diff --git a/cmd/taler-auditor-offline-signing/main.go b/cmd/taler-auditor-offline-signing/main.go
index 8b21be8..fdb632a 100644
--- a/cmd/taler-auditor-offline-signing/main.go
+++ b/cmd/taler-auditor-offline-signing/main.go
@@ -49,6 +49,7 @@ type Input struct {
 		ReserveClosingDelay RelativeTime   `json:"reserve_closing_delay"`
 		Signkeys            []SignKey      `json:"signkeys"`
 		Denoms              []DenomKey     `json:"denoms"`
+		Auditors            []Auditor      `json:"auditors"`
 		// Recoup []??? `json:"recoup"`
 	} `json:"arguments"`
 }
@@ -75,6 +76,31 @@ type DenomKey struct {
 	MasterSig           EdDSASignature `json:"master_sig"`
 }
 
+type Auditor struct {
+	AuditorName      string         `json:"auditor_name"`
+	AuditorPub       EdDSAPublicKey `json:"auditor_pub"`
+	AuditorUrl       string         `json:"auditor_url"`
+	DenominationKeys []struct {
+		DenomPubH  SHA512Hash     `json:"denom_pub_h"`
+		AuditorSig EdDSASignature `json:"auditor_sig"`
+	} `json:"denomination_keys"`
+}
+
+func (in *Input) checkAuditor(url string, local EdDSAPublicKey) (e error) {
+
+	for _, au := range in.Arguments.Auditors {
+		if au.AuditorUrl == url && au.AuditorPub.Equal(ed25519.PublicKey(local)) {
+			return nil
+		} else if au.AuditorUrl == url {
+			return fmt.Errorf("Public key mismatch for auditor %q! Local: %s, JSON: %s\n", url, local, au.AuditorPub)
+		} else if au.AuditorPub.Equal(ed25519.PublicKey(local)) {
+			return fmt.Errorf("URL mismatch auditor with pub-key %s! Local: %v, JSON: %v\n", au.AuditorPub, url, au.AuditorUrl)
+		}
+	}
+
+	return fmt.Errorf("No such auditor found!  URL: %q, PubKey: %v\n", url, local)
+}
+
 type AbsoluteTime struct {
 	// TODO: en-/decode "never"
 	TMs uint64 `json:"t_ms"`
@@ -87,6 +113,10 @@ type RelativeTime struct {
 
 type EdDSAPublicKey ed25519.PublicKey
 
+func (ep *EdDSAPublicKey) Equal(p ed25519.PublicKey) bool {
+	return ((*ed25519.PublicKey)(ep)).Equal(p)
+}
+
 func (ep *EdDSAPublicKey) UnmarshalJSON(in []byte) (e error) {
 	var buf []byte
 	// decode crockford.base32
@@ -112,6 +142,14 @@ func (ep *EdDSAPublicKey) MarshalJSON() ([]byte, error) {
 	return buf, nil
 }
 
+func (ep EdDSAPublicKey) String() string {
+	enc, err := crockfordEncode([]byte(ep))
+	if err != nil {
+		return fmt.Sprintf("[error crockfordEncode:%v] pub:%v", err, []byte(ep))
+	}
+	return string(enc)
+}
+
 const CURRENCY_LEN = 12
 
 type Amount struct {
@@ -442,6 +480,17 @@ type SignOperation struct {
 
 type SHA512Hash [sha512.Size]byte
 
+func (h *SHA512Hash) UnmarshalJSON(in []byte) (e error) {
+	var buf []byte
+	// decode crockford.base32
+	if buf, e = crockfordDecode(bytes.Trim(in, `"`)); e != nil {
+		return fmt.Errorf("couldn't decode SHA512 as crockford.base32: %v (%v)", e, string(in))
+	}
+
+	copy([]byte(h[:]), buf[:sha512.Size])
+	return nil
+}
+
 func (h *SHA512Hash) MarshalJSON() ([]byte, error) {
 	enc, err := crockfordEncode((*h)[:])
 	if err != nil {
@@ -483,7 +532,7 @@ func Verify(denom *DenomKey, master *EdDSAPublicKey, sig []byte) bool {
 		4 + // purpose
 		ed25519.PublicKeySize + // master
 		4*8 + // start and expire*
-		5*(8+4+len(denom.Value.Currency)) + // value and fee*
+		5*(8+4+CURRENCY_LEN) + // value and fee*
 		sha512.Size // denomHash
 	buf := make([]byte, size)
 
@@ -503,13 +552,14 @@ func Verify(denom *DenomKey, master *EdDSAPublicKey, sig []byte) bool {
 		be.PutUint64(buf[n:], v*1000) // milli -> micro
 		n += 8
 	}
-	for _, v := range [][]byte{
-		denom.Value.Binary(),
-		denom.FeeWithdraw.Binary(),
-		denom.FeeDeposit.Binary(),
-		denom.FeeRefresh.Binary(),
-		denom.FeeRefund.Binary(),
+	for _, f := range [](func() []byte){
+		denom.Value.Binary,
+		denom.FeeWithdraw.Binary,
+		denom.FeeDeposit.Binary,
+		denom.FeeRefresh.Binary,
+		denom.FeeRefund.Binary,
 	} {
+		v := f()
 		copy(buf[n:], v)
 		n += len(v)
 	}
@@ -551,7 +601,7 @@ func SignDenom(denom *DenomKey, ahash SHA512Hash, master *EdDSAPublicKey, pk *ed
 		sha512.Size + // auditor_url_hash
 		ed25519.PublicKeySize + // master
 		4*8 + // start and expire*
-		5*(8+4+len(denom.Value.Currency)) + // value and fee*
+		5*(8+4+CURRENCY_LEN) + // value and fee*
 		sha512.Size // denomHash
 	buf := make([]byte, size)
 
@@ -573,17 +623,21 @@ func SignDenom(denom *DenomKey, ahash SHA512Hash, master *EdDSAPublicKey, pk *ed
 		be.PutUint64(buf[n:], v*1000) // milli -> micro
 		n += 8
 	}
-	for _, v := range [][]byte{
-		denom.Value.Binary(),
-		denom.FeeWithdraw.Binary(),
-		denom.FeeDeposit.Binary(),
-		denom.FeeRefresh.Binary(),
-		denom.FeeRefund.Binary(),
+	for _, f := range [](func() []byte){
+		denom.Value.Binary,
+		denom.FeeWithdraw.Binary,
+		denom.FeeDeposit.Binary,
+		denom.FeeRefresh.Binary,
+		denom.FeeRefund.Binary,
 	} {
+		v := f()
 		copy(buf[n:], v)
 		n += len(v)
 	}
 	bin := denom.DenomPub.Binary()
+	// Future:
+	// bin = append(bin, 0, 0, 0, 0) // age mask
+	// bin = append(bin, 0, 0, 0, 1) // cipher == RSA
 	hash := sha512.Sum512(bin)
 	copy(buf[n:], hash[:])
 
@@ -649,7 +703,7 @@ func main() {
 		var dec *json.Decoder
 
 		input := new(Input)
-		if *injson == "-" {
+		if *injson == "-" || *injson == "" {
 			dec = json.NewDecoder(os.Stdin)
 		} else {
 			f, e := os.Open(*injson)
@@ -665,6 +719,11 @@ func main() {
 			log.Fatal(e)
 		}
 
+		e = input.checkAuditor(*url, EdDSAPublicKey(pub))
+		if e != nil {
+			log.Fatal(e)
+		}
+
 		output, err := Sign(input, *url, pk)
 		if err != nil {
 			log.Fatalf("error signing: %v", err)