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

See more Apple Keychain Examples

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

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

# 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.

set cert [new_CkCert]

# Set the token/smartcard PIN prior to loading.
CkCert_put_SmartCardPin $cert "123456"

# Specify the certificate by its common name.
set success [CkCert_LoadFromSmartcard $cert "cn=chilkat-rsa-2048"]
if {$success == 0} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkCert $cert
    exit
}

puts "Signing with cert: [CkCert_subjectCN $cert]"

# Create a string to be hashed and signed.
set sb [new_CkStringBuilder]

set crlfLineEnding 1

for {set i 0} {$i <= 10} {incr i} {
    CkStringBuilder_AppendLine $sb "This is a test." $crlfLineEnding
}

set rsa [new_CkRsa]

# Use the certificate's private key for signing.
set success [CkRsa_SetX509Cert $rsa $cert 1]
if {$success == 0} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkCert $cert
    delete_CkStringBuilder $sb
    delete_CkRsa $rsa
    exit
}

# Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
# Return the signature in base64 format.
CkRsa_put_EncodingMode $rsa "base64"
CkRsa_put_Charset $rsa "utf-8"
set stringToSign [CkStringBuilder_getAsString $sb]
set sigBase64 [CkRsa_signStringENC $rsa $stringToSign "sha256"]
if {[CkRsa_get_LastMethodSuccess $rsa] == 0} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkCert $cert
    delete_CkStringBuilder $sb
    delete_CkRsa $rsa
    exit
}

puts "RSA signature as base64: $sigBase64"

delete_CkCert $cert
delete_CkStringBuilder $sb
delete_CkRsa $rsa