uplinks:: EC Key Pair
tags:: #lang/en

Compressed EC Public Key

• Due to the nature of an Elliptic Curve, an EC public key, which is an EC point, can be represented with the $x$-coordinate and one extra bit for $y$ or $-y$
• Compresed public keys in Bitcoin are 33 bytes, consisting of a prefix either $\text{0x02}$ or $\text{0x03}$, followed by a 32-byte $x$-coordinate integer
  • $\text{0x02}$ if $y$ is even
  • $\text{0x03}$ if $y$ is odd

See Also

1. Uncompressed EC Public Key