rsaDecodeMsg

Decode an EME or EMSA encoded message block according to PKCS#1.

Syntax

Public Function rsaDecodeMsg ( _
    lpInput() As Byte, _
    nOptions As Long _
) As Byte()

Parameters

lpInput

Data to be decoded.

nOptions

Include one of the following:

PKI_EME_PKCSV1_5
PKI_EME_OAEP
PKI_EMSIG_PKCSV1_5

If you have selected PKI_EMSIG_PKCSV1_5, then you can add PKI_EMSIG_DIGINFO to decode an 'Encoded Message for Signature' block and output the whole DigestInfo data instead of just the message digest.
If you have selected PKI_EME_OAEP, then add one of these options to match the hash function used for EME-OAEP encoding:

PKI_HASH_SHA1
PKI_HASH_SHA224
PKI_HASH_SHA256
PKI_HASH_SHA384
PKI_HASH_SHA512

and optionally add PKI_MGF_MGF1SHA1 to force the MGF hash function to be SHA-1 (default = same as encoding hash function set above).
Alternatively, ignore all the above and use the specialist option PKI_EMSIG_ISO9796 to use the ISO9796-1 encoding for a signature.

Return Value

Remarks