River Intelligence

Sign up for our curated weekly newsletter delivering exclusive market insights to your inbox.

Invest in Bitcoin.

Human Support

Track Performance

Recurring Buys

DER Format


The Distinguished Encoding Rules (DER) format is a defined standard which Bitcoin uses to encode ECDSA signatures. A signature consists of a random number called an r value, and the signature itself, called the s value. A typical Bitcoin signature is 71 bytes long, as a one byte sighash flag is appended to the DER signature, and these bytes are represented in hexadecimal format.

DER format begins with a prefix byte of 0x30, followed by the length of the signature. Next comes an 0x02 byte followed by the length of the r value, followed by the r value itself. Finally, an 0x02, the length of the s value, and the s value are added. For both r and s values, if the first byte is higher than 0x80, an additional 0x00 byte is prepended to the value. So, while r and s values are both 32 bytes long, they occasionally take up 33 bytes in DER format.