(Lianja) RSAES-OAEP Encrypt String with AES-128 Content Encryption and SHA256

Encrypts a string using RSAES-OAEP with SHA256 and AES-128 content encryption to produce PKCS7 output (base64 encoded).

Note: This example requires Chilkat v9.5.0.67 or greater.

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// This example requires the Chilkat Crypt API to have been previously unlocked.
// See Unlock Chilkat Crypt for sample code.

// First build a string to be encrypted
loSb = createobject("CkStringBuilder")
i = 1
do while i < 25
    loSb.AppendInt(i)
    loSb.Append(" the quick brown fox jumped over the lazy dog." + Chr(13) + Chr(10))
    i = i + 1
enddo

? loSb.GetAsString()

// The string to be encrypted looks like this:

// 1 the quick brown fox jumped over the lazy dog.
// 2 the quick brown fox jumped over the lazy dog.
// 3 the quick brown fox jumped over the lazy dog.
// 4 the quick brown fox jumped over the lazy dog.
// 5 the quick brown fox jumped over the lazy dog.
// 6 the quick brown fox jumped over the lazy dog.
// ...

// Load a digital certificate. 
// We don't need the private key for encryption.
// Only the public key is needed (which is included in a certificate).
loCert = createobject("CkCert")
llSuccess = loCert.LoadFromFile("qa_data/rsaes-oaep/cert.pem")
if (llSuccess <> .T.) then
    ? loCert.LastErrorText
    release loSb
    release loCert
    return
endif

loCrypt = createobject("CkCrypt2")

// Tell the crypt object to use the certificate.
loCrypt.SetEncryptCert(loCert)

// Indicate that we want PKI encryption (i.e. public-key infrastructure)
// to produce a CMS message (Cryptographic Message Syntax/PKCS7),
// that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
// bulk encryption.
loCrypt.CryptAlgorithm = "pki"
loCrypt.Pkcs7CryptAlg = "aes"
loCrypt.KeyLength = 128
loCrypt.OaepHash = "sha256"
loCrypt.OaepPadding = .T.

// Also, don't forget to be specific about the character encoding (byte representation) of the
// string to be encrypted.
loCrypt.Charset = "utf-8"

// Now indicate that the PKCS7 output is to be returned in the base64 encoding.
loCrypt.EncodingMode = "base64"

lcBase64Pkcs7 = loCrypt.EncryptStringENC(loSb.GetAsString())
if (loCrypt.LastMethodSuccess <> .T.) then
    ? loCrypt.LastErrorText
    release loSb
    release loCert
    release loCrypt
    return
endif

// Show the output
? lcBase64Pkcs7

// This base64 can be copy-and-pasted into the form at http://lapo.it/asn1js/
// to verify that all the chosen algorithms were indeed used.

? "OK."


release loSb
release loCert
release loCrypt