Why he did it? Because we are not provided of the original Sartre text and therefore is impossible to compute the valid SHA256 image (which text? how is formatted? which charset? newlines? every little change in the text would change the hash) and we cannot search for a given hex string into the blockchain. Wright tried to sell to the world and old signature of a transaction as a signature of the hash of a text. The algorithm are the same, if the "transaction" and "file" are the same, or better, if their hashes are the same, one signature for the transaction is a valid signature for the file and viceversa. The Bitcoin protocol describe how a transaction has to be signed: The clever move by Wright is to sign the SHA256 of this file, so the final signature is something like:Īnd one may remark the double use of the hash function SHA256 (while a standard signature would be something like secp256k1(sha256(message)). As the text is big, the signature is the decryption of the hash of this text. Wright claimed that he provided a signature on a large file, a text from Sartre. It's, as someone suggested, like to cut out the last page from a contract, paste it to another contract and claim the new contract is ok. Craig Wright has recovered an old (and real) Satoshi's signature and tried to provide it as a new signature to validate his identity. The scam is not based on a cryptographic attak but on what is signed. The disadvantage with this approach is that the ratio of output characters to input bytes is not fixed.Short version: the signature is correct, it is a real signature and therefore it is possible to verify it with one's favourite software. To review, open the file in an editor that reveals hidden Unicode characters. Base64 encoding schemes are commonly used when there is a need to encode binary data, especially. Base64 encode your data without hassles or decode it into a human-readable format. This too could be done as a pre/post step if you don't want to write your own encoder/decoder from the ground-up. This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. Meet Base64 Decode and Encode, a simple online tool that does exactly what it says: decodes from Base64 encoding as well as encodes into it quickly and easily. For instance, 0 (A) would be encoded as "AA", 62 (+) would be encoded as "AB" and 63 (/) would be encoded as "AC". If you have no alternative suitable "funny" characters to choose from (perhaps all the other characters are invalid leaving only the 62 alphanumeric characters to choose from), you can always use an escape character for a very slight (~3/64?) increase in size. Download or copy the result from the Text field. If you know what encoding the original data was in, select it in the Character Encoding list. Skeet points out, find an existing library with enough flexibility. Enable the strict decoding mode if you want to make sure that your Base64 string contains only valid characters. Download or copy the result from the Hex field. The current assumption that the backup file is always in Downloads is not always right. Incidentally, it would be really handy if Bitcoin Wallet could add a file association to automatically open wallet backup files. I switched to ES File Explorer and the wallet imported just fine. Specify a delimiter to separate hex digits. That's why trim()ing the string before base64 decode worked. Limit the output length if you need to extract a certain number of bytes. Select the desired letter case for the hex value. While base64 encoder/decoders are trivial, replacement subsitution can be done in a simple pre/post processing step of an existing base64 encode/decode functions (inside wrappers) - no need to re-invent the wheel (entirely). Type or paste your Base64 value into the Base64 field. Consider some other variants: base64 Variant table from Wikipedia.
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