diff --git a/ssh-transport.rkt b/ssh-transport.rkt
index 8f33132..79c23e8 100644
--- a/ssh-transport.rkt
+++ b/ssh-transport.rkt
@@ -688,35 +688,33 @@
   (define enc (if c2s c2s-enc s2c-enc))
   (define mac (if c2s c2s-mac s2c-mac))
   (define zip (if c2s c2s-zip s2c-zip))
+
+  (define cipher-description
+    (cond
+     ((assq enc supported-crypto-algorithms) => cadr)
+     (else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
+				  "Could not find driver for encryption algorithm ~v"
+				  enc))))
+  (define cipher ((supported-cipher-factory cipher-description)
+		  is-outbound?
+		  (derive-key (if c2s #"C" #"D") (supported-cipher-key-length cipher-description))
+		  (derive-key (if c2s #"A" #"B") (supported-cipher-iv-length cipher-description))))
+
+  (define hmac-description
+    (cond
+     ((assq mac supported-hmac-algorithms) => cadr)
+     (else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
+				  "Could not find driver for HMAC algorithm ~v"
+				  mac))))
+  (define hmac ((supported-hmac-factory hmac-description)
+		(derive-key (if c2s #"E" #"F") (supported-hmac-key-length hmac-description))))
+
+  (pretty-print `(,is-server? ,(if c2s 'c2s 's2c) ,enc ,mac))
   (struct-copy stream-state state
-   [cipher (cond
-	    ((assq enc supported-crypto-algorithms) =>
-	     (lambda (entry)
-	       (define c (cadr entry))
-	       (define key (derive-key (if c2s #"C" #"D")
-				       (supported-cipher-key-length c)))
-	       (define iv (derive-key (if c2s #"A" #"B")
-				      (supported-cipher-iv-length c)))
-	       (define factory (supported-cipher-factory c))
-	       ;; (pretty-print `(,is-server? ,(if c2s 'c2s 's2c) ,enc
-	       ;; 				   (key ,(hex key)) (iv ,(hex iv))))
-	       (factory is-outbound? key iv)))
-	    (else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
-					 "Could not find driver for encryption algorithm ~v"
-					 enc)))]
-   [hmac (cond
-	  ((assq mac supported-hmac-algorithms) =>
-	   (lambda (entry)
-	     (define h (cadr entry))
-	     (define factory (supported-hmac-factory h))
-	     (define key (derive-key (if c2s #"E" #"F")
-				     (supported-hmac-key-length h)))
-	     ;; (pretty-print `(,is-server? ,(if c2s 'c2s 's2c) ,mac
-	     ;; 				 (key ,(hex key))))
-	     (factory key)))
-	  (else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
-				       "Could not find driver for HMAC algorithm ~v"
-				       mac)))]))
+	       [cipher cipher]
+	       [cipher-description cipher-description]
+	       [hmac hmac]
+	       [hmac-description hmac-description]))
 
 ;; PacketHandler for handling SSH_MSG_KEXINIT.
 (define (handle-msg-kexinit packet message conn)