(Tcl) Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

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

set pubKey [new_CkPublicKey]

# Load the public key from an PEM file:
set success [CkPublicKey_LoadFromFile $pubKey "pubKey.pem"]
if {$success != 1} then {
    puts [CkPublicKey_lastErrorText $pubKey]
    delete_CkPublicKey $pubKey
    exit
}

# Load the data of the original file that was signed.
set bdFileData [new_CkBinData]

set success [CkBinData_LoadFile $bdFileData "in.dat"]

# Load the signature.
set bdSig [new_CkBinData]

set success [CkBinData_LoadFile $bdSig "signature.sig"]

set rsa [new_CkRsa]

# Import the public key into the RSA component:
set success [CkRsa_ImportPublicKeyObj $rsa $pubKey]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkPublicKey $pubKey
    delete_CkBinData $bdFileData
    delete_CkBinData $bdSig
    delete_CkRsa $rsa
    exit
}

# OpenSSL uses big-endian.
CkRsa_put_LittleEndian $rsa 0

set success [CkRsa_VerifyBd $rsa $bdFileData "sha256" $bdSig]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa]
    puts "The signature was invalid."
    delete_CkPublicKey $pubKey
    delete_CkBinData $bdFileData
    delete_CkBinData $bdSig
    delete_CkRsa $rsa
    exit
}

puts "The signature was verified."

delete_CkPublicKey $pubKey
delete_CkBinData $bdFileData
delete_CkBinData $bdSig
delete_CkRsa $rsa