Decode/encode Java

Question

My problem is revert operation encode .

String computedLtpaTokenMd5 = new String(Base64.encodeBase64(MessageDigest.getInstance("MD5").digest(ltpaToken.getBytes())));

how to recover the token ltpaToken by computedLtPaTOkenMD5?

Answer 1

You cannot.

That is the whole point of a cryptographic hash function (which MD5 is, or rather was, you should not use it anymore): It is one-way.

All you can do is check if a given token matches that hashed value (by running the same hash function again and either getting the same output or not).

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(You can reverse the Base64 encoding, but not the MD5 hashing)