(Tcl) RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

Demonstrates how to RSA encrypt using RSA/ECB/OAEPWithSHA1AndMGF1Padding. Also demonstrates RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Both of these terms are from Java's JCE. Note: In this context, "ECB" doesn't actually mean anything. It's a symmetric cipher mode that doesn't apply (or make sense) in this context.

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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]

# First load a public key object with a public key.
# In this case, we'll load it from a file.
set pubkey [new_CkPublicKey]

set success [CkPublicKey_LoadFromFile $pubkey "qa_data/pem/rsa_public.pem"]
if {$success != 1} then {
    puts [CkPublicKey_lastErrorText $pubkey]
    delete_CkRsa $rsa
    delete_CkPublicKey $pubkey
    exit
}

# RSA encryption is limited to small amounts of data. The limit
# is typically a few hundred bytes and is based on the key size and
# padding (OAEP vs. PKCS1_5).  RSA encryption is typically used for
# encrypting hashes or symmetric (bulk encryption algorithm) secret keys.
set plainText "Time is an illusion. Lunchtime doubly so."

# Import the public key to be used for encrypting.
set success [CkRsa_ImportPublicKeyObj $rsa $pubkey]

# To get OAEP padding, set the OaepPadding property:
CkRsa_put_OaepPadding $rsa 1

# To use SHA1 or SHA-256, set the OaepHash property
CkRsa_put_OaepHash $rsa "sha256"
# for SHA1 --
CkRsa_put_OaepHash $rsa "sha1"

# Indicate we'll want hex output
CkRsa_put_EncodingMode $rsa "hex"

# Encrypt..
set usePrivateKey 0
set encryptedStr [CkRsa_encryptStringENC $rsa $plainText $usePrivateKey]
puts "$encryptedStr"

# -------------------------------------------------
# Now decrypt with the matching private key.
set rsa2 [new_CkRsa]

set privKey [new_CkPrivateKey]

set success [CkPrivateKey_LoadEncryptedPem $privKey "qa_data/pem/rsa_passwd.pem" "passwd"]
if {$success != 1} then {
    puts [CkPrivateKey_lastErrorText $privKey]
    delete_CkRsa $rsa
    delete_CkPublicKey $pubkey
    delete_CkRsa $rsa2
    delete_CkPrivateKey $privKey
    exit
}

set success [CkRsa_ImportPrivateKeyObj $rsa2 $privKey]

# Make sure we have the same settings used for encryption.
CkRsa_put_OaepPadding $rsa2 1
CkRsa_put_EncodingMode $rsa2 "hex"
CkRsa_put_OaepHash $rsa2 "sha1"

set originalStr [CkRsa_decryptStringENC $rsa2 $encryptedStr 1]

puts "$originalStr"

delete_CkRsa $rsa
delete_CkPublicKey $pubkey
delete_CkRsa $rsa2
delete_CkPrivateKey $privKey