(Visual FoxPro) RSASSA-PSS Sign Text

Signs text to create a PKCS7/CMS signature. The signature algorithm is RSASSA-PSS with SHA256.

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loCrypt
LOCAL loPfx
LOCAL lnSuccess
LOCAL loCert
LOCAL loSb
LOCAL i
LOCAL lcPkcs7sig

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Crypt2')
loCrypt = CreateObject('Chilkat.Crypt2')

* Get a digital certificate with private key from a .pfx
* (Chilkat has many different ways to provide a cert + private key for siging.
* Using a PFX is just one possible option.)
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Pfx')
loPfx = CreateObject('Chilkat.Pfx')
lnSuccess = loPfx.LoadPfxFile("qa_data/rsassa-pss/privatekey.pfx","PFX_PASSWORD")
IF (lnSuccess <> 1) THEN
    ? loPfx.LastErrorText
    RELEASE loCrypt
    RELEASE loPfx
    CANCEL
ENDIF

* Get the certificate to be used for signing.
* (The typical case for a PFX is that it contains a cert with an associated private key,
* as well as other certificates in the chain of authentication.  The cert with the private
* key should be in the first position at index 0.)
loCert = loPfx.GetCert(0)
IF (loPfx.LastMethodSuccess <> 1) THEN
    ? loPfx.LastErrorText
    RELEASE loCrypt
    RELEASE loPfx
    CANCEL
ENDIF

loCrypt.SetSigningCert(loCert)

* Indicate that RSASSA-PSS with SHA256 should be used.
loCrypt.SigningAlg = "pss"
loCrypt.HashAlgorithm = "sha256"

loCrypt.EncodingMode = "base64_mime"

* Build a string to sign
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSb = CreateObject('Chilkat.StringBuilder')
i = 1
DO WHILE i < 12
    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.
* ...

* Make sure to specify the byte representation (character encoding)
loCrypt.Charset = "utf-8"

* Sign the string to get a PKCS7 detached signature in base64 format.
lcPkcs7sig = loCrypt.SignSbENC(loSb)
? "Detached PCKS7 Signature:"
? lcPkcs7sig

* This signature looks like this:

* MIIG5wYJKoZIhvcNAQcCoIIG2DCCBtQCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
* ggL4MIIC9DCCAl2gAwIBAgIJAMPsJCT11cniMA0GCSqGSIb3DQEBCwUAMIGSMQswCQYDVQQGEwJB
* VTERMA8GA1UECAwIVmljdG9yaWExEjAQBgNVBAcMCU1lbGJvdXJuZTEhMB8GA1UECgwYSW50ZXJu
* ZXQgV2lkZ2l0cyBQdHkgTHRkMQ8wDQYDVQQDDAZXaWRnZXQxKDAmBgkqhkiG9w0BCQEWGWFkbWlu
* QGludGVybmV0d2lkZ2V0cy5jb20wHhcNMTYxMTAxMTY1MjMyWhcNMjExMDMxMTY1MjMyWjCBkjEL
* MAkGA1UEBhMCQVUxETAPBgNVBAgMCFZpY3RvcmlhMRIwEAYDVQQHDAlNZWxib3VybmUxITAfBgNV
* BAoMGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEPMA0GA1UEAwwGV2lkZ2V0MSgwJgYJKoZIhvcN
* AQkBFhlhZG1pbkBpbnRlcm5ldHdpZGdldHMuY29tMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKB
* gQDGIdoCjyavs+F/Rm0VIB4m6O7VL1j+1IqieoR9NEX2GQvu2VCdceyxf9qaw1bxipEvjLwUkw7M
* e+BTlLpWQbBMH87s6KpsC8MVyXhMLpP0oM8NFix/vLz2wdLhUh7CZvJA0plqkJk9bj57QIu+EO1k
* tUHM2DFb6sckvCL2yybD1wIDAQABo1AwTjAdBgNVHQ4EFgQUONKKu2zsXIrinWxIGT654vrcQwsw
* HwYDVR0jBBgwFoAUONKKu2zsXIrinWxIGT654vrcQwswDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0B
* AQsFAAOBgQArFvdi5u9i2QF1Qw+cdC1l7w2Y3+q6RIkln2W8rWJFje00644o8hXy7v46giJCedmF
* ULlhm1n7XIsZGy2W3lJ77v5agn9gFwXu1h3cqkGXkoteE6SQJQXWgsW3GWPveObvTL8LF4y57fgM
* 9ZWS+V9MJajeu44Rf/tU17TLYKjvEjGCA7MwggOvAgEBMIGgMIGSMQswCQYDVQQGEwJBVTERMA8G
* A1UECAwIVmljdG9yaWExEjAQBgNVBAcMCU1lbGJvdXJuZTEhMB8GA1UECgwYSW50ZXJuZXQgV2lk
* Z2l0cyBQdHkgTHRkMQ8wDQYDVQQDDAZXaWRnZXQxKDAmBgkqhkiG9w0BCQEWGWFkbWluQGludGVy
* bmV0d2lkZ2V0cy5jb20CCQDD7CQk9dXJ4jANBglghkgBZQMEAgEFAKCCAjQwGAYJKoZIhvcNAQkD
* MQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTcwNDI5MTYzNTQ3WjAvBgkqhkiG9w0BCQQx
* IgQgnXqtpfBjs9ZZUJxbNYbwYvpmXTGgIbYErkIA3jQo0EEwXwYJKoZIhvcNAQkPMVIwUDALBglg
* hkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFAMAcGBSsO
* AwIHMA0GCCqGSIb3DQMCAgEoMIGxBgkrBgEEAYI3EAQxgaMwgaAwgZIxCzAJBgNVBAYTAkFVMREw
* DwYDVQQIDAhWaWN0b3JpYTESMBAGA1UEBwwJTWVsYm91cm5lMSEwHwYDVQQKDBhJbnRlcm5ldCBX
* aWRnaXRzIFB0eSBMdGQxDzANBgNVBAMMBldpZGdldDEoMCYGCSqGSIb3DQEJARYZYWRtaW5AaW50
* ZXJuZXR3aWRnZXRzLmNvbQIJAMPsJCT11cniMIGzBgsqhkiG9w0BCRACCzGBo6CBoDCBkjELMAkG
* A1UEBhMCQVUxETAPBgNVBAgMCFZpY3RvcmlhMRIwEAYDVQQHDAlNZWxib3VybmUxITAfBgNVBAoM
* GEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEPMA0GA1UEAwwGV2lkZ2V0MSgwJgYJKoZIhvcNAQkB
* FhlhZG1pbkBpbnRlcm5ldHdpZGdldHMuY29tAgkAw+wkJPXVyeIwPQYJKoZIhvcNAQEKMDCgDTAL
* BglghkgBZQMEAgGhGjAYBgkqhkiG9w0BAQgwCwYJYIZIAWUDBAIBogMCASAEgYBFgBS1vtBoac6P
* /NRcY3jdytoxK7xc8vEYW/PhgsbE+sP7dvu6eoRLVicoQ8RIeMh3CtPZFq1+JcL5NNzQoAotizTX
* EKhiceX1mC5ocCeEvgNouxkN2Qr/X12m60rNvNl5r+GEqiqx/1fs2yRAl5sIzwPsMMY3p9tGOpy0
* 5p7sRQ==

* The ASN.1 of the signature can be examined by browsing to https://lapo.it/asn1js/ ,
* then copy-and-paste the Base64 signature into the form and decode..

* The signature can be verified against the original data like this:
lnSuccess = loCrypt.VerifySbENC(loSb,lcPkcs7sig)
? "Signature verified: " + STR(lnSuccess)

RELEASE loCert

RELEASE loCrypt
RELEASE loPfx
RELEASE loSb