Visual FoxPro

MIME S/MIME Encryption Algorithm Properties

Demonstrates the properties that control S/MIME encryption: Pkcs7CryptAlg (the symmetric content-encryption algorithm), Pkcs7KeyLength (the content-encryption key length in bits), OaepPadding (whether RSAES-OAEP key transport is used instead of RSAES-PKCS1-v1_5), and the OAEP hash settings OaepHash and OaepMgfHash. The properties are configured before calling Encrypt.

Background. CMS/PKCS #7 encryption uses a symmetric algorithm to protect the content and an RSA key-transport scheme to protect the symmetric key. The defaults (aes, 128-bit, PKCS1-v1_5 padding) work broadly; these properties tune the algorithms and padding.

Chilkat Visual FoxPro Downloads

Download Chilkat for Visual FoxPro

Visual FoxPro

LOCAL lnSuccess
LOCAL loMime
LOCAL loCert

lnSuccess = 0

loMime = CreateObject('Chilkat.Mime')
lnSuccess = loMime.SetBodyFromPlainText("This message will be encrypted.")
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    CANCEL
ENDIF

*  Pkcs7CryptAlg is the symmetric content-encryption algorithm.  Supported values are aes, aes-gcm,
*  des, 3des, and rc2.  The default is aes.
loMime.Pkcs7CryptAlg = "aes"

*  Pkcs7KeyLength is the content-encryption key length in bits.  The default is 128.
loMime.Pkcs7KeyLength = 256

*  OaepPadding selects the RSA key-transport padding.  The default is 0 (RSAES-PKCS1-v1_5).
*  Set 1 to use RSAES-OAEP, in which case the OAEP hash settings apply.
loMime.OaepPadding = 1
loMime.OaepHash = "sha256"
loMime.OaepMgfHash = "sha256"

*  Load the recipient certificate (public key is sufficient for encrypting).
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadFromFile("qa_data/recipient.cer")
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loMime
    RELEASE loCert
    CANCEL
ENDIF

*  Encrypt using the algorithm settings configured above.
lnSuccess = loMime.Encrypt(loCert)
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    RELEASE loCert
    CANCEL
ENDIF

? "Encrypted with " + loMime.Pkcs7CryptAlg + " " + STR(loMime.Pkcs7KeyLength) + "-bit key."

RELEASE loMime
RELEASE loCert