Solve IllegalBlockSizeException: last block incomplete in decrypt

Recently implemented encryption and decryption, but found the following exceptions:
Javax. crypto. illegalBlockSizeException: last block incomplete in decryption at org. bouncycastle. jce. provider. JCEBlockCipher. engineDoFinal (JCEBlockCipher. java: 711) at javax. crypto. cipher. doFinal (Cipher. java: 1090)

Google, and summarize the results
Cause:
It may be because a string's byte [] string is directly encrypted into a ciphertext. During transmission, data may be lost due to the default encoding method. (If you have a better explanation, please note)
Solution:
The encrypted ciphertext is encrypted with base64 as a whole. During decoding, base64 is decrypted before DES/AES is decrypted. This ensures that the accepted data is correct and will not be missing.

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