CryptoSys PKI Pro Manual

Kdf.ForCms Method

Generate a key-encryption key (KEK) for ECDH key exchange in a CMS EnvelopedData object.

Syntax

[C#]
public static byte[] ForCms(
   byte[] zz,
   Kdf.KeyWrapAlg keyWrapAlg,
   Kdf.KdfAlg kdfAlg = Kdf.KdfAlg.X963,
   Kdf.HashAlg hashAlg = Kdf.HashAlg.Sha1,
   byte[] ukm = null 
)
[VB]
Public Shared Function ForCms (
   zz As Byte(),
   keyWrapAlg As Kdf.KeyWrapAlg,
   Optional kdfAlg As Kdf.KdfAlg = Kdf.KdfAlg.X963,
   Optional hashAlg As Kdf.HashAlg = Kdf.HashAlg.Sha1,
   Optional ukm As Byte() = Nothing 
) As Byte()

Parameters

zz  Byte
Input key material/shared secret value (denoted variously as ZZ/Z/K/IKM)
keyWrapAlg  Kdf.KeyWrapAlg
Key wrap algorithm (required, cannot be Default)
kdfAlg  Kdf.KdfAlg  (Optional)
Key derivation function to use.
hashAlg  Kdf.HashAlg  (Optional)
Hash algorithm to use with the key derivation function (default is SHA-1)
ukm  Byte  (Optional)
Optional user key material (ukm)

Return Value

Byte
Output key material (KEK).

Remarks

This is a specialist function using the key definition algorithms described in [RFC5753] and [RFC8418] when used for key agreement with ECDH in a CMS EnvelopedData object. The key-encryption key is derived using the ECC-CMS-SharedInfo type, described in section 7.2 of [RFC5753].

See Also

VB6/C equivalent: KDF_ForCms

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