counter needs to based on maxlen(p) as tag done on J0

1 files changed, 2 insertions, 2 deletions

diff --git a/crypto/src/crypto/modes/GCMBlockCipher.cs b/crypto/src/crypto/modes/GCMBlockCipher.cs

index fbbc242a1..9d940fe75 100644
--- a/crypto/src/crypto/modes/GCMBlockCipher.cs
+++ b/crypto/src/crypto/modes/GCMBlockCipher.cs
@@ -174,7 +174,7 @@ namespace Org.BouncyCastle.Crypto.Modes
             this.atLength = 0;
             this.atLengthPre = 0;
             this.counter = Arrays.Clone(J0);
-            this.blocksRemaining = uint.MaxValue; // page 8, len(P) <= 2^39 - 256, 1 block used by tag
+            this.blocksRemaining = uint.MaxValue - 1; // page 8, len(P) <= 2^39 - 256, 1 block used by tag
             this.bufOff = 0;
             this.totalLength = 0;
 
@@ -449,7 +449,7 @@ namespace Org.BouncyCastle.Crypto.Modes
             atLength = 0;
             atLengthPre = 0;
             counter = Arrays.Clone(J0);
-            blocksRemaining = uint.MaxValue;
+            blocksRemaining = uint.MaxValue - 1;
             bufOff = 0;
             totalLength = 0;