IBM Crypto Education Community

Hello.   I find myself looking to create a KCVfor a DES key.   I have code using ENC to create one for me.  It seems to require CBC and will not allow EBC.   And I'm wondering if using EBC would give me a different KCV result.   To that end, I've been looking for a data encryption call that would allow me to create KCV using EBC.  I can't find one in the application programmers guide.

Would anyone else have ideas that would point me into a direction to accomplish this goal?

Does anyone already know the CBC or EBC does not matter when generating a KCV?

Your feedback to get me started on a solution for this would be appreciated.

Sincerely,

Mark Vollmer

It usually doesn't matter for most kinds of KCVs. You might want to use CSNBKYT to generate key test values instead. CSNBENC will only work for data-encryption keys that are allowed to do encryption and will fail for keys like PINGEN, etc.

Hello.   I find myself looking to create a KCVfor a DES key.   I have code using ENC to create one for me.  It seems to require CBC and will not allow EBC.   And I'm wondering if using EBC would give me a different KCV result.   To that end, I've been looking for a data encryption call that would allow me to create KCV using EBC.  I can't find one in the application programmers guide.

Would anyone else have ideas that would point me into a direction to accomplish this goal?

Does anyone already know the CBC or EBC does not matter when generating a KCV?

Your feedback to get me started on a solution for this would be appreciated.

Sincerely,

Mark Vollmer

Eric,

Thanks for helping out.   Is it  your belief that I can use ENC-ZERO in this BKYT call and an encrypted import/export key to create a KCV that was performed using ECB?

Sincerely,

Mark Vollmer

It usually doesn't matter for most kinds of KCVs. You might want to use CSNBKYT to generate key test values instead. CSNBENC will only work for data-encryption keys that are allowed to do encryption and will fail for keys like PINGEN, etc.

Hello.   I find myself looking to create a KCVfor a DES key.   I have code using ENC to create one for me.  It seems to require CBC and will not allow EBC.   And I'm wondering if using EBC would give me a different KCV result.   To that end, I've been looking for a data encryption call that would allow me to create KCV using EBC.  I can't find one in the application programmers guide.

Would anyone else have ideas that would point me into a direction to accomplish this goal?

Does anyone already know the CBC or EBC does not matter when generating a KCV?

Your feedback to get me started on a solution for this would be appreciated.

Sincerely,

Mark Vollmer

Yes, that will work.

I just tried it with a 16-byte DES key using both ECB and CBC (with an all zero IV) modes and got the same first 4 bytes as returned from CSNBKYT using rules 'KEY-ENCDGENERATEENC-ZERO'

Eric,

Thanks for helping out.   Is it  your belief that I can use ENC-ZERO in this BKYT call and an encrypted import/export key to create a KCV that was performed using ECB?

Sincerely,

Mark Vollmer

It usually doesn't matter for most kinds of KCVs. You might want to use CSNBKYT to generate key test values instead. CSNBENC will only work for data-encryption keys that are allowed to do encryption and will fail for keys like PINGEN, etc.

Hello.   I find myself looking to create a KCVfor a DES key.   I have code using ENC to create one for me.  It seems to require CBC and will not allow EBC.   And I'm wondering if using EBC would give me a different KCV result.   To that end, I've been looking for a data encryption call that would allow me to create KCV using EBC.  I can't find one in the application programmers guide.

Would anyone else have ideas that would point me into a direction to accomplish this goal?

Does anyone already know the CBC or EBC does not matter when generating a KCV?

Your feedback to get me started on a solution for this would be appreciated.

Sincerely,

Mark Vollmer

Eric,

I can't thank you enough.   I too was able to perform the comparison and got the same KCV results. 

Thanks very much.

Sincerely,

Mark Vollmer

Yes, that will work.

I just tried it with a 16-byte DES key using both ECB and CBC (with an all zero IV) modes and got the same first 4 bytes as returned from CSNBKYT using rules 'KEY-ENCDGENERATEENC-ZERO'

Eric,

Thanks for helping out.   Is it  your belief that I can use ENC-ZERO in this BKYT call and an encrypted import/export key to create a KCV that was performed using ECB?

Sincerely,

Mark Vollmer

It usually doesn't matter for most kinds of KCVs. You might want to use CSNBKYT to generate key test values instead. CSNBENC will only work for data-encryption keys that are allowed to do encryption and will fail for keys like PINGEN, etc.

Hello.   I find myself looking to create a KCVfor a DES key.   I have code using ENC to create one for me.  It seems to require CBC and will not allow EBC.   And I'm wondering if using EBC would give me a different KCV result.   To that end, I've been looking for a data encryption call that would allow me to create KCV using EBC.  I can't find one in the application programmers guide.

Would anyone else have ideas that would point me into a direction to accomplish this goal?

Does anyone already know the CBC or EBC does not matter when generating a KCV?

Your feedback to get me started on a solution for this would be appreciated.

Sincerely,

Mark Vollmer