(Lianja) RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

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Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format.

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// Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
// this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

// Chilkat automatically detects and determines the way in which the HSM is used,
// which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

loCert = createobject("CkCert")

// Set the token/smartcard PIN prior to loading.
loCert.SmartCardPin = "123456"

// Specify the certificate by its common name.
llSuccess = loCert.LoadFromSmartcard("cn=chilkat-rsa-2048")
if (llSuccess = .F.) then
    ? loCert.LastErrorText
    release loCert
    return
endif

? "Signing with cert: " + loCert.SubjectCN

// Create a string to be hashed and signed.
loSb = createobject("CkStringBuilder")
llCrlfLineEnding = .T.

for i = 0 to 10
    loSb.AppendLine("This is a test.",llCrlfLineEnding)
next

loRsa = createobject("CkRsa")

// Use the certificate's private key for signing.
llSuccess = loRsa.SetX509Cert(loCert,.T.)
if (llSuccess = .F.) then
    ? loRsa.LastErrorText
    release loCert
    release loSb
    release loRsa
    return
endif

// Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
// Return the signature in base64 format.
loRsa.EncodingMode = "base64"
loRsa.Charset = "utf-8"
lcStringToSign = loSb.GetAsString()
lcSigBase64 = loRsa.SignStringENC(lcStringToSign,"sha256")
if (loRsa.LastMethodSuccess = .F.) then
    ? loRsa.LastErrorText
    release loCert
    release loSb
    release loRsa
    return
endif

? "RSA signature as base64: " + lcSigBase64


release loCert
release loSb
release loRsa