loo_PubKey.ConnectToNewObject("Chilkat.PublicKey")

li_Success = loo_PubKey.LoadFromFile("rsaKeys/chilkat-rsa-2048.pem")
if li_Success = 0 then
    Write-Debug loo_PubKey.LastErrorText
    destroy loo_Bd
    destroy loo_PubKey
    return
end if

loo_Rsa = create oleobject
li_rc = loo_Rsa.ConnectToNewObject("Chilkat.Rsa")

li_Success = loo_Rsa.UsePublicKey(loo_PubKey)
if li_Success = 0 then
    Write-Debug loo_Rsa.LastErrorText
    destroy loo_Bd
    destroy loo_PubKey
    destroy loo_Rsa
    return
end if

// Verify the hash against the signature.
loo_Rsa.EncodingMode = "base64"
li_Success = loo_Rsa.VerifyHashENC(ls_Sha256_base64,"sha256",ls_Base64_rsa_sig)

if li_Success = 0 then
    Write-Debug loo_Rsa.LastErrorText
    Write-Debug "Signature invalid."
else
    Write-Debug "Signature valid."
end if



destroy loo_Bd
destroy loo_PubKey
destroy loo_Rsa