Xbase++ Requires Chilkat v11.0.0+

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. Xbase++

LOCAL nSuccess
LOCAL oBd
LOCAL i
LOCAL cSha256_base64
LOCAL cBase64_rsa_sig
LOCAL oPubKey
LOCAL oRsa

nSuccess := 0

oBd := CreateObject("Chilkat.BinData")

FOR i := 0 TO 100
    oBd:AppendEncoded("000102030405060708090A0B0C0D0E0F", "hex")
NEXT
cSha256_base64 := oBd:GetHash("sha256", "base64")
? "sha256 hash in base64 format: " + cSha256_base64

cBase64_rsa_sig := "AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w=="

//  Get the public key to be used for signature verification.
oPubKey := CreateObject("Chilkat.PublicKey")
nSuccess := oPubKey:LoadFromFile("rsaKeys/chilkat-rsa-2048.pem")
IF (nSuccess == 0)
    ? oPubKey:LastErrorText
    oBd:destroy()
    oPubKey:destroy()
    RETURN
ENDIF

oRsa := CreateObject("Chilkat.Rsa")
nSuccess := oRsa:UsePublicKey(oPubKey)
IF (nSuccess == 0)
    ? oRsa:LastErrorText
    oBd:destroy()
    oPubKey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  Verify the hash against the signature.
oRsa:EncodingMode := "base64"
nSuccess := oRsa:VerifyHashENC(cSha256_base64, "sha256", cBase64_rsa_sig)

IF (nSuccess == 0)
    ? oRsa:LastErrorText
    ? "Signature invalid."
ELSE
    ? "Signature valid."
ENDIF

oBd:destroy()
oPubKey:destroy()
oRsa:destroy()