code: func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
  	if len(src)%x.blockSize != 0 {
  		panic("ECBDecrypter: input not full blocks")
  	}
  	if len(dst) < len(src) {
  		panic("ECBDecrypter: output smaller than input")
  	}
  	// See https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_Codebook_.28ECB.29
  	for len(src) > 0 {
  		x.b.Decrypt(dst, src[:x.blockSize])
  		src = src[x.blockSize:]
  		dst = dst[x.blockSize:]
  	}
  }
docs: // CryptBlocks implements BlockMode.CryptBlocks interface.