(Tcl) RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature.

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

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

set privKey [new_CkPrivateKey]

# Load the private key from an RSA .key file:
set success [CkPrivateKey_LoadPemFile $privKey "privateKey.key"]
if {$success != 1} then {
    puts [CkPrivateKey_lastErrorText $privKey]
    delete_CkPrivateKey $privKey
    exit
}

# Get the private key in XML format:
set privKeyXml [CkPrivateKey_getXml $privKey]

set rsa [new_CkRsa]

# Import the private key into the RSA component:
set success [CkRsa_ImportPrivateKey $rsa $privKeyXml]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkPrivateKey $privKey
    delete_CkRsa $rsa
    exit
}

# Create the signature as a hex string:
CkRsa_put_EncodingMode $rsa "hex"

set strData "This is the string to be signed."

# Sign the string using the sha-1 hash algorithm.
# Other valid choices are "md2", "sha256", "sha384",
# "sha512", and "md5".
set hexSig [CkRsa_signStringENC $rsa $strData "sha-1"]

puts "$hexSig"

# Load a digital certificate from a .cer file:
set cert [new_CkCert]

set success [CkCert_LoadFromFile $cert "myCert.cer"]
if {$success != 1} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkPrivateKey $privKey
    delete_CkRsa $rsa
    delete_CkCert $cert
    exit
}

# pubKey is a CkPublicKey

set pubKey [CkCert_ExportPublicKey $cert]

# Now verify using a separate instance of the RSA object:
set rsa2 [new_CkRsa]

# Import the public key into the RSA object:
set success [CkRsa_ImportPublicKey $rsa2 [CkPublicKey_getXml $pubKey]]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa2]
    delete_CkPrivateKey $privKey
    delete_CkRsa $rsa
    delete_CkCert $cert
    delete_CkRsa $rsa2
    exit
}

delete_CkPublicKey $pubKey

# The signature is a hex string, so make sure the EncodingMode is correct:
CkRsa_put_EncodingMode $rsa2 "hex"

# Verify the signature:
set success [CkRsa_VerifyStringENC $rsa2 $strData "sha-1" $hexSig]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa2]
    delete_CkPrivateKey $privKey
    delete_CkRsa $rsa
    delete_CkCert $cert
    delete_CkRsa $rsa2
    exit
}

puts "Success."

delete_CkPrivateKey $privKey
delete_CkRsa $rsa
delete_CkCert $cert
delete_CkRsa $rsa2