Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

8287178: IntegerModuloP::multiplicativeInverse returns 0 for 0 #9115

Closed
wants to merge 2 commits into from
Closed

8287178: IntegerModuloP::multiplicativeInverse returns 0 for 0 #9115

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
36741bb
add comment
wangweij Jun 9, 2022
15ef85f
verb
wangweij Jun 9, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
9 changes: 8 additions & 1 deletion src/java.base/share/classes/sun/security/util/math/IntegerModuloP.java
View file
Open in desktop
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -156,6 +156,13 @@ default byte[] asByteArray(int len) {
* @return the multiplicative inverse (1 / this)
*/
default ImmutableIntegerModuloP multiplicativeInverse() {
// This method is used in 2 cases:
// 1. To calculate the inverse of a number in ECDSAOperations,
// this number must be non zero (modulo p).
// 2. To flatten a 3D point to a 2D AffinePoint. This number
// might be zero (infinity). However, since the infinity
// is represented as (0, 0) in 2D, it’s OK returning 0 as
// the inverse of 0, i.e. (1, 1, 0) == (1/0, 1/0) == (0, 0).
return pow(getField().getSize().subtract(BigInteger.valueOf(2)));
}

Expand Down