(Tcl) openssl enc decrypt

Demonstrates how to decrypt a file that was encrypted using "openssl enc".

This example shows how to decrypt what was created using this openssl command:

openssl enc -e -aes-256-cbc -in hamlet.xml -out hamlet.enc -pass file:./secret.txt

This example shows how to do this:

openssl enc -d -aes-256-cbc -in hamlet.enc -out hamlet_dec.xml -pass file:./secret.txt

Note: This example requires Chilkat v9.5.0.71 or later.

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 crypt [new_CkCrypt2]

# Use aes-256-cbc
CkCrypt2_put_CryptAlgorithm $crypt "aes"
CkCrypt2_put_CipherMode $crypt "cbc"
CkCrypt2_put_KeyLength $crypt 256

# We'll need to set the hash algorithm to either MD5 or SHA256.
# openssl version 1.0.* or earlier used MD5 by default
# openssl version 1.1.* uses SHA-256 for the password to secret key derivation.

# For example, if openssl 1.1.0 was used, we should do this:
CkCrypt2_put_HashAlgorithm $crypt "sha256"

# This example assumes openssl 1.0.2 was used to encrypt what we're now decrypting:
CkCrypt2_put_HashAlgorithm $crypt "md5"

# The openssl command we are duplicating is:
# 
#    openssl enc -d -aes-256-cbc -in hamlet.enc -out hamlet_dec.xml -pass file:./secret.txt
# 
# The file secret.txt contains the word "secret".  We could write code to load the contents
# of secret.txt, but instead we'll just do this:
CkCrypt2_SetSecretKeyViaPassword $crypt "secret"

# Load the file to be decrypted.
set fileData [new_CkBinData]

set success [CkBinData_LoadFile $fileData "qa_data/openssl_enc/hamlet.enc"]

# Decrypt
set success [CkCrypt2_DecryptBd $crypt $fileData]

# Save the decrypted output.
set success [CkBinData_WriteFile $fileData "qa_output/hamlet_dec.xml"]

puts "success = $success"

delete_CkCrypt2 $crypt
delete_CkBinData $fileData