diff --git a/signature.h b/signature.h
index d2a8843..5737881 100644
--- a/signature.h
+++ b/signature.h
@@ -1,5 +1,6 @@
 #define SHA256_DIGEST_SIZE  32
 
+EFI_GUID EfiHashSha1Guid = { 0x826ca512, 0xcf10, 0x4ac9, {0xb1, 0x87, 0xbe, 0x1, 0x49, 0x66, 0x31, 0xbd }};
 EFI_GUID EfiHashSha256Guid = { 0xc1c41626, 0x504c, 0x4092, {0xac, 0xa9, 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28 }};
 EFI_GUID EfiCertX509Guid = { 0xa5c059a1, 0x94e4, 0x4aa7, {0x87, 0xb5, 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72 }};