B4X Requires Chilkat v11.0.0+

RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

See more RSA Examples

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. B4X

Dim success As Boolean = False

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

Dim rsa As ChilkatRsa
rsa.Initialize

'  First load a public key object with a public key.
'  In this case, we'll load it from a file.
Dim pubkey As ChilkatPublicKey
pubkey.Initialize
success = pubkey.LoadFromFile("qa_data/pem/rsa_public.pem")
If success = False Then
    Log(pubkey.LastErrorText)
    Return
End If


'  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.
Dim plainText As String = "Time is an illusion. Lunchtime doubly so."

'  Import the public key to be used for encrypting.
success = rsa.UsePublicKey(pubkey)

'  To get OAEP padding, set the PkcsPadding property equal to False
rsa.PkcsPadding = False
rsa.OaepHash = "sha256"

'  Indicate we'll want hex output
rsa.EncodingMode = "hex"

'  Encrypt..
Dim usePrivateKey As Boolean = False
Dim encryptedStr As String = rsa.EncryptStringENC(plainText, usePrivateKey)
Log(encryptedStr)

'  -------------------------------------------------
'  Now decrypt with the matching private key.
Dim rsa2 As ChilkatRsa
rsa2.Initialize

Dim privKey As ChilkatPrivateKey
privKey.Initialize("privKey")
success = privKey.LoadEncryptedPem("qa_data/pem/rsa_passwd.pem", "passwd")
If success = False Then
    Log(privKey.LastErrorText)
    Return
End If


success = rsa2.UsePrivateKey(privKey)

'  Make sure we have the same settings used for encryption.
rsa2.PkcsPadding = False
rsa2.EncodingMode = "hex"
rsa2.OaepHash = "sha256"

Dim originalStr As String = rsa2.DecryptStringENC(encryptedStr, True)

Log(originalStr)