(Tcl) RSA Encrypt and Decrypt Strings

Tcl sample code to RSA public-key encrypt and decrypt strings using public and private keys.

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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 rsa [new_CkRsa]

# This example also generates the public and private
# keys to be used in the RSA encryption.
# Normally, you would generate a key pair once,
# and distribute the public key to your partner.
# Anything encrypted with the public key can be
# decrypted with the private key.  The reverse is 
# also true: anything encrypted using the private
# key can be decrypted using the public key.

# Generate a 1024-bit key.  Chilkat RSA supports
# key sizes ranging from 512 bits to 4096 bits.
set success [CkRsa_GenerateKey $rsa 1024]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkRsa $rsa
    exit
}

# Keys are exported in XML format:
set publicKey [CkRsa_exportPublicKey $rsa]
set privateKey [CkRsa_exportPrivateKey $rsa]

set plainText "Encrypting and decrypting should be easy!"

# Start with a new RSA object to demonstrate that all we
# need are the keys previously exported:
set rsaEncryptor [new_CkRsa]

# Encrypted output is always binary.  In this case, we want
# to encode the encrypted bytes in a printable string.
# Our choices are "hex", "base64", "url", "quoted-printable".
CkRsa_put_EncodingMode $rsaEncryptor "hex"

# We'll encrypt with the public key and decrypt with the private
# key.  It's also possible to do the reverse.
set success [CkRsa_ImportPublicKey $rsaEncryptor $publicKey]

set usePrivateKey 0
set encryptedStr [CkRsa_encryptStringENC $rsaEncryptor $plainText $usePrivateKey]
puts "$encryptedStr"

# Now decrypt:
set rsaDecryptor [new_CkRsa]

CkRsa_put_EncodingMode $rsaDecryptor "hex"
set success [CkRsa_ImportPrivateKey $rsaDecryptor $privateKey]

set usePrivateKey 1
set decryptedStr [CkRsa_decryptStringENC $rsaDecryptor $encryptedStr $usePrivateKey]

puts "$decryptedStr"

delete_CkRsa $rsa
delete_CkRsa $rsaEncryptor
delete_CkRsa $rsaDecryptor