Output of .Net 1.1 C# encryption/Decryption not in sync with java

Question

Given Values: Parameter which should be encrypted KEY to encrypt

Algorithm @>Net 1.1 C#:

first converts original Parameter to bytesarry (using Unicode little-endian encoding) ->Byte_Expression
Fillup Byte_Expression with padding chars (0): Fillfactor is 8 (fill up to 8Bytes) -> Byte_Expression8
Now converts the KEY from String to Base64encoded ByteArray -> ByteKEY
Crypted Byte_Expression8 with DES3:
Ciphermode: ECB (Electronic Code Book)
Padding: with Zeros
DEFAULTINITIALVECTOR: = {0×00, 0×00, 0×00, 0×00, 0×00, 0×00, 0×00, 0×00}
Key = ByteKEY (ref 3)
DES3ecryptedByteArray
Convert the DES3ecryptedByteArray with Base64Encryption to String -> Encrypted Parameter
Finish

Have used above Alogorithm @Java7. In ECB Encryption mode it is throwing an error, however it is working fine with CBC mode.

Result : OUTPUT of .Net & Java not is snyc

Issue: java.security.InvalidAlgorithmParameterException: ECB mode cannot use IV

Please supply source code and a full stack trace next time. Step 3 doesn't make any sense to me. — Maarten Bodewes
– Maarten Bodewes, Commented Feb 12, 2015 at 7:45
Are you sure you are not decoding the key in step 3? Not that it matters for the answer, but encoding a key in base64 would not be secure. — Maarten Bodewes
– Maarten Bodewes, Commented Feb 12, 2015 at 7:52

Maarten Bodewes · Accepted Answer · 2015-02-12 07:45:13Z

2

ECB does not support an IV, so in Java the Cipher.init method with a third parameter should not be used. Some libraries allow inserting an IV value for ECB (notably PHP's mcrypt wrapper and apparently .NET) but in those cases the IV is simply ignored. Fortunately I haven't seen an implementation yet that uses the IV only for the first block during ECB encryption.

If CBC mode is used - ECB is not secure - then a zero IV means that the first block will be identical to ECB mode (direct AES encryption). This means that multiple encrypts with the same key are not secure either. CBC requires a random IV value.

answered Feb 12, 2015 at 7:45

Maarten Bodewes

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