(Tcl) Sign JSON (or any Text) to Create a Detached PKCS7 Signature

Demonstrates how to sign JSON or any string using a certificate + private key from a .p12/.pfx to create a detached PKCS7 signature. (A detached signature is one that does not embed the original signed data.)

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load ./chilkat.dll

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

set crypt [new_CkCrypt2]

set cert [new_CkCert]

set success [CkCert_LoadPfxFile $cert "qa_data/pfx/cert_test123.pfx" "test123"]
if {$success != 1} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

# Tell the crypt component to use this cert.
set success [CkCrypt2_SetSigningCert $crypt $cert]
if {$success != 1} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

CkCrypt2_put_HashAlgorithm $crypt "sha256"

# By default, all the certs in the chain of authentication are included in the signature.
# If desired, we can choose to only include the signing certificate:
CkCrypt2_put_IncludeCertChain $crypt 0

# Create the detached signature, which does NOT contain the original data.
# To create a PKCS7 signature that contains the original data, see CAdES Sign JSON
CkCrypt2_put_Charset $crypt "utf-8"
set detachedSig [new_CkByteData]

set stringToSign "{ \"abc\": 123}"
set success [CkCrypt2_SignString $crypt $stringToSign $detachedSig]
if {[CkCrypt2_get_LastMethodSuccess $crypt] == 0} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    delete_CkByteData $detachedSig
    exit
}

# Verify the signature against the original data.
set verified [CkCrypt2_VerifyString $crypt $stringToSign $detachedSig]
if {$verified == 0} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    delete_CkByteData $detachedSig
    exit
}

puts "Success!"

delete_CkCrypt2 $crypt
delete_CkCert $cert
delete_CkByteData $detachedSig