Added support for RSASSA-PSS and RSAES-OAEP.

README.md

@@ -14,12 +14,14 @@ It consists of the following packages
 - smime Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 [rfc5751-bis-12](https://tools.ietf.org/html/draft-ietf-lamps-rfc5751-bis-12) [![GoDoc](https://godoc.org/github.com/InfiniteLoopSpace/go_S-MIME/smime?status.svg)](https://godoc.org/github.com/InfiniteLoopSpace/go_S-MIME/smime)
 - timestamp<sup>[5]</sup> - Time-Stamp Protocol (TSP) [rfc3161](https://tools.ietf.org/html/rfc3161) [![GoDoc](https://godoc.org/github.com/InfiniteLoopSpace/go_S-MIME/timestamp?status.svg)](https://godoc.org/github.com/InfiniteLoopSpace/go_S-MIME/timestamp)
 
-It supports enveloped data with AES in CBC mode. Decryption also works with (3)DES.  Authenticated-Enveloped-Data Content Type is also supported with AES-GCM and ChaCha20-Poly1305.
+It supports enveloped data with AES in CBC mode. Decryption also works with (3)DES.  Authenticated-Enveloped-Data Content Type is also supported with AES-GCM and ChaCha20-Poly1305. Also RSAES-OAEP and RSASSA-PSS is supported.
 
 This is covered in 
 - Cryptographic Message Syntax (CMS) Authenticated-Enveloped-Data Content Type [rfc5083](https://tools.ietf.org/html/rfc5083)
 - Using ChaCha20-Poly1305 Authenticated Encryption in the Cryptographic Message Syntax (CMS) [rfc8103](https://tools.ietf.org/html/rfc8103)
 - Using AES-CCM and AES-GCM Authenticated Encryption in the Cryptographic Message Syntax (CMS) [rfc5084](https://tools.ietf.org/html/rfc5084)
+- Use of the RSASSA-PSS Signature Algorithm in Cryptographic Message Syntax (CMS) [rfc4056](https://tools.ietf.org/html/rfc4056)
+- Use of the RSAES-OAEP Key Transport Algorithm in the Cryptographic Message Syntax (CMS) [rfc3560](https://tools.ietf.org/html/rfc3560)
 
 ## Examples
 
@@ -53,8 +55,6 @@ plaintext, _ := SMIME.Verify(signedMsg)
 
 ## Todo
 
-- Add S/MIME capabilities attributes
-- Add ECDH for encryption and decryption
 - Testing
 
 

cms/cms.go

@@ -23,6 +23,7 @@ type CMS struct {
 	TimeStampServer            string
 	TimeStamp                  bool
 	keyPairs                   []tls.Certificate
+	signedAttrs                []protocol.Attribute
 }
 
 // New create a new instance of CMS with given keyPairs.
@@ -54,6 +55,19 @@ func New(cert ...tls.Certificate) (cms *CMS, err error) {
 	return
 }
 
+// AddAttribute adds a attribute to signedAttrs which will be used for signing
+func (cms *CMS) AddAttribute(attrType asn1.ObjectIdentifier, val interface{}) (err error) {
+
+	attr, err := protocol.NewAttribute(attrType, val)
+	if err != nil {
+		return
+	}
+
+	cms.signedAttrs = append(cms.signedAttrs, attr)
+
+	return
+}
+
 // Encrypt encrypts data for the recipients and returns DER-encoded ASN.1 ContentInfo.
 func (cms *CMS) Encrypt(data []byte, recipients []*x509.Certificate) (der []byte, err error) {
 
@@ -160,7 +174,10 @@ func (cms *CMS) Sign(data []byte, detachedSignature ...bool) (der []byte, err er
 	}
 
 	for i := range cms.keyPairs {
-		sd.AddSignerInfo(cms.keyPairs[i])
+		err = sd.AddSignerInfo(cms.keyPairs[i], cms.signedAttrs)
+		if err != nil {
+			return
+		}
 	}
 
 	if cms.TimeStamp {

cms/cms_test.go

@@ -29,50 +29,78 @@ var (
 		CommonName: "leaf.example.com",
 	}))
 
+	leafPSS = intermediate.Issue(pki.Subject(pkix.Name{
+		CommonName: "leaf.example.com",
+	}), pki.SignatureAlgorithm(x509.SHA256WithRSAPSS))
+
 	ecKey, _ = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
 
 	leafECC = intermediate.Issue(pki.Subject(pkix.Name{
 		CommonName: "leaf.example.com",
 	}), pki.PrivateKey(ecKey))
 
-	keyPair = tls.Certificate{
+	keyPairRSA = tls.Certificate{
 		Certificate: [][]byte{leaf.Certificate.Raw, intermediate.Certificate.Raw, root.Certificate.Raw},
 		PrivateKey:  leaf.PrivateKey.(crypto.PrivateKey),
 		Leaf:        leaf.Certificate,
 	}
 
+	keyPairRSAPSS = tls.Certificate{
+		Certificate: [][]byte{leafPSS.Certificate.Raw, intermediate.Certificate.Raw, root.Certificate.Raw},
+		PrivateKey:  leafPSS.PrivateKey.(crypto.PrivateKey),
+		Leaf:        leafPSS.Certificate,
+	}
+
 	keyPairECC = tls.Certificate{
 		Certificate: [][]byte{leafECC.Certificate.Raw, intermediate.Certificate.Raw, root.Certificate.Raw},
 		PrivateKey:  leafECC.PrivateKey.(crypto.PrivateKey),
 		Leaf:        leafECC.Certificate,
 	}
 
-	keyPairs = []tls.Certificate{}
+	keypair tls.Certificate
 
-	keyPairsOpenssl = []tls.Certificate{}
+	skipOpenssl = false
+
+	opensslSignOpts = []string{"-outform", "DER"}
+
+	opensslEncOpts = []string{"-outform", "DER"}
 )
 
 func TestMain(m *testing.M) {
-
+	// Test RSA
-	keyPairs = []tls.Certificate{keyPair, keyPairECC}
+	keypair = keyPairRSA
 
 	version, err := openssl.Openssl(nil, "version")
-
+	if err != nil {
-	if err == nil {
+		skipOpenssl = true
-		keyPairsOpenssl = append(keyPairsOpenssl, keyPair)
 	}
 
+	m.Run()
+
+	// Test RSA PSS OAEP
+	keypair = keyPairRSAPSS
+
 	if strings.HasPrefix(string(version), "OpenSSL 1.1") {
 		openssl.SMIME = "cms"
-		keyPairsOpenssl = append(keyPairsOpenssl, keyPairECC)
+	} else {
+		skipOpenssl = true
 	}
 
+	opensslSignOpts = append(opensslSignOpts, "-keyopt", "rsa_padding_mode:pss")
+	opensslEncOpts = append(opensslEncOpts, "-keyopt", "rsa_padding_mode:oaep")
+
+	m.Run()
+	opensslSignOpts = []string{"-outform", "DER"}
+	opensslEncOpts = []string{"-outform", "DER"}
+
+	// Test ECDDSA
+	keypair = keyPairECC
+
 	m.Run()
 }
 
 func TestAuthEnrypt(t *testing.T) {
 
-	for _, keypair := range keyPairs {
 	cms, err := New(keypair)
 	if err != nil {
 		t.Error(err)
@@ -94,11 +122,9 @@ func TestAuthEnrypt(t *testing.T) {
 		t.Fatal("Encryption and decryption are not inverse")
 	}
 }
-}
 
 func TestEnryptDecrypt(t *testing.T) {
 
-	for _, keypair := range keyPairs {
 	cms, err := New(keypair)
 	if err != nil {
 		t.Error(err)
@@ -119,12 +145,11 @@ func TestEnryptDecrypt(t *testing.T) {
 	if !bytes.Equal(plaintext, plain) {
 		t.Fatal("Encryption and decryption are not inverse")
 	}
-	}
+
 }
 
 func TestSignVerify(t *testing.T) {
 
-	for _, keypair := range keyPairs {
 	cms, err := New(keypair)
 	if err != nil {
 		t.Error(err)
@@ -144,14 +169,16 @@ func TestSignVerify(t *testing.T) {
 		t.Error(err)
 	}
 }
-}
 
 func TestEncryptOpenSSL(t *testing.T) {
 
-	for _, keypair := range keyPairsOpenssl {
+	if skipOpenssl {
+		return
+	}
+
 	message := []byte("Hallo Welt!")
 
-		der, err := openssl.Encrypt(message, keypair.Leaf, "-outform", "DER")
+	der, err := openssl.Encrypt(message, keypair.Leaf, opensslEncOpts...)
 	if err != nil {
 		t.Error(err)
 	}
@@ -165,12 +192,15 @@ func TestEncryptOpenSSL(t *testing.T) {
 	if !bytes.Equal(message, plain) {
 		t.Fatal("Encryption and decryption are not inverse")
 	}
-	}
+
 }
 
 func TestDecryptOpenSSL(t *testing.T) {
 
-	for _, keypair := range keyPairsOpenssl {
+	if skipOpenssl {
+		return
+	}
+
 	message := []byte("Hallo Welt!")
 
 	cms, _ := New()
@@ -187,15 +217,18 @@ func TestDecryptOpenSSL(t *testing.T) {
 	if !bytes.Equal(message, plain) {
 		t.Fatal("Encryption and decryption are not inverse")
 	}
-	}
+
 }
 
 func TestSignOpenSSL(t *testing.T) {
 
-	for _, keypair := range keyPairsOpenssl {
+	if skipOpenssl {
+		return
+	}
+
 	message := []byte("Hallo Welt")
 
-		sig, err := openssl.SignDetached(message, keypair.Leaf, keypair.PrivateKey, []*x509.Certificate{intermediate.Certificate}, "-outform", "DER")
+	sig, err := openssl.SignDetached(message, keypair.Leaf, keypair.PrivateKey, []*x509.Certificate{intermediate.Certificate}, opensslSignOpts...)
 	if err != nil {
 		t.Error(err)
 	}
@@ -211,11 +244,13 @@ func TestSignOpenSSL(t *testing.T) {
 		t.Error(err)
 	}
 }
-}
 
 func TestVerifyOpenSSL(t *testing.T) {
 
-	for _, keypair := range keyPairsOpenssl {
+	if skipOpenssl {
+		return
+	}
+
 	cms, err := New(keypair)
 	if err != nil {
 		t.Error(err)
@@ -241,4 +276,3 @@ func TestVerifyOpenSSL(t *testing.T) {
 		t.Fatal("Signed message and message do not agree!")
 	}
 }
-}

cms/protocol/pssoaep.go

@@ -0,0 +1,183 @@
+package protocol
+
+import (
+	"crypto"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"errors"
+
+	oid "github.com/InfiniteLoopSpace/go_S-MIME/oid"
+)
+
+type pssParameters struct {
+	Hash         pkix.AlgorithmIdentifier `asn1:"optional,explicit,tag:0"`
+	MGF          pkix.AlgorithmIdentifier `asn1:"optional,explicit,tag:1"`
+	SaltLength   int                      `asn1:"optional,explicit,tag:2"`
+	TrailerField int                      `asn1:"optional,explicit,tag:3"` //,default:1"`
+}
+
+var oidMGF1 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 8}
+
+func newpssParameters(hash ...crypto.Hash) (param pssParameters, err error) {
+
+	// SHA1 is default value
+	if len(hash) == 1 && hash[0] == crypto.SHA1 {
+		return
+	}
+
+	var h asn1.ObjectIdentifier
+
+	if len(hash) == 0 {
+		h = oid.DigestAlgorithmSHA1
+		param.SaltLength = 20
+		param.TrailerField = 1
+	} else {
+		var ok bool
+		h, ok = oid.HashToDigestAlgorithm[hash[0]]
+		if !ok {
+			err = errors.New("Unsupported hashfunction")
+		}
+	}
+
+	hRV, err := RawValue(pkix.AlgorithmIdentifier{Algorithm: h})
+	if err != nil {
+		return
+	}
+
+	param.Hash = pkix.AlgorithmIdentifier{Algorithm: h}
+
+	param.MGF = pkix.AlgorithmIdentifier{Algorithm: oidMGF1, Parameters: hRV}
+
+	return
+}
+
+// This is needed because CheckSignature uses PSSSaltLengthEqualsHash, if PSSSaltLengthAuto is used this code is not needed
+func verfiyRSAPSS(cert x509.Certificate, signatureAlgorithm pkix.AlgorithmIdentifier, signedMessage, signature []byte) (err error) {
+
+	param, err := newpssParameters()
+	if err != nil {
+		return
+	}
+
+	_, err = asn1.Unmarshal(signatureAlgorithm.Parameters.FullBytes, &param)
+	if err != nil {
+		return
+	}
+
+	if !param.MGF.Algorithm.Equal(oidMGF1) {
+		err = errors.New("Mask generator funktion not supported; only MGF1 is supported")
+		return
+	}
+
+	hash := oid.DigestAlgorithmToHash[param.Hash.Algorithm.String()]
+
+	pssOpts := rsa.PSSOptions{SaltLength: param.SaltLength, Hash: hash}
+
+	h := hash.New()
+	h.Write(signedMessage)
+	digest := h.Sum(nil)
+
+	err = rsa.VerifyPSS(cert.PublicKey.(*rsa.PublicKey), hash, digest, signature, &pssOpts)
+
+	return
+}
+
+func newPSS(hash crypto.Hash, pub *rsa.PublicKey) (signatureAlgorithm pkix.AlgorithmIdentifier, opts *rsa.PSSOptions, err error) {
+
+	opts = &rsa.PSSOptions{Hash: hash}
+
+	pssParam, err := newpssParameters(hash)
+	if err != nil {
+		return
+	}
+
+	pssParam.SaltLength = (pub.N.BitLen()+7)/8 - 2 - hash.Size() // https://golang.org/src/crypto/rsa/pss.go?s=6982:7095#L239
+
+	paramRV, err := RawValue(pssParam)
+	if err != nil {
+		return
+	}
+	signatureAlgorithm = pkix.AlgorithmIdentifier{Algorithm: oid.SignatureAlgorithmRSASSAPSS, Parameters: paramRV}
+	return
+}
+
+// RSAESOAEPparams  ::=  SEQUENCE  {
+//	hashFunc    [0] AlgorithmIdentifier DEFAULT sha1Identifier,
+//	maskGenFunc [1] AlgorithmIdentifier DEFAULT mgf1SHA1Identifier,
+//	pSourceFunc [2] AlgorithmIdentifier DEFAULT
+//						pSpecifiedEmptyIdentifier  }
+type RSAESOAEPparams struct {
+	HashFunc    pkix.AlgorithmIdentifier `asn1:"optional,explicit,tag:0"`
+	MaskGenFunc pkix.AlgorithmIdentifier `asn1:"optional,explicit,tag:1"`
+	PSourceFunc pkix.AlgorithmIdentifier `asn1:"optional,explicit,tag:2"`
+}
+
+var oidpSpecified = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 9}
+
+func newRSAESOAEPparams(hash ...crypto.Hash) (param RSAESOAEPparams, err error) {
+
+	// SHA1 is default value
+	if len(hash) == 1 && hash[0] == crypto.SHA1 {
+		return
+	}
+
+	nullOctetString, err := RawValue([]byte{})
+
+	var h asn1.ObjectIdentifier
+
+	if len(hash) == 0 {
+		h = oid.DigestAlgorithmSHA1
+	} else {
+		var ok bool
+		h, ok = oid.HashToDigestAlgorithm[hash[0]]
+		if !ok {
+			err = errors.New("Unsupported hashfunction")
+		}
+	}
+
+	hRV, err := RawValue(pkix.AlgorithmIdentifier{Algorithm: h})
+
+	param = RSAESOAEPparams{pkix.AlgorithmIdentifier{Algorithm: h, Parameters: asn1.NullRawValue},
+		pkix.AlgorithmIdentifier{Algorithm: oidMGF1, Parameters: hRV},
+		pkix.AlgorithmIdentifier{Algorithm: oidpSpecified, Parameters: nullOctetString}}
+
+	return
+}
+
+func parseRSAESOAEPparams(param []byte) (opts *rsa.OAEPOptions, err error) {
+	var oaepOpts RSAESOAEPparams
+	oaepOpts, err = newRSAESOAEPparams()
+	if err != nil {
+		return
+	}
+
+	_, err = asn1.Unmarshal(param, &oaepOpts)
+	if err != nil {
+		return
+	}
+
+	opts = &rsa.OAEPOptions{Hash: oid.DigestAlgorithmToHash[oaepOpts.HashFunc.Algorithm.String()], Label: []byte{}}
+
+	if !oaepOpts.MaskGenFunc.Algorithm.Equal(oidMGF1) {
+		err = errors.New("Unsupported mask generation funktion" + oaepOpts.MaskGenFunc.Algorithm.String())
+		return
+	}
+
+	if !oaepOpts.PSourceFunc.Algorithm.Equal(oidpSpecified) {
+		err = errors.New("Unsupported p source funktion" + oaepOpts.PSourceFunc.Algorithm.String())
+		return
+	}
+
+	return
+}
+
+func isRSAPSS(cert *x509.Certificate) bool {
+	switch cert.SignatureAlgorithm {
+	case x509.SHA256WithRSAPSS, x509.SHA384WithRSAPSS, x509.SHA512WithRSAPSS:
+		return true
+	default:
+		return false
+	}
+}

cms/protocol/reciepientinfo.go

@@ -10,7 +10,6 @@ import (
 	"crypto/x509/pkix"
 	"encoding/asn1"
 	"errors"
-	"fmt"
 	"log"
 	"time"
 
@@ -34,7 +33,7 @@ type RecipientInfo struct {
 func (recInfo *RecipientInfo) decryptKey(keyPair tls.Certificate) (key []byte, err error) {
 
 	key, err = recInfo.KTRI.decryptKey(keyPair)
-	if key != nil {
+	if key != nil || (err != nil && err != ErrUnsupported) {
 		return
 	}
 
@@ -64,6 +63,23 @@ func (ktri *KeyTransRecipientInfo) decryptKey(keyPair tls.Certificate) (key []by
 
 	ski := keyPair.Leaf.SubjectKeyId
 
+	certPubAlg := oid.PublicKeyAlgorithmToEncrytionAlgorithm[keyPair.Leaf.PublicKeyAlgorithm].Algorithm
+
+	var decOpts crypto.DecrypterOpts
+	pkcs15CertwithOAEP := false
+
+	if ktri.KeyEncryptionAlgorithm.Algorithm.Equal(oid.EncryptionAlgorithmRSAESOAEP) {
+
+		if certPubAlg.Equal(oid.EncryptionAlgorithmRSA) {
+			pkcs15CertwithOAEP = true
+		}
+
+		decOpts, err = parseRSAESOAEPparams(ktri.KeyEncryptionAlgorithm.Parameters.FullBytes)
+		if err != nil {
+			return
+		}
+	}
+
 	//version is the syntax version number.  If the SignerIdentifier is
 	//the CHOICE issuerAndSerialNumber, then the version MUST be 1.  If
 	//the SignerIdentifier is subjectKeyIdentifier, then the version
@@ -71,28 +87,25 @@ func (ktri *KeyTransRecipientInfo) decryptKey(keyPair tls.Certificate) (key []by
 	switch ktri.Version {
 	case 0:
 		if ias.Equal(ktri.Rid.IAS) {
-			alg := oid.PublicKeyAlgorithmToEncrytionAlgorithm[keyPair.Leaf.PublicKeyAlgorithm].Algorithm
+			if ktri.KeyEncryptionAlgorithm.Algorithm.Equal(certPubAlg) || pkcs15CertwithOAEP {
-			if ktri.KeyEncryptionAlgorithm.Algorithm.Equal(alg) {
 
 				decrypter := keyPair.PrivateKey.(crypto.Decrypter)
-				return decrypter.Decrypt(rand.Reader, ktri.EncryptedKey, nil)
+				return decrypter.Decrypt(rand.Reader, ktri.EncryptedKey, decOpts)
 
 			}
 			log.Println("Key encrytion algorithm not matching")
 		}
 	case 2:
 		if bytes.Equal(ski, ktri.Rid.SKI) {
-			alg := oid.PublicKeyAlgorithmToEncrytionAlgorithm[keyPair.Leaf.PublicKeyAlgorithm].Algorithm
+			if ktri.KeyEncryptionAlgorithm.Algorithm.Equal(certPubAlg) || pkcs15CertwithOAEP {
-			if ktri.KeyEncryptionAlgorithm.Algorithm.Equal(alg) {
+
-				if alg.Equal(oid.EncryptionAlgorithmRSA) {
+				decrypter := keyPair.PrivateKey.(crypto.Decrypter)
-					return rsa.DecryptPKCS1v15(rand.Reader, keyPair.PrivateKey.(*rsa.PrivateKey), ktri.EncryptedKey)
+				return decrypter.Decrypt(rand.Reader, ktri.EncryptedKey, decOpts)
-				}
+
-				log.Println("Unsupported key encrytion algorithm")
 			}
 			log.Println("Key encrytion algorithm not matching")
 		}
 	default:
-		fmt.Println(ktri.Version)
 		return nil, ErrUnsupported
 	}
 
@@ -109,35 +122,15 @@ type RecipientIdentifier struct {
 
 // NewRecipientInfo creates RecipientInfo for giben recipient and key.
 func NewRecipientInfo(recipient *x509.Certificate, key []byte) (info RecipientInfo, err error) {
-	version := 0 //issuerAndSerialNumber
-
-	rid := RecipientIdentifier{}
-
-	switch version {
-	case 0:
-		ias, err := NewIssuerAndSerialNumber(recipient)
-		if err != nil {
-			log.Fatal(err)
-		}
-		rid.IAS = ias
-	case 2:
-		rid.SKI = recipient.SubjectKeyId
-	}
 
 	switch recipient.PublicKeyAlgorithm {
 	case x509.RSA:
-		var encrypted []byte
+		var ktri KeyTransRecipientInfo
-		encrypted, err = encryptKeyRSA(key, recipient)
+		ktri, err = encryptKeyRSA(key, recipient)
 		if err != nil {
 			return
 		}
-		info = RecipientInfo{
+		info = RecipientInfo{KTRI: ktri}
-			KTRI: KeyTransRecipientInfo{
-				Version:                version,
-				Rid:                    rid,
-				KeyEncryptionAlgorithm: pkix.AlgorithmIdentifier{Algorithm: oid.EncryptionAlgorithmRSA},
-				EncryptedKey:           encrypted,
-			}}
 	case x509.ECDSA:
 		var kari KeyAgreeRecipientInfo
 		kari, err = encryptKeyECDH(key, recipient)
@@ -152,11 +145,47 @@ func NewRecipientInfo(recipient *x509.Certificate, key []byte) (info RecipientIn
 	return
 }
 
-func encryptKeyRSA(key []byte, recipient *x509.Certificate) ([]byte, error) {
+func encryptKeyRSA(key []byte, recipient *x509.Certificate) (ktri KeyTransRecipientInfo, err error) {
-	if pub := recipient.PublicKey.(*rsa.PublicKey); pub != nil {
+	ktri.Version = 0 //issuerAndSerialNumber
-		return rsa.EncryptPKCS1v15(rand.Reader, pub, key)
+
+	switch ktri.Version {
+	case 0:
+		ias, err := NewIssuerAndSerialNumber(recipient)
+		if err != nil {
+			log.Fatal(err)
 		}
-	return nil, ErrUnsupportedAlgorithm
+		ktri.Rid.IAS = ias
+	case 2:
+		ktri.Rid.SKI = recipient.SubjectKeyId
+	}
+
+	if pub := recipient.PublicKey.(*rsa.PublicKey); pub != nil {
+
+		if isRSAPSS(recipient) {
+			hash := crypto.SHA256
+			var oaepparam RSAESOAEPparams
+			oaepparam, err = newRSAESOAEPparams(hash)
+			if err != nil {
+				return
+			}
+			var oaepparamRV asn1.RawValue
+			oaepparamRV, err = RawValue(oaepparam)
+			if err != nil {
+				return
+			}
+			ktri.KeyEncryptionAlgorithm = pkix.AlgorithmIdentifier{Algorithm: oid.EncryptionAlgorithmRSAESOAEP, Parameters: oaepparamRV}
+			h := hash.New()
+			ktri.EncryptedKey, err = rsa.EncryptOAEP(h, rand.Reader, pub, key, nil)
+			return
+		}
+
+		ktri.KeyEncryptionAlgorithm = pkix.AlgorithmIdentifier{Algorithm: oid.EncryptionAlgorithmRSA}
+		ktri.EncryptedKey, err = rsa.EncryptPKCS1v15(rand.Reader, pub, key)
+		return
+	}
+
+	err = ErrUnsupportedAlgorithm
+	return
 }
 
 // ErrUnsupportedAlgorithm is returned if the algorithm is unsupported.

cms/protocol/signeddata.go

@@ -6,6 +6,7 @@ import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
+	"crypto/rsa"
 	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
@@ -106,7 +107,7 @@ func NewSignedData(eci EncapsulatedContentInfo) (*SignedData, error) {
 }
 
 // AddSignerInfo adds a SignerInfo to the SignedData.
-func (sd *SignedData) AddSignerInfo(keypPair tls.Certificate) (err error) {
+func (sd *SignedData) AddSignerInfo(keypPair tls.Certificate, attrs []Attribute) (err error) {
 
 	for _, cert := range keypPair.Certificate {
 		if err = sd.AddCertificate(cert); err != nil {
@@ -125,8 +126,13 @@ func (sd *SignedData) AddSignerInfo(keypPair tls.Certificate) (err error) {
 
 	sid := SignerIdentifier{ias, nil}
 
+	var signerOpts crypto.SignerOpts
 	digestAlgorithm := digestAlgorithmForPublicKey(cert.PublicKey)
 	signatureAlgorithm, ok := oid.PublicKeyAlgorithmToSignatureAlgorithm[keypPair.Leaf.PublicKeyAlgorithm]
+	if isRSAPSS(cert) {
+		h := oid.DigestAlgorithmToHash[digestAlgorithm.Algorithm.String()]
+		signatureAlgorithm, signerOpts, err = newPSS(h, cert.PublicKey.(*rsa.PublicKey))
+	}
 	if !ok {
 		return errors.New("unsupported certificate public key algorithm")
 	}
@@ -155,6 +161,11 @@ func (sd *SignedData) AddSignerInfo(keypPair tls.Certificate) (err error) {
 	if err != nil {
 		return err
 	}
+
+	if !isRSAPSS(cert) {
+		signerOpts = hash
+	}
+
 	md := hash.New()
 	if _, err = md.Write(content); err != nil {
 		return err
@@ -174,6 +185,7 @@ func (sd *SignedData) AddSignerInfo(keypPair tls.Certificate) (err error) {
 		return err
 	}
 	si.SignedAttrs = append(si.SignedAttrs, mdAttr, ctAttr, sTAttr)
+	si.SignedAttrs = append(si.SignedAttrs, attrs...)
 
 	sm, err := asn.MarshalWithParams(si.SignedAttrs, `set`)
 	if err != nil {
@@ -184,7 +196,7 @@ func (sd *SignedData) AddSignerInfo(keypPair tls.Certificate) (err error) {
 	if _, errr := smd.Write(sm); errr != nil {
 		return errr
 	}
-	if si.Signature, err = signer.Sign(rand.Reader, smd.Sum(nil), hash); err != nil {
+	if si.Signature, err = signer.Sign(rand.Reader, smd.Sum(nil), signerOpts); err != nil {
 		return err
 	}
 
@@ -384,7 +396,11 @@ func (sd *SignedData) Verify(Opts x509.VerifyOptions, detached []byte) (chains [
 		if err != nil {
 			return
 		}
+		switch signer.SignatureAlgorithm.Algorithm.String() {
+		case oid.SignatureAlgorithmRSASSAPSS.String():
+		default:
 			err = cert.CheckSignature(sigAlg, signedMessage, signer.Signature)
+		}
 		if err != nil {
 			return
 		}

oid/oid.go

@@ -29,6 +29,7 @@ var (
 // Signature Algorithm  OIDs
 var (
 	SignatureAlgorithmRSA             = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
+	SignatureAlgorithmRSASSAPSS       = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 10}
 	SignatureAlgorithmECDSA           = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
 	SignatureAlgorithmECDSAwithSHA1   = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}
 	SignatureAlgorithmECDSAwithSHA224 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 1}
@@ -40,6 +41,7 @@ var (
 // Public Key Encryption OIDs
 var (
 	EncryptionAlgorithmRSA       = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
+	EncryptionAlgorithmRSAESOAEP = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 7}
 )
 
 // Digest Algorithm OIDs
@@ -133,6 +135,11 @@ var SignatureAlgorithms = map[string]map[string]x509.SignatureAlgorithm{
 		DigestAlgorithmSHA384.String(): x509.SHA384WithRSA,
 		DigestAlgorithmSHA512.String(): x509.SHA512WithRSA,
 	},
+	SignatureAlgorithmRSASSAPSS.String(): map[string]x509.SignatureAlgorithm{
+		DigestAlgorithmSHA256.String(): x509.SHA256WithRSAPSS,
+		DigestAlgorithmSHA384.String(): x509.SHA384WithRSAPSS,
+		DigestAlgorithmSHA512.String(): x509.SHA512WithRSAPSS,
+	},
 	SignatureAlgorithmECDSA.String(): map[string]x509.SignatureAlgorithm{
 		DigestAlgorithmSHA1.String():   x509.ECDSAWithSHA1,
 		DigestAlgorithmSHA256.String(): x509.ECDSAWithSHA256,

openssl/openssl.go

@@ -25,8 +25,15 @@ func Encrypt(in []byte, cert *x509.Certificate, opts ...string) (der []byte, err
 	pem.Encode(tmpKey, &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw})
 
 	param := []string{SMIME, "-encrypt", "-aes128"}
+	if SMIME == "smime" {
+		// For smime arguments can not be passed after the keyfile
 		param = append(param, opts...)
 		param = append(param, tmpKey.Name())
+	} else {
+		// Keyots have to be passed after the key
+		param = append(param, "-recip", tmpKey.Name())
+		param = append(param, opts...)
+	}
 	der, err = openssl(in, param...)
 
 	return
@@ -76,9 +83,8 @@ func SignDetached(in []byte, cert *x509.Certificate, key crypto.PrivateKey, inte
 		pem.Encode(tmpInterm, &pem.Block{Type: "CERTIFICATE", Bytes: i.Raw})
 	}
 
-	param := []string{SMIME, "-sign", "-nodetach"}
+	param := []string{SMIME, "-sign", "-nodetach", "-signer", tmpCert.Name(), "-inkey", tmpKey.Name(), "-certfile", tmpInterm.Name()}
 	param = append(param, opts...)
-	param = append(param, []string{"-signer", tmpCert.Name(), "-inkey", tmpKey.Name(), "-certfile", tmpInterm.Name()}...)
 	plain, err = openssl(in, param...)
 
 	return

pki/pki.go

@@ -22,6 +22,7 @@ type configuration struct {
 	subject               *pkix.Name
 	issuer                *Identity
 	nextSN                *int64
+	signatureAlgrotim     x509.SignatureAlgorithm
 	priv                  *crypto.Signer
 	isCA                  bool
 	notBefore             *time.Time
@@ -33,6 +34,7 @@ type configuration struct {
 func (c *configuration) generate() *Identity {
 	templ := &x509.Certificate{
 		Subject:               c.getSubject(),
+		SignatureAlgorithm:    c.signatureAlgrotim,
 		IsCA:                  c.isCA,
 		BasicConstraintsValid: true,
 		NotAfter:              c.getNotAfter(),
@@ -195,6 +197,13 @@ func PrivateKey(value crypto.Signer) Option {
 	}
 }
 
+// SignatureAlgorithm is an Option for setting the signature algorithm.
+func SignatureAlgorithm(value x509.SignatureAlgorithm) Option {
+	return func(c *configuration) {
+		c.signatureAlgrotim = value
+	}
+}
+
 // Issuer is an Option for setting the identity's issuer.
 func Issuer(value *Identity) Option {
 	return func(c *configuration) {

smime/smime.go

@@ -6,11 +6,15 @@ package smime
 import (
 	"crypto/tls"
 	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
 	"encoding/base64"
 	"errors"
 	"log"
 	"strings"
 
+	"github.com/InfiniteLoopSpace/go_S-MIME/oid"
+
 	"github.com/InfiniteLoopSpace/go_S-MIME/b64"
 
 	cms "github.com/InfiniteLoopSpace/go_S-MIME/cms"
@@ -23,6 +27,26 @@ type SMIME struct {
 	CMS *cms.CMS
 }
 
+var oidsmimeCapabilities = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 15}
+
+//SMIMECapability ::= SEQUENCE {
+//capabilityID OBJECT IDENTIFIER,
+//parameters ANY DEFINED BY capabilityID OPTIONAL }
+
+//SMIMECapabilities ::= SEQUENCE OF SMIMECapability
+
+func (smime *SMIME) addSMIMECapabilitesAttr() (err error) {
+
+	var smimeCapabilities []pkix.AlgorithmIdentifier
+
+	smimeCapabilities = append(smimeCapabilities, pkix.AlgorithmIdentifier{Algorithm: oid.EncryptionAlgorithmAES128CBC})
+	smimeCapabilities = append(smimeCapabilities, pkix.AlgorithmIdentifier{Algorithm: oid.AEADChaCha20Poly1305})
+
+	err = smime.CMS.AddAttribute(oidsmimeCapabilities, smimeCapabilities)
+
+	return
+}
+
 // New create a new instance of SMIME with given keyPairs.
 func New(keyPair ...tls.Certificate) (smime *SMIME, err error) {
 	CMS, err := cms.New(keyPair...)
@@ -31,6 +55,10 @@ func New(keyPair ...tls.Certificate) (smime *SMIME, err error) {
 	}
 
 	smime = &SMIME{CMS}
+	err = smime.addSMIMECapabilitesAttr()
+	if err != nil {
+		return
+	}
 
 	return
 }