Fix envelope decryption bug when encrkeylen=255

1 files changed, 1 insertions, 1 deletions

diff --git a/envelope.cpp b/envelope.cpp
index a8cd793..9bb011e 100644
--- a/envelope.cpp
+++ b/envelope.cpp
@@ -57,7 +57,7 @@ namespace Envelope{
 	string decrypt(const string &data,const RSA::PrivateKey &privkey){
 		cerr<<"=== DECRYPT ==="<<endl;
 		if(data.size()<2)throw invalid_argument("Envelope data length invalid");
-		int encrkeylen=((uint16_t)data[data.size()-2]<<8)+(uint16_t)data.back();
+		int encrkeylen=((uint16_t)(uint8_t)data[data.size()-2]<<8)+(uint8_t)data.back();
 		assert(encrkeylen<(1<<16));
 		cerr<<"encrkeylen="<<encrkeylen<<endl;
 		if((int)data.size()<encrkeylen+2)throw invalid_argument("Envelope key format invalid");