some advise with sm3util and sm2util about java-gm

[SamYuan1990]

@Gsealy , em... what's your point with sm3util?

use SM3Digest constructor lightweight api, don't need involve BC provider (Security.addProvider())

if use MessageDigest.getInstance("SM3", "BC"), need add this code

java-gm/src/main/java/SM3Util.java

Line 29 in 5b5f58e

SM3Digest digest = new SM3Digest();

you mean we don't need Security.addProvider() right?

[davidkhala]

Thanks for raise up this interesting issue.
Is it related to this? https://cloud.tencent.com/developer/article/1605908

[SamYuan1990]

em.... for sm2, from my point of view, we'd better use default, so the code will upgrade with BC.

https://github.com/bcgit/bc-java/blob/bda04fc807b206bd3162e78fb1027e8d077301ef/core/src/main/java/org/bouncycastle/crypto/engines/SM2Engine.java#L55

and it is a good founding, we can adding supports for the mode for sm2.

[Gsealy]

Thanks for raise up this interesting issue.
Is it related to this? https://cloud.tencent.com/developer/article/1605908

ahh, cant see link in comment.. refer can see it

[Gsealy]

em.... for sm2, from my point of view, we'd better use default, so the code will upgrade with BC.

but default mode was modified in official standard.sm2 Public key encryption algorithm

[SamYuan1990]

em.... for sm2, from my point of view, we'd better use default, so the code will upgrade with BC.

but default mode was modified in official standard.sm2 Public key encryption algorithm

some correction,

1. from point of view from interface design, we should add this support.
2. from point of view as dependency management, the default mode will keep same with BC.

which means, I would like to change the code as BC did.
https://github.com/bcgit/bc-java/blob/r1rv68/core/src/main/java/org/bouncycastle/crypto/engines/SM2Engine.java#L43-L66

an interface and a method variable maybe.

the mode was modified, and personally I hope you are able to ask BC to make the change.
Plan A:java-gm depends on BC to create SM2 xxxx in xxx mode.
but not
Plan B:java-gm has it own logic and base on BC to create SM2 xxxx in xxx mode.

For Plan A, when BC upgrade, java-gm can just use latest BC code without any code change.
For Plan B, java-gm should and will monitoring any changes in BC for sm2 and change the code ....

[Gsealy]

yes, default mode can keep same with BC. And add another method for other mode.

[SamYuan1990]

@Gsealy , em... what's your point with sm3util?

[davidkhala]

My opinion about mode support in java-gm is to adopt C1C3C2 only, although I see some SM2Engine constructor use C1C2C3 as default.

[Gsealy]

@Gsealy , em... what's your point with sm3util?

use SM3Digest constructor lightweight api, don't need involve BC provider (Security.addProvider())

if use MessageDigest.getInstance("SM3", "BC"), need add this code

[SamYuan1990]

My opinion about mode support in java-gm is to adopt C1C3C2 only, although I see some SM2Engine constructor use C1C2C3 as default.

see my comments above.