Co-signatures

PKI SDK lets you group different signers of the same document in a single signature package. These parallel signatures are called co-signatures, and the CAdES standard provides for them.

The example below shows a basic co-signature:

// Previous basic CAdES signature
byte[] cadesSig1 = ...

// Co-signing the cadesSig1 signature
PKCertificateWithKey signingCert2 = ...
var signer2 = new CadesSigner();
signer2.SetSigningCertificate(signingCert2);
signer2.SetDataToSign(toSign);
signer2.SetPolicy(policy);

// Setting the previous signature to co-sign
signer2.SetSignatureToCoSign(cadesSig1);

signer2.ComputeSignature();

byte[] cadesCoSig = signer2.GetSignature();

note

If the cadesSig1 signature already has the signed document in its encapsulated content, you don't need to call @Lacuna.Pki.Cades.CadesSigner.SetDataToSign(System.Byte[]) on the co-signature.

If you have parallel signatures of the same document that were created without @Lacuna.Pki.Cades.CadesSigner.SetSignatureToCoSign(System.Byte[]), you can still merge them into a co-signature with the Lacuna.Pki.Cades.CadesSignatureEditor.MergeSignatures(IEnumerable<Lacuna.Pki.Cades.CadesSignature>) method of the @Lacuna.Pki.Cades.CadesSignatureEditor class.

See also​

See also