diff --git a/Include/Library/OcCryptoLib.h b/Include/Library/OcCryptoLib.h
index 35959dca..9923c270 100644
--- a/Include/Library/OcCryptoLib.h
+++ b/Include/Library/OcCryptoLib.h
@@ -108,8 +108,7 @@ BOOLEAN
 RsaVerify (
   RSA_PUBLIC_KEY  *Key,
   UINT8           *Signature,
-  UINT8           *Sha256,
-  UINT32          *Workbuf32
+  UINT8           *Sha256
   );
 
 VOID
diff --git a/Library/OcAppleChunklistLib/OcAppleChunklistLib.c b/Library/OcAppleChunklistLib/OcAppleChunklistLib.c
index 44c96f5d..c1456737 100644
--- a/Library/OcAppleChunklistLib/OcAppleChunklistLib.c
+++ b/Library/OcAppleChunklistLib/OcAppleChunklistLib.c
@@ -98,16 +98,13 @@ OcAppleChunklistVerifySignature (
 {
   BOOLEAN Result;
 
-  UINT32  WorkBuf32[RSANUMWORDS * 3];
-
   ASSERT (Context != NULL);
   ASSERT (Context->Signature != NULL);
 
   Result = RsaVerify (
              PublicKey,
              Context->Signature->Signature,
-             Context->Hash,
-             WorkBuf32
+             Context->Hash
              );
   DEBUG_CODE (
     if (Result) {
diff --git a/Library/OcAppleImageVerificationLib/OcAppleImageVerification.c b/Library/OcAppleImageVerificationLib/OcAppleImageVerification.c
index 55126d3a..d92d1c6c 100644
--- a/Library/OcAppleImageVerificationLib/OcAppleImageVerification.c
+++ b/Library/OcAppleImageVerificationLib/OcAppleImageVerification.c
@@ -615,7 +615,6 @@ VerifyApplePeImageSignature (
   IN OUT APPLE_PE_COFF_LOADER_IMAGE_CONTEXT  *Context OPTIONAL
   )
 {
-  UINT32                   WorkBuf32[RSANUMWORDS * 3];
   UINTN                    Index                       = 0;
   APPLE_SIGNATURE_CONTEXT  *SignatureContext           = NULL;
   RSA_PUBLIC_KEY           *Pk                         = NULL;
@@ -695,7 +694,7 @@ VerifyApplePeImageSignature (
   //
   // Verify signature
   //
-  if (RsaVerify (Pk, SignatureContext->Signature, Context->PeImageHash, WorkBuf32) == 1 ) {
+  if (RsaVerify (Pk, SignatureContext->Signature, Context->PeImageHash) == 1 ) {
     DEBUG ((DEBUG_INFO, "Signature verified!\n"));
     FreePool (SignatureContext);
     FreePool (Context);
diff --git a/Library/OcCryptoLib/Rsa2048Sha256.c b/Library/OcCryptoLib/Rsa2048Sha256.c
index 570704d2..5a32f4db 100644
--- a/Library/OcCryptoLib/Rsa2048Sha256.c
+++ b/Library/OcCryptoLib/Rsa2048Sha256.c
@@ -183,15 +183,12 @@ MontMul (
 
   @param Key        Key to use in signing
   @param InOut      Input and output big-endian byte array
-  @param Workbuf32  Work buffer; caller must verify this is
-                    3 x RSANUMWORDS elements long.
  **/
 STATIC
 VOID
 ModPow (
   RSA_PUBLIC_KEY  *Key,
-  UINT8           *InOut,
-  UINT32          *Workbuf32
+  UINT8           *InOut
   )
 {
   UINT32 *A     = NULL;
@@ -201,6 +198,8 @@ ModPow (
   INT32  Index  = 0;
   UINT32 Tmp    = 0;
 
+  UINT32 Workbuf32[RSANUMWORDS * 3];
+
   A = Workbuf32;
   Ar = A + RSANUMWORDS;
   Aar = Ar + RSANUMWORDS;
@@ -290,16 +289,14 @@ CheckPadding (
   @param Key         RSA public key
   @param Signature   RSA signature
   @param Sha256      SHA-256 digest of the content to verify
-  @param Workbuf32   Work buffer; caller must verify this is
-                     3 x RSANUMWORDS elements long.
+
   @return FALSE on failure, TRUE on success.
  **/
 BOOLEAN
 RsaVerify (
   RSA_PUBLIC_KEY  *Key,
   UINT8           *Signature,
-  UINT8           *Sha256,
-  UINT32          *Workbuf32
+  UINT8           *Sha256
   )
 {
   UINT8 Buf[RSANUMBYTES];
@@ -312,7 +309,7 @@ RsaVerify (
   //
   // In-place exponentiation
   //
-  ModPow (Key, Buf, Workbuf32);
+  ModPow (Key, Buf);
 
   //
   // Check the PKCS#1 padding
diff --git a/Tools/AppleEfiSignTool/AppleEfiBinary.c b/Tools/AppleEfiSignTool/AppleEfiBinary.c
index 8ba41e12..9c71363a 100644
--- a/Tools/AppleEfiSignTool/AppleEfiBinary.c
+++ b/Tools/AppleEfiSignTool/AppleEfiBinary.c
@@ -428,7 +428,6 @@ VerifyApplePeImageSignature (
   uint8_t                            SigBe[256];
   uint8_t                            CalcucatedHash[32];
   uint8_t                            PkHash[32];
-  uint32_t                           WorkBuf32[RSANUMWORDS*3];
   RSA_PUBLIC_KEY                     *Pk                      = NULL;
   APPLE_PE_COFF_LOADER_IMAGE_CONTEXT *Context                 = NULL;
 
@@ -492,7 +491,7 @@ VerifyApplePeImageSignature (
   //
   // Verify signature
   //
-  if (RsaVerify (Pk, SigBe, CalcucatedHash, WorkBuf32) == 1 ) {
+  if (RsaVerify (Pk, SigBe, CalcucatedHash) == 1 ) {
     puts ("Signature verified!\n");
     return 0;
   }